Presented by 
 Dr. Pearl Oliphant 
 
 COLLEGE OP' OSTEOPATH 1C PHYSICIANS 
 AND SURGEONS LOS ANGELES, CALIFORNIA ~
 
 THE FORMATION 
 
 OF 
 
 VEGETABLE MOULD, 
 
 THROUGH THE 
 
 ACTION OF WOEMS, 
 
 WITH 
 
 OBSERVATIONS ON THEIR HABITS. 
 
 BY CHAELES DAEWIN, LL.D,, F.E.S. 
 
 THIRTEENTH THOUSAND. 
 
 WITH ILLUSTRATIONS. 
 
 LONDON: 
 JOHN MUREAY, ALBEMAELE STEEET.. 
 
 1897.
 
 UNIFORM EDITIONS. 
 
 WORKS BY CHARLES DARWIN, F.R.S. 
 
 LIFE AND LETTERS OF CHARLES DARWIN. With 
 an Autobiographical Chapter. Edited by FRANCIS DARWIN. Portraits. 
 3 vols. 36s. 
 
 NATURALIST'S JOURNAL OF RESEARCHES INTO THE 
 NATURAL HISTORY AND GEOLOGY OF COUNTRIES VISITED during a VOYAGE 
 ROUND THK WORLD. With 1 00 Illustrations by PRITCHETT. 21s. Popular 
 Edition. Woodcuts. 3s. 6d. 
 
 I -, / ^ORIGIN OF SPECIES BY MEANS OF NATURAL. SELEC- 
 
 ' \\ J> \)O TION ; or, THE PRESERVATION OF FAVOURED RACES IN THE STRUGGLE FOR 
 
 LIFE. Large Type Edition, with Portrait. 2 vols. 12s. Popular Edition, 6s. 
 
 VARIOUS CONTRIVANCES BY WHICH ORCHIDS ARE 
 FERTILIZED BY INSECTS. Woodcuts. 7s. 6d. 
 
 O r-, VARIATION OF ANIMALS AND PLANTS UNDER DO- 
 MESTICATION. Illustrations. 15*. 
 
 DESCENT OF MAN, AND SELECTION IN RELATION TO 
 
 SEX. Illustrations. Large Type Edition, 2 vuls. 15s. Popular Edition, 
 It. 6d. 
 
 EXPRESSION OF THE EMOTIONS IN MAN AND 
 
 ANIMALS. Illustrations. 12s. 
 
 INSECTIVOROUS PLANTS. Illustrations. 9s. 
 
 MOVEMENTS AND HABITS OF CLIMBING PLANTS. 
 Woodcuts. 6s. 
 
 EFFECTS OF CROSS AND SELF-FERTILIZATION IN 
 
 THE VEGETABLE KINGDOM. Illustrations. 9s. 
 
 DIFFERENT FORMS OF FLOWERS ON PLANTS OF 
 
 THE SAME SPECIES. Illustrations. 7s. 6d. 
 
 LIFE OF ERASMUS DARWIN. Is. Qd. 
 POWER OF MOVEMENT IN PLANTS. 
 
 THROUGH THE 
 
 FACTS AND ARGUMENTS FOR DARWIN. By FRITZ 
 
 HttUB. 
 
 The above works are Published by JOHN MURRAY. 
 STRUCTURE AND DISTRIBUTION OF CORAL REEFS. 
 
 SMITH, ELDER, & Co. 
 GEOLOGICAL OBSERVATIONS ON VOLCANIC ISLANDS 
 
 AND PARTS OF SOUTH AMERICA. SMITH ELDER, & Co. 
 
 MONOGRAPH OF THE CIRRIPEDIA. Illustrations. 2 vols. 
 
 RAT SOCIETY. 
 
 PALOXTOGRArHICAL SOCIETY. 
 
 WOGRAPH OF THE FOSSIL BALANIDM AND VER- 
 RUCIDjE OF GREAT BRITAIN. PAL.EONTOGBAPHICAL SOCIETY. 
 
 ucnxw: PSINTBD BY WILLIAM CLOWES AJ.-D SONS, LIMITED, 
 
 tTAXIDIU) STREET ASD CHABINO CEO68.
 
 CONTENTS. 
 
 INTRODUCTION. .... Pages 1-7 
 
 CHAPTEE I. 
 
 HABITS OF WORMS. 
 
 Nature of the sites inhabited Can live long under 
 water Nocturnal Wander about at night Often 
 lie close to the mouths of their burrows, and are 
 thus destroyed in large numbers by birds Structure 
 Do not possess eyes, but can distinguish between 
 light and darkness Retreat rapidly when brightly 
 illuminated, not by a reflex action Power of atten- 
 tion Sensitive to heat and cold Completely deaf 
 Sensitive to vibrations and to touch Feeble 
 power of smell Taste Mental qualities Nature 
 of food Omnivorous Digestion Leaves, before 
 being swallowed, moistened with a fluid of the 
 nature of the pancreatic secretion Extra-stomachal 
 digestion Calciferous glands, structure of Cal- 
 careous concretions formed in the anterior pair of 
 glands The calcareous matter primarily an excre- 
 tion, but secondarily serves to neutralise the acids 
 generated during the digestive process . 8-56
 
 iv CONTENTS. 
 
 CHAPTER II. 
 
 HABITS OF WORMS continued. 
 
 Manner in which worms seize objects Their power of 
 suction The instinct of plugging up the mouths of 
 their burrows Stones piled over the burrows 
 The advantages thus gained Intelligence shown by 
 worms in their manner of plugging up their burrows 
 Various kinds of leaves and other objects thus 
 used Triangles of paper Summary of reasons for 
 believing that worms exhibit some intelligence 
 Means by which they excavate their burrows, by 
 pushing away the earth and swallowing it Earth 
 also swallowed for the nutritious matter which it 
 contains Depth to which "worms burrow, and the 
 construction of their burrows Burrows lined with 
 castings, and in the upper part with leaves The 
 lowest part paved with little stones or seeds 
 Manner in which the castings are ejected The 
 collapse of old burrows Distribution of worms 
 Tower-like castings in Bengal Gigantic castings 
 on the Kilgiri Mountains Castings ejected in all 
 countries Pages 57-130 
 
 CHAPTER III. 
 
 TIIK AMOUNT OF FINE EARTH BROUGHT UP BY WORMS 
 TO THE SURFACE. 
 
 Rate at which various objects strewed on the surface of 
 grass-fields are covered up by the castings of worms 
 The burial of a paved path The slow subsidence 
 of great stones left on the surface The number of 
 worms which live within a given space The
 
 CONTENTS. v 
 
 weight of earth ejected from a burrow, and from all 
 the burrows within a given space The thickness 
 of the layer of mould which the castings on a given 
 space would form within a given time if uniformly 
 spread out The slow rate at which mould can 
 increase to a great thickness Conclusion. 
 
 Pages 131-177 
 
 CHAPTEK IV. 
 
 THE PART WHICH WORMS HAVE PLAYED IN THE 
 BURIAL OF ANCIENT BUILDINGS. 
 
 The accumulation of rubbish on the sites of great cities 
 independent of the action of worms The burial of 
 a Eoman villa at Abinger The floors and walls 
 penetrated by worms Subsidence of a modern 
 pavement The buried pavement at Beaulieu Abbey 
 Koman villas at Chedworth and Brad ing The 
 remains of the Eoman town at Silchester The 
 nature of the debris by which the remains are 
 covered The penetration of the tesselated floors 
 and walls by worms Subsidence of the floors 
 Thickness of the mould The old Eoman city of 
 Wroxeter Thickness of the mould Depth of the 
 foundations of some of the buildings Conclusion. 
 
 178-231 
 
 CHAPTEE V. 
 
 THE ACTION OF WORMS IN THE DENUDATION OF 
 THE LAND. 
 
 Evidence of the amount of denudation which the land 
 ' has undergone Sub-aerial denudation The deposi- 
 tion of dust Vegetable mould, its dark colour and
 
 CONTEXTS. 
 
 fine texture largely due to the action of worms 
 The disintegration of rocks by the humus-acids 
 Similar acids apparently generated within the 
 bodies of worms The action of these acids facilitated 
 by the continued movement of the particles of earth 
 A thick bed of mould checks the disintegration 
 of the underlying soil and rocks Particles of stone 
 worn or triturated in the gizzards of worms 
 Swallowed stones serve as millstones The levigated 
 state of the castings Fragments of brick in the 
 castings over ancient buildings well rounded. The 
 triturating power of worms not quite insignificant 
 under a geological point of view . Pages 232-261 
 
 CHAPTER VI. 
 
 THE DENUDATION OF THE LAND Continued. 
 
 Denudation aided by recently ejected castings flowing 
 down inclined grass-covered surfaces The amount 
 of earth which annually flows downwards The 
 effect of tropical rain on worm-castings The finest 
 particles of earth washed completely away from 
 castings The disintegration of dried castings into 
 pellets, and their rolling down inclined surfaces 
 The formation of little ledges on hill-sides, in part 
 due to the accumulation of disintegrated castings 
 Castings blown to leeward over level land An 
 attempt to estimate the amount thus blown The 
 degradation of ancient encampments and tumuli 
 The preservation of the crowns and furrows on land 
 anciently ploughed The formation and amount of 
 mould over the Chalk formation . 262-307
 
 CONTENTS. vii 
 
 CHAPTER VII. 
 
 CONCLUSION. 
 
 Summary of the part which worms have played iu the 
 history of the world Their aid in the disintegra- 
 tion of rocks In the denudation of the land In 
 the preservation of ancient remains In the pre- 
 paration of the soil for the growth of plants 
 Mental powers of worms Conclusion. 
 
 Pages 308-316 
 
 LNDEX ....... 317-328
 
 THE 
 
 FORMATION OF VEGETABLE MOUL1>, 
 
 THROUGH THE ACTION OF WORMS, WITH 
 OBSERVATIONS OX THEIR HABITS. 
 
 INTRODUCTION. 
 
 THE share which worms have taken in the 
 formation of the layer of vegetahle mould,, 
 which covers the whole surface of the land 
 in every moderately humid country, is the 
 subject of the present volume. This mould 
 is generally of a blackish colour and a few 
 inches in thickness. In different districts it 
 differs but little in appearance, although ' it 
 may rest on various subsoils. The uniform* 
 fineness of the particles of which it is com- 
 posed is one of its chief characteristic features ; 
 and this may be well observed in any gravelly 
 country, where a recently-ploughed field 
 
 B
 
 2 INTRODUCTION. 
 
 immediately adjoins one which has long re- 
 mained undisturbed for pasture, and where 
 the vegetable mould is exposed on the sides 
 of a ditch or hole. The subject may appear 
 an insignificant one, but we shall see that 
 it possesses some interest; and the maxim 
 "de minimis non curat lex," does not apply 
 to science. Even Elie de Beaumont, who 
 generally undervalues small agencies and 
 their accumulated effects, remarks : * "La 
 " couche tres-mince de la terre ve'getale est un 
 " monument d'une haute antiquite', et, par le 
 " fait de sa permanence, un objet digne d'oc- 
 " cuper le geologue, et capable de lui fournir 
 ' ; des remarques inte'ressantes." Although 
 the superficial layer of vegetable mould as a 
 whole no doubt is of the highest antiquity, 
 yet in regard to its permanence, we shall here- 
 after see reason to believe that its component 
 particles are in most cases removed at not a 
 very slow rate, and are replaced by others 
 due to the disintegration of the underlying 
 materials. 
 
 As I was led to keep in my study during 
 many months worms in pots filled with earth, 
 
 * ' Lc9ons de Geologic Pratique,' torn. i. 1845, p. 140.
 
 INTRODUCTION. 3 
 
 I became interested in them, and wished to 
 learn how far they acted consciously, and how 
 much mental power they displayed. I was 
 the more desirous to learn something on this 
 head, as few observations of this kind have 
 been made, as far as I know, on animals so 
 low in the scale of organization and so 
 poorly provided with sense-organs, as are 
 earth-worms. 
 
 In the year 1837, a short paper was read 
 by me before the Greological Society of 
 London,* " On the Formation of Mould," in 
 which it was shown that small fragments of 
 burnt marl, cinders, &c., which had been 
 thickly strewed over the surface of several 
 meadows, were found after a few years lying 
 :at the depth of some inches beneath the turf, 
 but still forming a layer. This apparent 
 sinking of superficial bodies is due, as 
 was first suggested to me by Mr. Wedgwood 
 of Maer Hall in Staffordshire, to the large 
 quantity of fine earth continually brought 
 up to the surface by worms in the form of 
 castings. These castings are sooner or later 
 
 * ' Transactions Geolog. Soc.' vol. v. p. 505. Read Novem- 
 ber 1, 1837. 
 
 B 2
 
 4 INTRODUCTION. 
 
 spread out and cover up any object left on 
 the surface. I was thus led to conclude that 
 all the vegetable mould over the whole coun- 
 try has passed many times through, and will 
 again pass many times through, the intestinal 
 canals of worms. Hence the term "animal 
 mould " would be in some respects more 
 appropriate than that commonly used of 
 '* vegetable mould." 
 
 Ten years after the publication of my paper, 
 M. D'Archiac, evidently influenced by the doc- 
 trines of Elie de Beaumont, wrote about my 
 "singuliere the'orie," and objected that it could 
 apply only to "les prairies basses et humides;" 
 and that "les terres laboure'es, les bois, les 
 prairies e'leve'es, n'apportent aucune preuve 
 a 1'appui de cette maniere de voir." * But M. 
 D'Archiac must have thus argued from inner 
 consciousness and not from observation, for 
 worms abound to an extraordinary degree in 
 kitchen gardens where the soil is continually 
 worked, though in such loose soil they generally 
 deposit their castings in any open cavities or 
 within their old burrows instead of on the 
 surface. Hensen estimates that there are 
 
 * ' Histoire des progrfcs du la Geologic,' torn. i. 1847, p. 221
 
 INTRODUCTION. 5 
 
 about twice as many worms in gardens as in 
 corn-fields.* "With respect to "prairies 
 elevees," I do not know how it may be in 
 France, but nowhere in England have I seen 
 the ground so thickly covered with castings 
 as on commons, at a height of several hundred 
 feet above the sea. In woods again, if the loose 
 leaves in autumn are removed, the whole 
 surface will be found strewed with castings. 
 Dr. King, the superintendent of the Botanic 
 Garden in Calcutta, to whose kindness I am 
 indebted for many observations on earth- 
 worms, informs me that he found, near Nancy 
 in France, the bottom of the State forests 
 covered over many acres with a spongy layer, 
 composed of dead leaves and innumerable 
 worm-castings. He there heard the Professor 
 of " Amenagement des Forets " lecturing to 
 his pupils, and pointing out this case as a 
 " beautiful example of the natural cultiva- 
 *' tion of the soil ; for year after year the 
 <; thrown-up castings cover the dead leaves ; 
 "the result being a rich huznus of great 
 " thickness." 
 
 * 'Zeitschrift fiir wissenschaft. Zoologie,' B. xxviii. 1877, 
 p. 361.
 
 INTRODUCTION. 
 
 In the year 1869, Mr. Fish* rejected my 
 conclusions with respect to the part which 
 worms have played in the formation of veget- 
 ahle mould, merely on account of their assumed 
 incapacity to do so much work. He remarks 
 that "considering their weakness and their 
 " size, the work they are represented to 
 " have accomplished is stupendous." Here we 
 have an instance of that inability to sum 
 up the effects of a continually recurrent 
 cause, which has often retarded the progress 
 of science, as formerly in the case of geology, 
 and more recently in that of the principle 
 of evolution. 
 
 Although these several objections seemed 
 to me to have no weight, yet I resolved to 
 make more observations of the same kind as 
 those published, and to attack the problem on 
 another side ; namely, to weigh all the cast- 
 ings thrown up within a given time in a 
 measured space, instead of ascertaining the 
 rate at which objects left on the surface were 
 buried by worms. But some of my ob- 
 servations have been rendered almost super- 
 fluous by an admirable paper by Hensc:i r 
 
 * ' Gardeners' Chronicle,' April 17, 18G9, p. 418.
 
 INTRODUCTION. 7 
 
 already alluded to, which appeared in 1877.* 
 Before entering on details with respect to the 
 castings, it will be advisable to give some 
 account of the habits of worms from my 
 own observations and from those of other 
 naturalists. 
 
 * Mr. Darwin's attention was called by Professor Hensen to 
 P. E. Miiller's work on Humus in ' Tidsskrift for Skovbrug,' 
 Band iii. Heft 1 and 2, Copenhagen, 1878. He had, however, 
 no opportunity of consulting Miiller's work. Dr. Miiller pub- 
 lished a second paper in 1884 in the same periodical a Danish 
 journal of forestry. His results have also been published in 
 German, in a volume entitled ' Studien iiber die nattirlichen 
 Humusformen, unter deren Einwirkung auf Vegetation und 
 Boden,' 8vo., Berlin, 1887. 
 
 [FIRST EDITION, 
 
 October 10th, 1881.]
 
 HABITS OF WORMS. CHAP. I. 
 
 CHAPTER I. 
 
 HABITS OF WORMS. 
 
 Nature of the sites inhabited Can live long under water- 
 Nocturnal Wander about at night Often lie close to the 
 mouths of their burrows, and are thus destroyed in large 
 numbers by birds Structure Do not possess eyes, but can 
 distinguish between light and darkness Retreat rapidly when 
 brightly illuminated, not by a reflex action Power of attention 
 Sensitive to heat and cold Completely deaf Sensitive to 
 vibrations and to touch Feeble power of smell Taste 
 Mental qualities Nature of food Omnivorous Digestion 
 Leaves before being swallowed, moistened with a fluid of the 
 nature of the pancreatic secretion Extra-stomachal digestion 
 Calciferous glands, structure of Calcareous concretions 
 formed in the anterior pair of glands The calcareous matter 
 primarily an excretion, but secondarily serves to neutralise the 
 acids generated during the digestive process. 
 
 EARTH-WORMS are distributed throughout the 
 world under the form of a few genera, which 
 externally are closely similar to one another. 
 The British species of Lumbricus have never 
 been carefully monographed; but we may 
 judge of their probable number from those 
 inhabiting neighbouring countries. In Scan- 
 dinavia there are eight species, according to
 
 CHAP. I. SITES INHABITED. 9 
 
 Eisen ;* but two of these rarely burrow in the 
 ground, and one inhabits very wet places or 
 even lives under the water. We are here 
 concerned only with the kinds which bring 
 up earth to the surface in the form of cast- 
 ings. Hoffmeister says that the species in 
 Germany are not well known, but gives the 
 same number as Eisen, together with some 
 strongly marked varieties.f 
 
 Earth-worms abound in England in many 
 different stations. Their castings may be 
 seen in extraordinary numbers on commons 
 and chalk-downs, so as almost to cover the 
 whole surface, where the soil is poor and the 
 grass short and thin. But they are almost or 
 quite as numerous in some of the London 
 parks, where the grass grows well and the 
 soil appears rich. Even on the same field 
 worms are much more frequent in some places 
 than in others, without any visible difference 
 in the nature of the soil. They abound in 
 paved court-yards close to houses ; and an 
 instance will be given in which they had 
 
 * ' Bidrag till Skandinaviens Oligoclifetfauna,' 1871. 
 t ' Die bis jetzt bekannten Arten aus der Familie der Begen- 
 \viirmcr,' 1845.
 
 10 HABITS OF AVOIUIS. CHAP. I. 
 
 burrowed through the floor of a very damp 
 cellar. I have seen worms in black peat in a 
 boggy field ; but they are extremely rare, or 
 quite absent in the drier, brown, fibrous peat, 
 which is so much valued by gardeners. On 
 dry, sandy or gravelly tracks, where heath 
 with some gorse, ferns, coarse grass, moss and 
 lichens alone grow, hardly any worms can 
 be found. But in many parts of England, 
 wherever a path crosses a heath, its surface 
 becomes covered with a fine short sward. 
 Whether this change of vegetation is due to 
 the taller plants being killed by the occasional 
 trampling of man and animals, or to the soil 
 being occasionally manured by the droppings 
 from animals, I do not know.* On such 
 grassy paths worm-castings may often be seen. 
 On a heath in Surrey, which was carefully 
 examined, there were only a few castings on 
 these paths, where they were much inclined ; 
 
 * There is even some reason to believe that pressure is actually 
 favourable to the growth of grasses, for Professor Buckman, who 
 made many observations on their growth in the experimental, 
 gardens of the Royal Agricultural College, remarks (' Gardeners' 
 Chronicle,' 1854, p. 619) : " Another circumstance in the cultiva- 
 tion of grasses in the separate form or small patches, is the 
 impossibility of rolling or treading them firmly, without which 
 no pasture can continue good."
 
 CHAP. I. SITES INHABITED. II 
 
 but on the more level parts, where a bed of 
 fine earth had been washed down from the 
 steeper parts and had accumulated to a thick- 
 ness of a few inches, worm-castings abounded. 
 These spots seemed to be overstocked with 
 worms, so that they had been compelled to 
 spread to a distance of a few feet from the 
 grassy paths, and here their castings had been 
 thrown up among the heath ; but beyond this 
 limit, not a single casting could be found. A 
 layer, though a thin one, of fine earth, which 
 probably long retains some moisture, is in 
 all cases, as I believe, necessary for their 
 existence ; and the mere compression of the 
 soil appears to be in some degree favourable 
 to them, for they often abound in old gravel 
 walks, and in foot-paths across fields. 
 
 Beneath large trees few castings can be 
 found during certain seasons of the year, and 
 this is apparently due to the moisture having 
 been sucked out of the ground by the innu- 
 merable roots of the trees ; for such places 
 may be seen covered with castings after the 
 heavy autumnal rains. Although most cop- 
 pices and woods support many worms, yet in a 
 forest of tall and ancient beech-trees in Knole
 
 12 HABITS OF WOEMS. CHAP. I. 
 
 Park, where the ground beneath was bare of 
 all vegetation, not a single casting could be 
 found over wide spaces, even during the 
 autumn. Nevertheless, castings were abun- 
 dant on some grass-covered glades and in- 
 dentations which penetrated this forest. On 
 the mountains of North Wales and on the 
 Alps, worms, as I have been informed, are in 
 most places rare ; and this may perhaps be 
 due to the close proximity of the sub- 
 jacent rocks, into which worms cannot 
 burrow during the winter so as to escape 
 being frozen. Dr. Mclntosh, however, found 
 worm-castings at a height of 1500 feet on 
 Schiehallion in Scotland. They are numerous 
 on some hills near Turin at from 2000 to 
 3000 feet above the sea, and at a great 
 altitude on the Nilgiri Mountains in South 
 India and on the Himalaya 
 
 Earth-worms must be considered as terres- 
 trial animals, though they are still in one 
 sense semi-aquatic, like the other members of 
 the great class of annelids to which they 
 belong. M. Perrier found that their ex- 
 posure to the dry air of a room for only a 
 single night was fatal to them. On the
 
 CHAP. I. NOCTUKNAL. 13 
 
 other hand he kept several large worms alive 
 for nearly four months, completely submerged 
 in water.* During the summer when the 
 ground is dry, they penetrate to a consider- 
 able depth and cease to work, as they do 
 during the winter when the ground is frozen. 
 Worms are nocturnal in their habits, and at 
 night may be seen crawling about in large 
 numbers, but usually with their tails still 
 inserted in their burrows. By the expansion 
 of this part of their bodies, and with the help 
 of the short, slightly reflexed bristles, with 
 which their bodies are armed, they hold 
 so fast that they can seldom be dragged 
 out of the ground without being torn into 
 pieces.f During the day they remain in 
 their burrows, except at the pairing season, 
 when those which inhabit adjoining burrows 
 expose the greater part of their bodies for 
 an hour or two in the early morning. Sick 
 
 * I shall have occasion often to refer to M. Perrier's admirable 
 memoir, ' Organisation des Lombriciens terrestres ' in ' Archives 
 de Zoolog. expe'r.' torn. iii. 1874, p. 372. C. F. Morren (' De 
 Luinbrici terrestris Hist. Nat.' 1829, p. 14) found that worms 
 endured immersion for fifteen to twenty days in summer, but 
 that in winter they died when thus treated. 
 
 t Morren, 'De Lumbrici terrestris Hist. Nat.' &c., 1829, 
 p. 67.
 
 14 HABITS OF WORMS. CHAP. I. 
 
 individuals, which are generally affected by 
 the parasitic larvae of a fly, must also be ex- 
 cepted, as they wander about during the day 
 and die on the surface. After heavy rain 
 succeeding dry weather, an astonishing num- 
 ber of dead worms may sometimes be seen 
 lying on the ground. Mr. Galton informs 
 me that on one such occasion (March, 1881), 
 the dead worms averaged one for every 
 two and a half paces in length on a walk in 
 Hyde Park, four paces in width. He counted 
 no less than 45 dead worms in one place in 
 a length of sixteen paces. From the facts 
 above given, it is not probable that these 
 worms could have been drowned, and if they 
 had been drowned they would have perished 
 in their burrows. I believe that they were 
 already sick, and that their deaths were 
 merely hastened by the ground being flooded. 
 It has often been said that under ordinary 
 circumstances healthy worms never, or very 
 rarely, completely leave their burrows at 
 night ; but this is an error, as White of Sel- 
 borne long ago knew. In the morning, after 
 there has been heavy rain, the film of mud 
 or of very fine sand over gravel-walks is often
 
 CHAP. I. WANDER FROM THEIR BURROWS. 15 
 
 plainly marked with their tracks. I have 
 noticed this from August to May, both months 
 included, and it probably occurs during the 
 two remaining months of the year when 
 they are wet. On these occasions, very few 
 dead worms could anywhere be seen. On 
 January 31, 1881, after a long-continued 
 and unusually severe frost with much snow, 
 as soon as a thaw set in, the walks were 
 marked with innumerable tracks. On one 
 occasion, five tracks were counted crossing 
 a space of only an inch square. They could 
 sometimes be traced either to or from the 
 mouths of the burrows in the gravel-walks, 
 for distances between 2 or 3 up to 15 yards. 
 I have never seen two tracks leading to the 
 same burrow ; nor is it likel}~, from what we 
 shall presently see of their sense-organs, that 
 a worm could find its way back to its burrow 
 after having once left it. They apparently 
 leave their burrows on a voyage of discovery, 
 and thus they find new sites to inhabit. 
 
 Morren states * that worms often lie for 
 hours almost motionless close beneath the 
 mouths of their burrows. I have occasionally 
 noticed the same fact with worms kept in 
 
 * ' De Lumbrici terrestris Hist. Nat.' &c., p. 14.
 
 16 HABITS OF WORMS. CHAP. I. 
 
 pots in the house ; so that hy looking down 
 into their burrows, their heads could just be 
 seen. If the ejected earth or rubbish over 
 the burrows be suddenly removed, the end 
 of the worm's body may very often be seen 
 rapidly retreating. This habit of lying near 
 the surface leads to their destruction to an 
 immense extent. Every morning during cer- 
 tain seasons of the year, the thrushes and 
 blackbirds on all the lawns throughout the 
 country draw out of their holes an astonishing 
 number of worms ; and this they could not 
 do, unless they lay close to the surface. It 
 is not probable that worms behave in this 
 manner for the sake of breathing fresh air, 
 for we have seen that they can live for a 
 long time under water. I believe that they lie 
 near the surface for the sake of warmth, es- 
 pecially in the morning ; and we shall here- 
 after find that they often coat the mouths 
 of their burrows with leaves, apparently to 
 prevent their bodies from coming into close 
 contact with the cold damp earth. It is said 
 that they completely close their burrows 
 during the winter. 
 
 Structure. A few remarks must be made 
 on this subject. The body of a large worm
 
 CHAP. I. THEIR STRUCTURE. 17 
 
 consists of from 100 to 200 almost cylindrical 
 rings or segments, each furnished with minute 
 bristles. The muscular system is well 
 developed. Worms can crawl backwards as 
 well as forwards, and by the aid of their 
 affixed tails can retreat with extraordinary 
 rapidity into their burrows. The mouth is 
 situated at the anterior end of the body, and 
 is provided with a little projection (lobe or lip, 
 as it has been variously called) which is used 
 for prehension. Internally, behind the mouth, 
 there is a strong pharynx, shown in the ac- 
 .companying diagram (Fig. 1) which is pushed 
 forwards when the animal eats, and this part 
 corresponds, according to Perrier, with the pro- 
 trudable trunk or proboscis of other annelids. 
 The pharynx leads into the oesophagus, on 
 each side of which in the lower part there 
 are three pairs of large glands, which secrete 
 a surprising amount of carbonate of lime. 
 These calciferous glands are highly remark- 
 able, for nothing like them is known in any 
 other animal. Their use will be discussed 
 when we treat of the digestive process. In 
 most of the species, the oesophagus is enlarged 
 into a crop in front of the gizzard. This 
 
 c
 
 18 
 
 HABITS OF WORMS. 
 
 CHAP. I. 
 
 latter organ is lined with a smooth thick 
 chitinous membrane, and 
 is surrounded by weak 
 longitudinal, but power- 
 ful transverse muscles. 
 Perrier saw these muscles 
 in energetic action; and, as 
 he remarks, the trituratioii 
 of the food must be chiefly 
 effected by this organ, for 
 worms possess no jaws or 
 teeth of any kind. Grains 
 of sand and small stones, 
 from the -^ to a little 
 more than the -^ inch in 
 diameter, may generally 
 be found in their gizzards 
 and intestines. As it is 
 certain that worms swal- 
 low many little stones, in- 
 
 Diogmmrf the alimen- dependency of those swal- 
 lowed while excavating 
 burrows, it is prob- 
 
 Mout'a. 
 
 Pharynx. 
 
 (Esophagus. 
 
 Calc'ferous glands. 
 
 (Esophagus. 
 
 Crop. 
 
 Upper part of in- 
 testine. 
 
 tary canal of an earth- 
 worm (Lumbricus), 
 copied from 1'ay Lan- 
 
 kcster in 'Quart, able that they serve, like 
 m iii_ st ones, to triturate 
 
 . ' 
 
 their food. The gizzard 
 opens into the intestine, 
 
 Journ. of Microscop. 
 Sc.' vol. xv. N.S. 
 pi. vii.
 
 CHAP. I. THEIK SENSES. 19 
 
 which runs in a straight course to the vent 
 at the posterior end of the body. The intes- 
 tine presents a remarkable structure, the 
 typhlosolis, or, as the old anatomists called 
 it, an intestine within an intestine ; and Cla- 
 parede * has shown that this consists of a 
 deep longitudinal involution of the walls of 
 the intestine, by which means an extensive 
 absorbent surface is gained. 
 
 The circulatory system is well developed. 
 "Worms breathe by their skin, as they do not 
 possess any special respiratory organs. The 
 two sexes are united in the same individual, but 
 two individuals pair together. The nervous 
 system is fairly well developed ; and the two 
 almost confluent cerebral ganglia are situated 
 very near to the anterior end of the body. 
 
 Senses. Worms are destitute of eyes, and 
 at first I thought that they were quite in- 
 sensible to light ; for those kept in confine- 
 ment were repeatedly observed by the aid of 
 a candle, and others out of doorS by the aid 
 of a lantern, yet they were rarely alarmed, 
 although extremely timid animals. Other 
 
 * Histolog. Untersuchungen iiber die Regenwiirmer. 'Zeit- 
 scbrift fur wissenschaft. Zoologie,' B. six., 1869, p. 611. 
 
 c 2
 
 20 HABITS OF WORMS. CHAP. I. 
 
 persons have found no difficulty in observing 
 worms at night by the sanie means.* 
 
 Hoffmeister, however, states f that worms, 
 with the exception of a few individuals, are 
 extremely sensitive to light ; but he admits 
 that in most cases a certain time is requisite 
 for its action. These statements led me to 
 watch on many successive nights worms kept 
 in pots, which were protected from currents 
 of air by means of glass plates. The pots 
 were approached very gently, in order that 
 no vibration of the floor should be caused. 
 When under these circumstances worms were 
 illuminated by a bull's-eye lantern having 
 slides of dark red and blue glass, which in- 
 tercepted so much light that they could be seen 
 only with some difficulty, they were not at all 
 affected by this amount of light, however long 
 they were exposed to it. The light, as far 
 as I could judge, was brighter than that from 
 the. full moon. Its colour apparently made 
 no difference* in the result. When they were 
 
 * For, instance, Mr. Bridgman and Mr. Newman ('The 
 Zoologist,' vol. vii. 1849, p. 2576), and some friends who observed 
 worms for me. 
 
 f ' Familie der Regenwiirmer.' 1845, p. 18.
 
 CHAP. I. THEIR SENSES. 21" 
 
 illuminated by a candle, or even by a bright 
 paraffin lamp, they were not usually affected 
 at first. Nor were they when the light was- 
 alternately admitted and shut off. Some- 
 times, however, they behaved very differ- 
 ently, for as soon as the light fell on them, 
 they withdrew into their burrows with 
 almost instantaneous rapidity. This occurred 
 perhaps once out of a dozen times. When 
 they did not withdraw instantly, they often 
 raised the anterior tapering ends of their 
 bodies from the ground, as if their attention- 
 was aroused or as if surprise was felt ; or 
 they moved their bodies from side to side as- 
 if feeling for some object. They appeared 
 distressed by the light ; but I doubt whether 
 this was really the case, for on two occasions 
 after withdrawing slowly, they remained for 
 a long time with their anterior extremities 
 protruding a little from the mouths of their 
 burrows, in which position they were ready 
 for instant and complete withdrawal. 
 
 "When the light from a candle was con- 
 centrated by means of a large lens on the 
 anterior extremity, they generally withdrew 
 instantly ; but this concentrated light failed
 
 22 HABITS OF WORMS. CHAP. T. 
 
 to act perhaps once out of half a dozen trials. 
 The light was on one occasion concentrated 
 6>n a worm lying beneatli water in a saucer, 
 and it instantly withdrew into its burrow. 
 In all cases the duration of the light, unless 
 extremely feeble, made a great difference in 
 the result; for worms left exposed before a 
 paraffin lamp or a candle invariably retreated 
 into their burrows within from five to fifteen 
 minutes ; and if in the evening the pots were 
 illuminated before the worms had come out of 
 their burrows, they failed to appear. 
 
 From the foregoing facts it is evident that 
 light affects worms by its intensity and by 
 its duration. It is only the anterior 
 extremity of the body, where the cerebral 
 ganglia lie, which is affected by light, as 
 Hoffmeister asserts, and as I observed on 
 many occasions. If this part is shaded, other 
 parts of the body may be fully illuminated, 
 and no effect will be produced. As these 
 animals have no eyes, we must suppose that 
 the light passes through their skins, and in 
 some manner excites their cerebral ganglia. 
 It appeared at first probable that the dif- 
 ferent manner in which they were affected on
 
 <JIIAP. I. THEIR SENSES. 23 
 
 different occasions might be explained, either 
 by the degree of extension of their skin and 
 its consequent transparency, or by some 
 particular incidence of the light ; but I 
 could discover no such relation. One thing 
 was manifest, namely, that when worms were 
 employed in dragging leaves into their 
 burrows or in eating them, and even during 
 the short intervals whilst they rested from 
 their work, they either did not perceive 
 the light or were regardless of it ; and this 
 occurred even when the light was concentrated 
 on them through a large lens. So, again, 
 whilst they are paired, they will remain for 
 an hour or two out of their burrows, fully 
 exposed to the morning light ; but it appears 
 from what Hoffmeister says that a light 
 will occasionally cause paired individuals to 
 separate. 
 
 When a worm is suddenly illuminated and 
 dashes like a rabbit into its burrow to use 
 the expression employed by a friend we are 
 at first led to look at the action as a reflex one. 
 The irritation of the cerebral ganglia appears 
 to cause certain muscles to contract in an 
 inevitable manner, independently of the will
 
 24 HABITS OF WORMS. CHAP. I. 
 
 or consciousness of the animal, as if it were 
 an automaton. But the different effect 
 which a light produced 011 different occasions, 
 and especially the fact that a worm when in 
 any way employed and in the intervals of 
 such employment, whatever set of muscles 
 and ganglia may then have been brought into 
 play, is often regardless of light, are opposed 
 to the view of the sudden withdrawal being 
 a simple reflex action. With the higher 
 animals, when close attention to some object 
 leads to the disregard of the impressions 
 which other objects must be producing on 
 them, we attribute this to their attention 
 being then absorbed ; and attention implies 
 the presence of a mind. Every sportsman 
 knows that he can approach animals whilst 
 they are grazing, fighting or courting, much 
 more easily than at other times. The state, 
 also, of the nervous system of the higher 
 animals differs much at different times, for 
 instance, a horse is much more readily startled 
 at one time than at another. The comparison 
 here implied between the actions of one ot 
 the higher animals and of one so low in the 
 scale as an earth-worm, may appear far-
 
 CHAP. I. THEIR SENSES. 25 
 
 fetched ; for we thus attribute to the worm 
 attention and some mental power, neverthe- 
 less I can see no reason to doubt the justice 
 of the comparison. 
 
 Although worms cannot be said to possess 
 the power of vision, their sensitiveness to 
 light enables them to distinguish between 
 day and night ; and they thus escape extreme 
 danger from the many diurnal animals which 
 prey on them. Their withdrawal into their 
 burrows during the day appears, however, 
 to have become an habitual action; for 
 worms kept in pots covered by glass-plates, 
 over which sheets of black paper were 
 spread, and placed before a north-east win- 
 dow, remained during the day-time in their 
 burrows and came out every night ; and they 
 continued thus to act for a week. No doubt 
 a little light may have entered between the 
 sheets of glass and the blackened paper ; 
 but we know from the trials with coloured 
 glass, that worms are indifferent to a small 
 amount of light. 
 
 Worms appear to be less sensitive to 
 moderate radiant heat than to a bright light. 
 I judge of this from having held at different
 
 26 HABITS OP TVOKMS. CHAP. I, 
 
 times a poker heated to dull redness near 
 some worms, at a distance which caused a 
 very sensible degree of warmth in my hand. 
 One of them took no notice ; a second with- 
 drew into its burrow, but not quickly ; the 
 third and fourth much more quickly, and the 
 fifth as quickly as possible. The light from 
 a candle, concentrated by a lens and passing- 
 through a sheet of glass which would intercept 
 most of the heat-rays, generally caused a 
 much more rapid retreat than did the heated 
 poker. Worms are sensitive to a low temper- 
 ature, as may be inferred ' from their not 
 coming out of their burrows during a frost. 
 
 Worms do not possess any sense of hearing. 
 They took not the least notice of the shrill 
 notes from a metal whistle, which was re- 
 peatedly sounded near them ; nor did they 
 of the deepest and loudest tones of a bassoon. 
 They were indifferent to shouts, if care was 
 taken that the breath did not strike them. 
 When placed on a table close to the keys of 
 a piano, which was played as loudly as 
 possible, they remained perfectly quiet. 
 
 Although they are indifferent to undula- 
 tions in the air audible by us, they are
 
 CHAP. I. THEIR SENSES. 27 
 
 extremely sensitive to vibrations in any solid 
 object. When the pots containing two 
 worms which had remained quite indifferent 
 to the sound of the piano, were placed on 
 this instrument, and the note C in the bass 
 elef was struck, both instantly retreated into 
 their burrows. After a time they emerged, 
 and when Gr above the line in the treble clef 
 was struck they again retreated. Under 
 similar circumstances on another night one 
 worm dashed into its burrow on a very high 
 note being struck only once, and the other 
 worm when C in the treble clef was struck. 
 On these occasions the worms were not 
 touching the sides of the pots, which stood 
 in saucers ; so that the vibrations, before 
 reaching their bodies, had to pass from the 
 sounding board of the piano, through the 
 saucer, the bottom of the pot and the damp, 
 not very compact earth on which they lay 
 with their tails in their burrows. They 
 often showed their sensitiveness when the 
 pot in which they lived, or the table on 
 which the pot stood, was accidentally and 
 lightly struck; but they appeared less sensi- 
 tive to such jars than to the vibrations of the
 
 28 HABITS OF WORMS. CHAP. I. 
 
 piano ; and their sensitiveness to jars varied 
 much at different times. 
 
 It has often been said that if the ground is 
 beaten or otherwise made to tremble, worms 
 believe that they are pursued by a mole 
 and leave their burrows. From one account 
 that I have received, I have no doubt that 
 this is often the case; but a gentleman 
 informs me that he lately saw eight or ten 
 worms leave their burrows and crawl about 
 the grass on some boggy land on which two 
 men had just trampled while setting a trap ; 
 and this occurred in a part of Ireland where 
 there were no moles. I have been assured 
 by a Volunteer that he has often seen many 
 large earth-worms crawling quickly about 
 the grass, a few minutes after his company 
 had fired a volley with blank cartridges. The 
 Peewit (Tringavanellus, Linn.) seems to know 
 instinctively that worms will emerge if the 
 ground is made to tremble ; for Bishop 
 Stanley states (as I hear from Mr. Moorhouse) 
 that a young peewit kept in confinement used 
 to stand on one leg and beat the turf with 
 the other leg until the worms crawled out 
 of their burrows, when they were instantly
 
 CHAP. I. THEIR SENSES. 29 
 
 devoured. Nevertheless, worms do not in- 
 variably leave their burrows when the ground 
 is mcide to tremble, as I know by having 
 beaten it .with a spade, but perhaps it was 
 beaten too violently. 
 
 The whole body of a worm is sensitive to 
 contact. A slight puff of air from the mouth 
 causes an instant retreat. The glass plates 
 placed over the pots did not fit closely, and 
 blowing through the very narrow chinks thus 
 left, often sufficed to cause a rapid retreat. 
 They sometimes perceived the eddies in the 
 air caused by quickly removing the glass 
 plates. When a worm first comes out of its 
 burrow, it generally moves the much ex- 
 tended anterior extremity of its body from 
 side to side in all directions, apparently as an 
 organ of touch ; and there is some reason to 
 believe, as we shall see in the next chapter, 
 that they are thus enabled to gain a general 
 notion of the form of an object. Of all their 
 senses that of touch, including in this term 
 the perception of a vibration, seems much the 
 most highly developed. 
 
 In worms the sense of smell apparently is 
 confined to 'the. perception, of certain odours,
 
 30 HABITS OF WORMS. CHAP. I. 
 
 and is feeble. They were quite indifferent to 
 my breath, as long" as I breathed on them very 
 gently. This was tried, because it appeared 
 possible that they might thus be warned of 
 the approach of an enemy. They exhibited, 
 the same indifference to my breath whilst I 
 chewed some tobacco, and while a pellet of 
 cotton-wool with a few drops of millefleurs 
 perfume or of acetic acid was kept in my 
 mouth. Pellets of cotton-wool soaked in 
 tobacco juice, in millefleurs perfume, and in 
 paraffin, were held with pincers and were 
 waved about within two or three inches of 
 several worms, but they took no notice. On 
 one or two occasions, however, when acetic 
 acid had been placed on the pellets, the worms 
 appeared a little uneasy, and this was 
 probably due to the irritation of their skins. 
 The perception of such unnatural odours 
 would be of no service to worms ; and as such 
 timid creatures would almost certainly exhibit 
 some signs of any new impression, we may 
 conclude that they did not perceive these 
 odours. 
 
 The result was different when cabbage- 
 leaves and pieces of onion were employed,
 
 CHAP. I. THEIR SENSES. 31 
 
 both of which are devoured with much relish 
 by worms. Small square pieces of fresh and 
 half-decayed cabbage-leaves and of onion 
 bulbs were on nine occasions buried in my 
 pots, beneath about i of an inch of common 
 garden soil ; and they were always discovered 
 by the worms. One bit of cabbage was dis- 
 covered and removed in the course of two 
 hours ; three were removed by the next 
 morning, that is, after a single night ; two 
 others after two nights ; and the seventh bit 
 after three nights. Two pieces of onion were 
 discovered and removed after three nights. 
 Bits of fresh raw meat, of which worms are 
 very fond, were buried, and were not dis- 
 covered within forty-eight hours, during 
 which time they had not become putrid. The 
 earth above the various buried objects was 
 generally pressed down only slightly, so as 
 not to prevent the emission of any odour. 
 On two occasions, however, the surface was 
 well watered, and was thus rendered some- 
 what compact. After the bits of cabbage and 
 onion had been removed, I looked beneath 
 them to see whether the worms had acci- 
 dentally come up from below, but there was-
 
 32 HABITS OF WOBMS. CHAP. I. 
 
 no sign of a burrow; and twice the buried 
 objects were laid on pieces of tin-foil which 
 were not in the least displaced. It is of 
 course possible that the worms whilst moving 
 about on the surface of the ground, with their 
 tails affixed within their burrows, may have 
 poked their heads into the places where the 
 above objects were buried ; but I have never 
 seen worms acting in this manner. Some 
 pieces of cabbage-leaf and of onion were twice 
 buried beneath very fine ferruginous sand, 
 w.hich was slightly pressed down and well 
 watered, so as to be rendered very compact, 
 and these pieces were never discovered. On 
 a third occasion the same kind of sand was 
 neither pressed down nor watered, <ind the 
 pieces of cabbage were discovered and re- 
 moved after the second night. These several 
 facts indicate that worms possess some power 
 of smell ; and that they discover by this 
 means odoriferous and much-coveted kinds 
 of food. 
 
 It may be presumed that all animals which 
 feed on various substances possess the sense 
 of taste, and this is certainly the case with 
 worms. Cabbage-leaves are much liked by
 
 CHAP. I. THEIB SENSES. 33- 
 
 worms; and it appears that they can dis- 
 tinguish between different varieties ; but this- 
 may perhaps be owing to differences in their 
 texture. On eleven occasions pieces of the> 
 fresh leaves of a common green variety and 
 of the red variety used for pickling were 
 given them, and they preferred the green, 
 the red being either wholly neglected or much 
 less gnawed. On two other occasions, how- 
 ever, they seemed to prefer the red. Half- 
 decayed leaves of the red variety and fresh 
 leaves of the green were attacked about 
 equally. When leaves of the cabbage, horse- 
 radish (a favourite food) and of the onion were- 
 given together, the latter were always and 
 manifestly preferred. Leaves of the cab- 
 bage, lime-tree, Ampelopsis, parsnip (Pasti- 
 naca), and celery (Apium) were likewise 
 given together; and those of the celery 
 were first eaten. But when leaves of cab- 
 oage, turnip, beet, celery, wild cherry and 
 carrots were given together, the two lattef 
 kinds, especially those of the carrot, were- 
 preferred to all the others, including those 
 of celery. It was also manifest after many 
 trials that wild cherry leaves were greatly 
 
 D
 
 34 HABITS OP WORMS. CHAP. I. 
 
 preferred to those of the lime-tree and hazel 
 (Corylus). According to Mr. Bridgman the 
 half-decayed leaves of Phlox verna are par- 
 ticularly liked by worms.* 
 
 Pieces of the leaves of cabbage, turnip, 
 horse-radish and onion were left on the pots 
 during 22 days, and were all attacked and 
 had to be renewed; but during the whole 
 of this time leaves of an Artemisia and of 
 the culinary sage, thyme and mint, mingled 
 with the above leaves, were quite neglected 
 excepting those of the mint, which were occa- 
 sionally and very slightly nibbled. These 
 latter four kinds of leaves do not differ in 
 texture in a manner which could make them 
 disagreeable to worms; they all have a 
 strong taste, but so have the four first men- 
 tioned kinds of leaves ; and the wide differ- 
 ence in the result must be attributed to a 
 preference by the worms for one taste over 
 another. 
 
 Mental Qualities. There is little to be said 
 on this head. We have seen that worms are 
 timid. It may be doubted whether they 
 suffer as much pain when injured, as they 
 
 * The Zoologist,' vol. vii. 1849, p. 2576.
 
 CHAP. I. MENTAL QUALITIES. 35 
 
 seem to express by their contortions. Judging 
 by their eagerness for certain kinds of food, 
 they must enjoy the pleasure of eating. 
 Their sexual passion is strong enough to 
 overcome for a time their dread of light. 
 'They perhaps have a trace of social feeling, 
 for they are not disturbed by crawling over 
 each other's bodies, and they sometimes lie 
 in contact. According to Hoffmeister they 
 pass the winter either singly or rolled up 
 with others into a ball at the bottom of their 
 burrows.* Although worms are so remark- 
 ably deficient in the several sense-organs, 
 this does not necessarily preclude intelligence, 
 as we know from such cases as those of Laura 
 Bridgman; and we have seen that when their 
 attention is engaged, they neglect impressions 
 to which they would otherwise have attended ; 
 and attention indicates the presence of a mind 
 of some kind. They are also much more 
 easily excited at certain times than at others. 
 They perform a few actions instinctively, that 
 
 * * Familie der Eegenwiirmer,' p. 13. Dr. Sturtevant states 
 in the ' New York Weekly Tribune ' (May 19, 1880) that he kept 
 three worms in a pot, which was allowed to become extremely 
 dry ; and these worms were found " all entwined together, 
 forming a round mass and in good condition." 
 
 D 2
 
 36 HABITS OF WORMS. CHAP. L 
 
 is, all the individuals, including the young, 
 perform such actions in nearly the same 
 fashion. This is shown by the manner in 
 which the species of Pericha3ta eject their 
 castings, so as to construct towers; also by 
 the manner in which the burrows of the 
 common earth-worm are smoothly lined with 
 fine earth and often with little stones, and 
 the mouths of their burrows with leaves. 
 One of their strongest instincts is the plug- 
 ging up the mouths of their barrows with 
 various objects ; and very young worms act 
 in this manner. But some degree of in- 
 telligence appears, as we shall see in the next 
 chapter, to be exhibited in this work, a 
 result which has surprised me more than, 
 anything else in regard to worms. 
 
 Food and Digestion. Worms are omnivo- 
 rous. They swallow an enormous quantity of 
 earth, out of which they extract any diges- 
 tible matter which it may contain ; but to 
 this subject I must recur. They also con- 
 sume a large number of half-decayed leaves 
 of all kinds, excepting a few which have an 
 unpleasant taste or are too tough for them ;. 
 likewise petioles, peduncles, and decayed
 
 CHAP. I. FOOD AND DIGESTION. 37 
 
 flowers. But they will also consume fresh 
 leaves, as I have found by repeated trials. 
 According to Morren * they will eat particles 
 of sugar and liquorice ; and the worms which 
 I kept drew many bits of dry starch into 
 their burrows, and a large bit had its angles 
 well rounded by the fluid poured out of their 
 mouths. But as they often drag particles of 
 soft stone, such as of chalk, into their burrows, 
 I feel some doubt whether the starch was 
 used as food. Pieces of raw and roasted meat 
 were fixed several times by long pins to the 
 surface of the soil in my pots, and night after 
 night the worms could be seen tugging at 
 them, with the edges of the pieces engulfed 
 in their mouths, so that much was consumed. 
 Raw fat seems to be preferred even to raw 
 meat or to any other substance which was 
 given them, and much was consumed. They 
 are cannibals, for the two halves of a dead 
 worm placed in two of the pots were dragged 
 into the burrows and gnawed ; but as far as 
 I could judge, they prefer fresh to putrid 
 meat, and in so far I differ from Hoffmeister. 
 
 * ' DC Lumbrici terrestris Hist. Nat,' p. 19.
 
 38 HABITS OF WORMS. CHAI>. I. 
 
 Leon Fredericq states* that the digestive 
 fluid of worms is of the same nature as the 
 pancreatic secretion of the higher animals ;. 
 and this conclusion agrees perfectly with the 
 kinds of food which worms consume. Pan- 
 creatic juice emulsifies fat, arid we have just 
 seen how greedily worms devour fat ; it 
 dissolves fibrin, and worms eat raw meat ; it 
 converts starch into grape-sugar with wonder- 
 ful rapidity, and we shall presently show that 
 the digestive fluid of worms acts on starch. f 
 But they live chiefly on half-decayed leaves ; 
 and these would be useless to them unless they 
 could digest the cellulose forming the cell- 
 walls ; for it is well known that all other nutri- 
 tious substances are almost completely with- 
 drawn from leaves, shortly before they fall 
 off. It has, however, now been ascertained 
 that some forms of cellulose, though very 
 little or not at all attacked by the gastric 
 
 * Archives de Zoologie expe'rimentale,' torn. vii. 1878, p. 394. 
 When I wrote the above passage, I was not aware that Kruken- 
 berg (' Untersuchungen a. d. physiol. Inst. d. Univ. Heidelberg,' 
 Bd. ii. p. 37, 1877) had previously investigated the digestive 
 juice of Lumbricus. He states that it contains a peptic, and, 
 diastatic, as well as a tryptic ferment. 
 
 t On the action of the pancreatic ferment, see ' A Text-Book 
 of Physiology/ by Michael Foster, 2nd edit. pp. 198-203. 1878.
 
 CHAP. I. FOOD AND DIGESTION. 39 
 
 secretion of the higher animals, are acted on 
 by that from the pancreas.* 
 
 The half-decayed or fresh leaves which 
 worms intend to devour, are dragged into the 
 mouths of their burrows to a depth of from 
 cne to three inches, and are then moistened 
 with a secreted fluid. It has been assumed 
 that this fluid serves to hasten their decay ; 
 but a large number of leaves were twice 
 pulled out of the burrows of worms and kept 
 for many weeks in a very moist atmosphere 
 under a bell-glass in my study ; and the parts 
 which had been moistened by the worms did 
 not decay more quickly in any plain manner 
 than the other parts. When fresh leaves 
 were given in the evening to worms kept in 
 confinement and examined early on the next 
 morning, therefore not many hours after they 
 had been dragged into the burrows, the fluid 
 with which they were moistened, when tested 
 with neutral litmus paper, showed an alkaline 
 reaction. This was repeatedly found to be 
 the case with celery, cabbage and turnip 
 leaves. Parts of the same leaves which had 
 
 * Schmulewitsch, ' Action des Sues digestifs sur la Cellulose.' 
 Bull, de 1'Acad. Imp. de St. Petersbourg, torn. xxv. p. 549. 1879.
 
 (40 HABITS OF WORMS. CHAP. I. 
 
 not been moistened by the worms, were 
 pounded with a few drops of distilled water, 
 and the juice thus extracted was not alkaline. 
 Some leaves, however, which had been drawn 
 into burrows out of doors, at an unknown 
 antecedent period, were tried, and though still 
 moist, they rarely exhibited even a trace of 
 alkaline reaction. 
 
 The fluid, with which the leaves are bathed, 
 acts on them whilst they are fresh or nearly 
 fresh, in a remarkable manner ; for it quickly 
 kills and discolours them. Thus the ends of 
 a fresh carrot-leaf, which had been dragged 
 into a burrow, were found after twelve hours 
 of a dark brown tint. Leaves of celery, 
 turnip, maple, elm, lime, thin leaves of ivy, 
 and occasionally those of the cabbage were 
 similarly acted on. The end of a leaf of 
 Triticum repens, still attached to a growing 
 plant, had been drawn into a burrow, and 
 this part was dark brown and dead, whilst the 
 rest of the leaf was fresh and green. Several 
 leaves of lime and elm removed from burrows 
 out of doors were found affected in different 
 degrees. The first change appears to be that 
 the veins become of a dull reddish-orange.
 
 CHAP. I. FOOD AND DIGESTION. 41 
 
 The cells with chlorophyll next lose more or 
 less completely their green colour, and their 
 contents finally become brown. The parts 
 thus affected often appeared almost black by 
 reflected light ; but when viewed as a trans- 
 parent object under the microscope, minute 
 specks of light were transmitted, arid this 
 was not the case with the unaffected parts 
 of the same leaves. These effects, how- 
 ever, merely show that the secreted fluid is 
 highly injurious or poisonous to leaves ; for 
 nearly the same effects were produced in from 
 one to two days on various kinds of young 
 leaves, not only by artificial pancreatic fluid, 
 prepared with or without thymol, but quickly 
 by a solution of thymol by itself. On one 
 occasion leaves of Corylus were much dis- 
 coloured by being kept for eighteen hours in 
 pancreatic fluid, without any thymol. With 
 young and tender leaves immersion in human 
 saliva during rather warm weather, acted in 
 the same manner as the pancreatic fluid, but 
 not so quickly. The leaves in all these 
 cases often became infiltrated with the 
 fluid. 
 
 Large leaves from an ivy plant growing
 
 42 HABITS OF WORMS. CHAP. I. 
 
 on a wall were so tough that they could not 
 be gnawed by worms, but after four days 
 they were affected in a peculiar manner by the 
 secretion poured out of their mouths. The 
 upper surfaces of the leaves, over which the 
 worms had crawled, as was shown by the dirt 
 left on them, were marked in sinuous lines, 
 by either a continuous or broken chain of 
 whitish and often star-shaped dots, about 
 2 mm. in diameter. The appearance thus pre- 
 sented was curiously like that of a leaf, into 
 which the larva of some minute insect had 
 burrowed. But my son Francis, after making 
 and examining sections, could nowhere find 
 that the cell-walls had been broken down or 
 that the epidermis had been penetrated. 
 When the section passed through the whitish 
 dots, the grains of chlorophyll were seen to 
 be more or less discoloured, and some of the 
 palisade and mesophyll cells contained 
 nothing but broken down granular matter. 
 These effects must be attributed to the trans- 
 udation of the secretion through the epidermis 
 into the cells. 
 
 The secretion with which worms moisten 
 leaves likewise acts on the starch-granules
 
 CHAP. I. FOOD AND DIGESTION. 43 
 
 within the cells. My son examined soma 
 leaves of the ash and many of the lime, 
 which had fallen off the trees and had been 
 partly dragged into worm-burrows. It is- 
 known that with fallen leaves the starch- 
 grains are preserved in the guard-cells of the 
 stomata. Now in several cases the starch had 
 partially or wholly disappeared from these 
 cells, in the parts which had been moistened 
 by the secretion ; while it was still well pre- 
 served in the other parts of the same leaves* 
 Sometimes the starch was dissolved out of 
 only one of the two guard-cells. The 
 nucleus in one case had disappeared, together 
 with the starch-granules. The mere bury- 
 ing of lime-leaves in damp earth for nine 
 days did not cause the destruction of the 
 starch-granules. On the other hand, the im- 
 mersion of fresh lime and cherry leaves for 
 eighteen hours in artificial pancreatic fluid, 
 led to the dissolution of the starch-granules 
 in the guard-cells as well as in the other 
 cells. 
 
 From the secretion with which the leaves 
 are moistened being alkaline, and from its 
 acting both on the starch-granules and on
 
 44 HABITS OF WORMS. CHAP. I. 
 
 the protoplasmic contents of the cells, we 
 may infer that it resembles in nature not 
 saliva,* but pancreatic secretion ; and we 
 know from Fredericq that a secretion of this 
 kind is found in the intestines of worms. As 
 the leaves which are dragged into the bur- 
 rows are often dry and shrivelled, it is in- 
 dispensable for their disintegration by the 
 unarmed mouths of worms that they should 
 first be moistened and softened ; and fresh 
 leaves, however soft and tender they may be, 
 are similarly treated, probably from habit. 
 The result is that they are partially digested 
 before they are taken into the alimentary 
 canal. I am not aware of any other case of 
 extra-stomachal digestion having been re- 
 corded. The boa-constrictor is said to bathe 
 its prey with saliva, but this is doubtful ; and 
 it is done solely for the sake of lubricating its 
 prey. Perhaps the nearest analogy may be 
 found in such plants as Drosera and Dionaea ; 
 for here animal matter is digested and con- 
 verted into peptone not within a stomach, but 
 on the surfaces of the leaves. 
 
 Claparede doubts whether saliva is secrete*! by worms : see 
 Zeitschrift fur wissenschaft. Zoologie,' B. xix. 1869, p. 601.
 
 CHAP. I. CALCIFEEOUS GLANDS. 45 
 
 Calciferous Glands. These glands (see 
 Fig. 1), judging from their size and from their 
 rich supply of blood-vessels, must be of much 
 importance to the animal. But almost as 
 many theories have been advanced on their 
 use as there have been observers. They 
 consist of three pairs, which in the common 
 earth-worm debouch into the alimentary 
 canal in advance of the gizzard, but pos- 
 teriorly to it in Urochaeta and some other 
 genera,* The two posterior pairs are formed 
 by lamellae, which, according to Claparede, 
 are diverticula from the cesophagus.f These 
 lamellae are coated with a pulpy cellular 
 layer, with the outer cells lying free in in- 
 finite numbers. If one of these glands is 
 punctured and squeezed, a quantity of white 
 pulpy matter exudes, consisting of these free 
 cells. They are minute, and vary in diameter 
 from 2 to 6 /x. They contain in their centres 
 a little excessively fine granular matter ; but 
 they look so like oil globules that Claparede 
 
 * Perrier, ' Archives de Zoolog. exper.' July, 1874, pp. 416, 
 419. 
 
 t ' Zeitschrift fur vrissenschaft. Zoologie,' B. xix. 1869, pp. 
 603-606.
 
 46 HABITS OF WORMS. CHAP. I. 
 
 and others at first treated them with ether. 
 This produces no effect ; but they are quickly 
 dissolved with effervescence in acetic acid, 
 and when oxalate of ammonia is added to 
 the solution a white precipitate is thrown 
 down. We may therefore conclude that 
 they contain carbonate of lime. If the cells 
 are immersed in a very little acid, they 
 become more transparent, look like ghosts, 
 and are soon lost to view ; but if much acid 
 is added, they disappear instantly. After a 
 very large number have been dissolved, a 
 flocculent residue is left, which apparently 
 consists of the delicate ruptured cell-walls. 
 In the two posterior pairs of glands the 
 carbonate of lime contained in the cells oc- 
 casionally aggregates into small rhombic 
 crystals or into concretions, which lie be- 
 tween the lamellae; but I have seen only 
 one case, and Claparede only a very few 
 such cases. 
 
 The two anterior glands differ a little in 
 shape from the four posterior ones, by being 
 more oval. They differ also conspicuously in 
 .generally containing several small, or two or 
 three larger, or a single very large concre-
 
 CHAP. I. CALCIFEKOUS GLANDS. 47 
 
 tion of carbonate of lime, as much as 1^ mm. 
 in diameter. When a gland includes only 
 .a few very small concretions, or, as sometimes 
 happens, none at all, it is easily overlooked. 
 The large concretions are round or oval, and 
 exteriorly almost smooth. One was found 
 which filled up not only the whole gland, as 
 is often the case, but its neck ; so that it 
 resembled an olive-oil flask in shape. These 
 concretions when broken are seen to be 
 more or less crystalline in structure. How 
 they escape from the gland is a marvel ; but 
 that they do escape is certain, for they are 
 often found in the gizzard, intestines, and 
 in the castings of worms, both with those 
 kept in confinement and those in a state of 
 nature. 
 
 Claparede says very little about the 
 structure of the two anterior glands, and he 
 supposes that the calcareous matter of which 
 the concretions are formed is derived from 
 the four posterior glands. But if an anterior 
 gland which contains only small concretions 
 is placed in acetic acid and afterwards 
 dissected, or if sections are made of such 
 a gland without being treated with acid,
 
 48 HABITS OF "WORMS. CHAP. I. 
 
 lamellae like those in the posterior glands 
 and coated with cellular matter could be 
 plainly seen, together with a multitude of 
 free calciferous cells readily soluble in acetic 
 acid. When a gland is completely filled with 
 a single large concretion, there are no free 
 cells, as these have been all consumed in 
 forming the concretion. But if such a con- 
 cretion, or one of only moderately large size, 
 is dissolved in acid, much membranous matter 
 is left, which appears to consist of the remains 
 of the formerly active lamellae. After the 
 formation and expulsion of a large concretion, 
 new lamellae must be developed in some 
 manner. In one section made by my son, the 
 process had apparently commenced, although 
 the gland contained two rather large concre- 
 tions, for near the walls several cylindrical 
 and oval pipes were intersected, which were 
 lined .with cellular matter and were quite 
 filled with free calciferous cells. A great 
 enlargement in one direction of several oval 
 pipes would give rise to the lamellae. 
 
 Besides the free calciferous cells in which 
 no nucleus was visible, other and rather 
 larger free cells were seen on three occasions;
 
 CHAP. I. CALCIFEROUS GLANDS. 49 
 
 and these contained a distinct nucleus and 
 iiucleolus. They were only so far acted on 
 by acetic acid that the nucleus was thus 
 rendered more distinct. A very small con- 
 cretion was removed from between two of the 
 lamella? within an anterior gland. It was 
 imbedded in pulpy cellular matter, with 
 many free calciferous cells, together with a 
 multitude of the larger, free, nucleated cells, 
 and these latter cells were not acted on by 
 acetic acid, while the former were dissolved. 
 From this and other such cases I am led to 
 suspect that the calciferous cells are developed 
 from the larger nucleated ones ; but how 
 this is effected was not ascertained. 
 
 When an anterior gland contains several 
 minute concretions, some of these are generally 
 angular or crystalline in outline, while the 
 greater number are rounded with an irregu- 
 lar mulberry-like surface. Calciferous cells 
 adhered to many parts of these mulberry-like 
 masses, and their gradual disappearance could 
 be traced while they still remained attached. 
 It was thus evident that the concretions are 
 formed from the lime contained within the 
 
 E
 
 50 HABITS OF WORMS. CHAI-. L 
 
 free calciferous cells. As the smaller concre- 
 tions increase in size, they come into contact 
 and unite, thus enclosing the now functionless 
 lamellae and by such steps the formation of 
 the largest concretions could be followed. 
 Why the process regularly takes place in the 
 two anterior glands, and only rarely in the 
 four posterior glands, is quite unknown. 
 Morren says that these glands disappear 
 during the winter ; and I have seen some- 
 instances of this fact, and others in which* 
 either the anterior or posterior glands were 
 at this season so shrunk and empty, that 
 they could be distinguished only with muck 
 difficulty. 
 
 With respect to the function of the calci- 
 ferous glands, it is probable that they pri- 
 marily serve as organs of excretion, and 
 secondarily as an aid to digestion. Worm& 
 consume many fallen leaves ; and it is known 
 that lime goes on accumulating in leaves until 
 they drop off the parent-plant, instead of 
 being re-absorbed into the stem or roots, like 
 various other organic and inorganic sub- 
 stances.* The ashes of a leaf of an acacia 
 
 * DC Tries, ' Landwirth. Jahrbiicher,' 1881, p. 77.
 
 CHAP. I. CALCIFEROUS GLANDS. 51 
 
 have been known to contain as much as 
 72 per cent, of lime. Worms therefore would 
 be liable to become charged with this earth, 
 unless there were some special means for its 
 excretion; and the calciferous glands are 
 well adapted for this purpose. The worms 
 which live in mould close over the chalk, 
 often have their intestines filled with this 
 substance, and their castings are almost white. 
 Here it is evident that the supply of cal- 
 careous matter must be superabundant. 
 Nevertheless with several worms collected on 
 such a site, the calciferous glands contained 
 as many free calciferous cells, and fully as 
 many and large concretions, as did the 
 glands of worms which lived where there was 
 little or no lime ; and this indicates that the 
 lime is an excretion, and not a secretion 
 poured into the alimentary canal for some 
 special purpose. 
 
 On the other hand, the following considera- 
 tions render it highly probable that the 
 carbonate of lime, which is excreted by the 
 glands, aids the digestive process under 
 ordinary circumstances. Leaves during their 
 
 E 2
 
 52 HABITS OF WORMS. CHAP. I. 
 
 decay generate an abundance of various kinds 
 of acids, which have been grouped together 
 under the term of humus acids. We shall 
 have to recur to this subject in our fifth 
 -chapter, and I need here only say that these 
 acids act strongly on carbonate of lime. The 
 half-decayed leaves which are swallowed in 
 .such large quantities by worms would, there- 
 fore, after they have been moistened and 
 triturated in the alimentary canal, be apt to 
 produce such acids. And in the case of 
 .several worms, the contents of the alimentary 
 canal were found to be plainly acid, as shown 
 by litmus paper. This acidity cannot be 
 .attributed to the nature of the digestive fluid, 
 for pancreatic fluid is alkaline ; and we have 
 seen that the secretion which is poured out of 
 the mouths of worms for the sake of pre- 
 paring the leaves for consumption, is likewise 
 alkaline. The acidity can hardly be due to 
 uric acid, as the contents of the upper part of 
 the intestine were often acid. In one case 
 the contents of the gizzard were slightly acid, 
 those of the upper intestines being more 
 plainly acid. In another case the contents of
 
 CHAP. I- CALCIFEROUS GLANDS. 5 
 
 the pharynx were not acid, those of the 
 gizzard doubtfully so, while those of the in- 
 testine were distinctly acid at a distance of 
 5 cm. below the gizzard. Even with the- 
 higher herbivorous and omnivorous animals,, 
 the contents of the large intestine are acid. 
 " This, however, is not caused by any acid 
 ** secretion from the mucous membrane ; the 
 " reaction of the intestinal walls in the larger 
 "as in the small intestine is alkaline. It 
 " must therefore arise from acid fermenta- 
 ** tions going on in the contents them- 
 
 " selves In Carnivora the contents 
 
 " of the coecum are said to be alkaline,, 
 " and naturally the " amount of fermentation 
 "will depend largely on the nature of the 
 "food."* 
 
 With worms not only the contents of the 
 intestines, but their ejected matter or the 
 castings, are generally acid. Thirty castings 
 from different places were tested, and with 
 three or four exceptions were found to be 
 acid ; and the exceptions may have been due 
 
 * M. Foster, 'A Text-Book of Physiology,' 2nd edit. 1878 
 p. 243.
 
 54 HABITS OF WORMS. CHAP. I. 
 
 to such castings not having been recently 
 ejected; for some which were at first acid, 
 were on the following morning, after being 
 dried and again moistened, no longer acid ; 
 and this probably resulted from the humus 
 acids being, as is known to be the case, easily 
 decomposed. Five fresh castings from worms 
 which lived in mould close over the chalk, 
 were of a whitish colour and abounded with 
 calcareous matter; and these were not in 
 the least acid. This shows how effectually 
 carbonate of lime neutralises the intestinal 
 acids. When worms were kept in pots filled 
 with fine ferruginous sand, it was manifest 
 that the oxide of iron, with which the grains 
 of silex were coated, had been dissolved and 
 removed from them in the castings. 
 
 The digestive fluid of worms resembles in 
 its action, as already stated, the pancreatic 
 secretion of the higher animals ; and in these 
 latter, " pancreatic digestion is essentially 
 " alkaline ; the action will not take place 
 "unless some alkali be present; and the 
 " activity of an alkaline juice is arrested by 
 "acidification, and hindered by neutraliza-
 
 CHAP. I. CALCIFEROUS GLANDS. 55 
 
 " tion."* Therefore it seems highly probable 
 that the innumerable calciferous cells, which 
 :are poured from the four posterior glands 
 into the alimentary canal of worms, serve to 
 neutralise more or less completely the acids 
 there generated by the half-decayed leaves. 
 We have seen that these cells are instantly 
 dissolved by a small quantity of acetic acid, 
 and as they do not always suffice to neu- 
 tralise the contents of even the upper part of 
 the alimentary canal, the lime is perhaps 
 aggregated into concretions in the anterior 
 pair of glands, in order that some may be 
 carried down to the posterior parts of the 
 intestine, where these concretions would be 
 rolled about amongst the acid contents. The 
 concretions found in the intestines and in the 
 castings often have a worn appearance, but 
 whether this is due to some amount of 
 attrition or of chemical corrosion could not 
 be told. Claparede believes that they are 
 formed for the sake of acting as mill-stones, 
 and of thus aiding in the trituration of the 
 food. They may give some aid in this way ; 
 
 * M. Foster, ut sup. p. 200.
 
 56 HABITS OF WORMS. CHAP. I. 
 
 but I fully agree with Perrfer that this must 
 be of quite subordinate importance, seeing 
 that the object is already attained by stones 
 being generally present in the gizzards and 
 intestines of worms.
 
 CHAPTER II. 
 HABITS OF WORMS continued. 
 
 Manner in which worms seize objects Their power of suction 
 The instinct of plugging up the mouths of their burrows 
 Stones piled over the burrows The advantages thus gained 
 Intelligence shown by worms in their manner of plugging up 
 their burrows Various kinds of leaves and other objects thus 
 used Triangles of paper Summary of reasons for believing 
 that worms exhibit some intelligence Means by which they 
 excavate their burrows, by pushing away the earth and swal- 
 lowing it Earth also swallowed for the nutritious matter 
 which it contains Depth to which worms burrow, and the 
 construction of their burrows Burrows lined with castings, 
 and in the upper part with leaves The lowest part paved with 
 little stones or seeds Manner iu which the castings arc 
 ejected The collapse of old burrows Distribution of worms 
 Tower-like castings in Bengal Gigantic castings on the 
 Nilgiri Mountains Castings ejected in all countries. 
 
 Ix the pots in which worms were kept, 
 leaves were pinned down to the soil, and 
 at night the manner in which they were 
 seized could be observed. The worms always 
 endeavoured to drag the leaves towards their 
 burrows; and they tore or sucked off small 
 fragments, whenever the leaves were stiffi-
 
 58 HABITS OF WORMS. CHAP. II. 
 
 ciently tender. They generally seized the 
 thin edge of a leaf with their mouths, between 
 the projecting upper and lower lip ; the 
 thick and strong pharynx being at the same 
 time, as Perrier remarks, pushed forward 
 within their bodies, so as to afford a point 
 of resistance for the upper lip. In the case 
 of broad flat objects they acted in a wholly 
 different manner. The pointed anterior 
 extremity of the body, after being brought 
 into contact with an object of this kind, was 
 drawn within the adjoining rings, so that it 
 appeared truncated and became as thick as 
 the rest of the body. This part could then 
 be seen to swell a little ; and this, I believe, 
 is due to the pharynx being pushed a little 
 forwards. Then by a slight withdrawal of 
 the pharynx or by its expansion, a vacuum 
 was produced beneath the truncated slimy 
 end of the body whilst in contact with the 
 object; and by this means the two adhered 
 firmly together.* That under these circum- 
 stances a vacuum was produced was plainly 
 
 * Claparfede remarks (' Zeitschrift fur wissenschaft. Zoolog.' 
 B. 19, 18G9, p. 602) that the pharynx appears from its structure 
 to be adapted for suction.
 
 CHAP. II. THEIR MANNER OF PREHENSION. 59 
 
 seen on one occasion, when a large worm 
 lying beneath a flaccid cabbage leaf tried to 
 drag it away ; for the surface of the leaf 
 directly over the end of the worm's body 
 became deeply pitted. On another occasion 
 a worm suddenly lost its hold on a flat leaf; 
 and the anterior end of the body was momen- 
 tarily seen to be cup-formed. Worms can 
 attach themselves to an object beneath water 
 in the same manner; and I saw one thus 
 dragging away a submerged slice of an 
 onion-bulb. 
 
 The edges of fresh or nearly fresh leaves 
 affixed to the ground were often nibbled by 
 the worms ; and sometimes the epidermis and 
 all the parenchyma on one side was gnawed 
 completely away over a considerable space ; 
 the epidermis alone on the opposite side 
 being left quite clean. The veins were 
 never touched, and leaves were thus some- 
 times partly converted into skeletons. As 
 worms have no teeth and as their mouths 
 consist of very soft tissue, it may be pre- 
 sumed that they consume by means of suction 
 the edges and the parenchyma of fresh 
 leaves, after they have been softened by the
 
 60 HABITS OF WORMS. CHAP. IL 
 
 digestive fluid. They cannot attack such 
 strong leaves as those of sea-kale or large 
 and thick leaves of ivy ; though one of the 
 latter after it had become rotten was reduced 
 in parts to the state of a skeleton. 
 
 Worms seize leaves and other objects, not 
 only to serve as food, but for plugging up 
 the mouths of their burrows ; and this is 
 one of their strongest instincts. They some- 
 times work so energetically that Mr. D. F. 
 Simpson, who has a small walled garden 
 where worms abound in Bayswater, informs 
 me that on a calm damp evening he there 
 heard so extraordinary a rustling noise from 
 under a tree from which many leaves had 
 fallen, that he went out with a light and dis- 
 covered that the noise was caused by many 
 worms dragging the dry leaves and squeezing 
 them into the burrows. Not only leaves, but 
 petioles of many kinds, some flower-pedun- 
 cles, often decayed twigs of trees, bits of 
 paper, feathers, tufts of wool and horse-hairs 
 are dragged into their burrows for this pur- 
 pose. I have seen as many as seventeen 
 petioles of a Clematis projecting from the 
 mouth of one burrow, and ten from the
 
 CHAP. II. PROTECTION OF THEIR BURROWS. 61 
 
 mouth of another. Some of these objects, 
 such as the petioles just named, feathers, &c., 
 are never gnawed by worms. In a gravel- 
 walk in my garden I found many hundred 
 leaves of a pine-tree (P. austriaca or nigri- 
 ^ans) drawn by their bases into burrows. 
 The surfaces by which these leaves are articu- 
 lated to the branches are shaped in as pecu- 
 liar a manner as is the joint between the leg- 
 bones of a quadruped ; and if these surfaces 
 had been in the least gnawed, the fact would 
 have been immediately visible, but there was 
 no trace of gnawing. Of ordinary dicotyle- 
 donous leaves, all those which are dragged 
 into burrows are not gnawed. I have seen 
 as many as nine leaves of the lime-tree 
 drawn into the same burrow, and not nearly 
 all of them had been gnawed ; but such 
 leaves may serve as a store for future con- 
 sumption. Where fallen leaves are abun- 
 dant, many more are sometimes collected 
 over the mouth of a burrow than can be 
 used, so that a small pile of unused leaves is 
 left like a roof over those which have been 
 partly dragged in. 
 
 A leaf in being dragged a little way into
 
 62 HABITS OF WORMS. CHAP. IL 
 
 a cylindrical burrow is necessarily much 
 folded or crumpled. When another leaf is. 
 drawn in, this is done exteriorly to the first 
 one, and so on with the succeeding leaves ; and 
 finally all become closely folded and pressed 
 together. Sometimes the worm enlarges the 
 mouth of its burrow, or makes a fresh one 
 close by, so as to draw in a still larger number 
 of leaves. They often or generally fill up the 
 interstices between the drawn-in leaves with 
 moist viscid earth ejected from their bodies; 
 and thus the mouths of the burrows are 
 securely plugged. Hundreds of such plugged 
 burrows may be seen in many places,, 
 especially during the autumnal and early 
 winter months. But, as will hereafter be 
 shown, leaves are dragged into the burrows- 
 not only for plugging them up and for food, 
 but for the sake of lining the upper part or 
 mouth. 
 
 When worms cannot obtain leaves, petioles, 
 sticks, &c., with which to plug up the mouths: 
 of their burrows, they often protect them by 
 little heaps of stones; and such heaps of 
 smooth rounded pebbles may frequently be 
 seen on gravel-walks. Here there can be no
 
 CHAP. II. PROTECTION OF THEIR BURROWS. 63 
 
 question about food. A lady, who was in- 
 terested in the habits of worms, removed the 
 little heaps of stones from the mouths of 
 several burrows and cleared the surface of the 
 ground for some inches all round. She went 
 out on the following night with a lantern, 
 and saw the worms with their tails fixed in 
 their burrows, dragging the stones inwards 
 by the aid of their mouths, no doubt by 
 suction. "After two nights some of the- 
 " holes had 8 or 9 small stones over 
 " them ; after four nights one had about 
 " 30, and another 34 stones."* One stone 
 which had been dragged over the gravel-walk 
 to the mouth of a burrow weighed two- 
 ounces; and this proves how strong worms 
 are. But they show greater strength in some- 
 times displacing stones in a well-trodden 
 gravel-walk ; that they do so, may be inferred 
 from the cavities left by the displaced stones 
 being exactly filled by those lying over the 
 mouths of adjoining burrows, as I have my- 
 self observed. 
 
 Work of this kind is usually performed 
 
 * An account of her observations is given in the ' Gardeners 1 
 Chronicle,' March 28th, 1868, p. 324.
 
 61 HABITS OF WORMS. CHAP. II. 
 
 during the night ; but I have occasionally 
 known objects to be drawn into the burrows 
 during the day. What advantage the worms 
 derive from plugging up the mouths of their 
 burrows with leaves, &c., or from piling 
 stones over them, is doubtful. They do not 
 act in this manner at the times when they 
 eject much earth from their burrows ; for their 
 castings then serve to cover the mouths. 
 When gardeners wish to kill worms on a 
 lawn, it is necessary first to brush or rake 
 away the castings from the surface, in order 
 that the lime-water may enter the burrows.* 
 It might be inferred from this fact that the 
 mouths are plugged up with leaves, &c., to 
 prevent the entrance of water during heavy 
 rain ; but it may be urged against this view 
 that a few, loose, well-rounded stones are ill- 
 adapted to keep out water. I have moreover 
 seen many burrows in the perpendicularly 
 cut turf-edgings to gravel-walks, into which 
 water could hardly flow, as well plugged as 
 burrows on a level surface. It is not probable 
 that the plugs or piles of stones serve to 
 conceal the burrows from scolopendras, which, 
 
 * London's ' Card. Mag.' xvii. p. 210, as quoted in the ' Cata- 
 logue of the British Museum Wonts,' 1865, p. 327.
 
 CHAP. H. PROTECTION OF THEIE BURROWS. 65 
 
 according to Hoffmeister, * are the bitterest 
 enemies of worms, or from the larger species 
 of Carabus and Staphylinus which attack them 
 ferociously, for these animals are nocturnal, 
 and the burrows are opened at night. May 
 not worms when the mouth of the burrow is 
 protected be able to remain with safety with 
 their heads close to it, which we know that they 
 like to do, but which costs so many of them 
 their lives ? Or may not the plugs check the 
 free ingress of the lowest stratum of air, when 
 chilled by radiation at night, from the sur- 
 rounding ground and herbage ? I am inclined 
 to believe in this latter view : firstly, because 
 when worms were kept in pots in a room with 
 a fire, in which case cold air could not enter the 
 burrows, they plugged them up in a slovenly 
 manner ; and secondarily, because they often 
 coat the upper part of their burrows with 
 leaves, apparently to prevent their bodies from 
 coming into close contact with the cold damp 
 earth. Mr. E. Parfitt has suggested to me 
 that the mouths of the burrows are closed in 
 order that the air within them may be kept 
 thoroughly damp, and this seems the most 
 probable explanation of the habit. But the 
 
 * ' Familie der Regenwurmer,' p. 19. 
 
 F
 
 66 HABITS OF WOEMS. CHAP. II. 
 
 plugging-up process may serve for all the 
 above purposes. 
 
 Whatever the motive may be, it appears 
 that worms much dislike leaving the mouths 
 of their burrows open. Nevertheless they 
 will reopen them at night, whether or not 
 they can afterwards close them. Numerous 
 open burrows may be seen on recently-dug 
 ground, for in this case the worms eject their 
 castings in cavities left in the ground, or in 
 the old burrows instead of piling them over 
 the mouths of their burrows, and they cannot 
 collect objects on the surface by which the 
 mouths might be protected. So again on a 
 recently disinterred pavement of a Roman 
 villa at Abinger (hereafter to be described) 
 the worms pertinaciously opened their bur- 
 rows almost every night, when these had 
 been closed by being trampled on, although 
 they were rarely able to find a few minute 
 stones wherewith to protect them. 
 
 Intelligence shown by worms in their manner 
 of plugging up their burrows. If a man had to 
 plug up a small cylindrical hole, with such 
 objects as leaves, petioles or twigs, he would 
 drag or push them in by their pointed ends ;
 
 CHAP. II. THEIR INTELLIGENCE. 67 
 
 but if these objects were very thin relatively 
 to the size of the hole, he would probably 
 insert some by their thicker or broader ends. 
 The guide in his case would be intelligence. 
 It seemed therefore worth while to observe 
 carefully how worms dragged leaves into 
 their burrows; whether by their tips or 
 bases or middle parts. It seemed more espe- 
 cially desirable to do this in the case of plants 
 not natives to our country ; for although the 
 habit of dragging leaves into their burrows 
 is undoubtedly instinctive with worms, yet 
 instinct could not tell them how to act in 
 the case of leaves about which their pro- 
 genitors knew nothing. If, moreover, worms 
 acted solely through instinct or an unvary- 
 ing inherited impulse, they would draw all 
 kinds of leaves into their burrows in the 
 same manner. If they have no such definite 
 instinct, we might expect that chance would 
 determine whether the tip, base or middle was 
 seized. If both these alternatives are ex- 
 cluded, intelligence alone is left ; unless the 
 worm in each case first tries many different 
 methods, and follows that alone which 
 proves possible or the most easy ; but to act 
 
 G
 
 68 HABITS OF WORMS. CHAP. II. 
 
 in this manner and to try different methods 
 makes a near approach to intelligence. 
 
 In the first place 227 withered leaves of 
 various kinds, mostly of English plants, were 
 pulled out of worm-burrows in several places. 
 Of these, 181 had been drawn into the 
 burrows by or near their tips, so that the 
 foot-stalk projected nearly upright from the 
 mouth of the burrow ; 20 had been drawn in 
 by their bases, and in this case the tips pro- 
 jected from the burrows ; and 26 had been 
 seized near the middle, so that these had 
 been drawn in transversely and were much 
 crumpled. Therefore 80 per cent, (always 
 using the nearest whole number) had been 
 drawn in by the tip, 9 per cent, by the base 
 or foot-stalk, and 1 1 per cent, transversely or 
 by the middle. This alone is almost suffi- 
 cient to show that chance does not determine 
 the manner in which leaves are dragged into 
 the burrows. 
 
 Of the above 227 leaves, 70 consisted of 
 the fallen leaves of the common lime-tree, 
 which is almost certainly not a native of 
 England. These leaves are much acumin- 
 ated towards the tip, and are very broad at
 
 CHAP. II. THEIE INTELLIGENCE. 69 
 
 the base with a well-developed foot-stalk. 
 They are thin and quite flexible when half- 
 withered. Of the 70, 79 per cent, had been 
 drawn in by or near the tip; 4 per cent, 
 by or near the base ; and 17 per cent, trans- 
 versely or by the middle. These proportions 
 agree very closely, as far as the tip is con- 
 cerned, with those before given. But the per- 
 centage drawn in by the base is smaller, which 
 may be attributed to the breadth of the basal 
 part of the blade. We here, also, see that the 
 presence of a foot-stalk, which it might have 
 been expected would have tempted the worms 
 as a convenient handle, has little or no in- 
 fluence in determining the manner in which 
 lime leaves are dragged into the burrows. 
 The considerable proportion, viz., 17 per 
 cent., drawn in more or less transversely 
 depends no doubt on the flexibility of these 
 half-decayed leaves. The fact of so many 
 having been drawn in by the middle, and of 
 some few having been drawn in by the base, 
 renders it improbable that the worms first 
 tried to draw in most of the leaves by one or 
 both of these methods, and that they after- 
 wards drew in 79 per cent, by their tips ; 
 
 G 2
 
 70 HABITS OF WORMS. CHAP. II. 
 
 for it is clear that they would not have failed 
 in drawing them in by the base or middle. 
 
 The leaves of a foreign plant were next 
 searched for, the blades of which were not 
 more pointed towards the apex than towards 
 the base. This proved to be the case with 
 those of a laburnum (a hybrid between 
 Cytisus alpinus and laburnum) for on doubling 
 the terminal over the basal half, they gene- 
 rally fitted exactly ; and when there was 
 any difference, the basal half was a little the 
 narrower. It might, therefore, have been 
 expected that an almost equal number of 
 these leaves would have been drawn in by the 
 tip and base, or a slight excess in favour of 
 the latter. But of 73 leaves (not included in 
 the first lot of 227) pulled out of worm- 
 burrows, 63 per cent, had been drawn in by 
 the tip ; 27 per cent, by the base, and 10 per 
 cent, transversely. We here see that a far 
 larger proportion, viz., 27 per cent, were 
 drawn in by the base than in the case of 
 lime leaves, the blades of which are very 
 broad at the base, and of which only 4 per 
 cent, had thus been drawn in. We may 
 perhaps account for the fact of a still larger
 
 CHAP. II. THEIR INTELLIGENCE. 71 
 
 proportion of the laburnum leaves not hav- 
 ing been drawn in by the base, by worms 
 having acquired the habit of generally drawing 
 in leaves by their tips and thus avoiding the 
 foot-stalk. For the basal margin of the blade 
 in many kinds of leaves forms a large angle 
 with the foot-stalk ; and if such a leaf were 
 drawn in by the foot-stalk, the basal margin 
 would come abruptly into contact with the 
 ground on each side of the burrow, and would 
 render the drawing in of the leaf very difficult. 
 Nevertheless worms break through their 
 habit of avoiding the foot-stalk, if this part 
 offers them the most convenient means for 
 drawing leaves into their burrows. The leaves 
 of the endless hybridised varieties of the 
 Rhododendron vary much in shape ; some are 
 narrowest towards the base and others to- 
 wards the apex. After they have fallen off, 
 the blade on each side of the midrib often 
 becomes curled up while drying, sometimes 
 along the whole length, sometimes chiefly 
 at the base, sometimes towards the apex. 
 Out of 28 fallen leaves on one bed of peat in 
 my garden, no less than 23 were narrower in 
 the basal quarter than in the terminal quarter 
 of their length; and this narrowness was
 
 72 HABITS OF WOEMS. OHAP. U. 
 
 chiefly due to the curling in of the margins. 
 Out of 36 fallen leaves on another bed, in 
 which different varieties of the Rhododendron 
 grew, only 17 were narrower towards the 
 hase than towards the apex. My son William, 
 who first called my attention to this case, 
 picked up 237 fallen leaves in his garden 
 (where the Rhododendron grows in the 
 natural soil) and of these 65 per cent, could 
 have been drawn by worms into their bur- 
 rows more easily by the base or foot-stalk 
 than by the tip ; and this was partly due to 
 the shape of the leaf and in a less degree 
 to the curling in of the margins: 27 per 
 cent, could have been drawn in more easily 
 by the tip than by the base : and 8 per cent. 
 with about equal ease by either end. The 
 shape of a fallen leaf ought to be judged 
 of before one end has been drawn into a 
 burrow, for after this has happened, the free 
 end, whether it be the base or apex, will dry 
 more quickly than the end embedded in the 
 damp ground ; and the exposed margins of 
 the free end will consequently tend to become 
 more curled inwards than they were when 
 the leaf was first seized by the worm. My 
 son found 91 leaves which had been dragged
 
 CHAP. II. THEIR INTELLIGENCE. 73 
 
 by worms into their burrows, though not to a 
 great depth ; of these 66 per cent, had been 
 drawn in by the base or foot-stalk ; and 34 
 per cent, by the tip. In this case, therefore, 
 the worms judged with a considerable degree 
 of correctness how best to draw the withered 
 leaves of this foreign plant into their burrows ; 
 notwithstanding that they had to depart from 
 their usual habit of avoiding the foot-stalk. 
 
 On the gravel-walks in my garden a very 
 large number of leaves of three species of 
 Pinus (P. austriaca, nigricans and sylvestris) 
 are regularly drawn into the mouths of worm- 
 burrows. These leaves consist of two so-called 
 needles, which are of considerable length in the 
 two first and short in the last named species, 
 and are united to a common base ; and it is by 
 this part that they are almost invariably drawn 
 into the burrows. I have seen only two or 
 at most three exceptions to this rule with 
 worms in a state of nature. As the sharply 
 pointed needles diverge a little, and as several 
 leaves are drawn into the same burrow, each 
 tuft forms a perfect chevaux de /rise. On two- 
 occasions many of these tufts were pulled up 
 in the evening, but by the following morning 
 fresh leaves had been pulled in, and the
 
 74 HABITS OF WORMS. CHAP. II. 
 
 burrows were again well protected. These 
 leaves could not be dragged into the burrows 
 to any depth, except by their bases, as a 
 worm cannot seize hold of the two needles at 
 the same time, and if one alone were seized 
 by the apex, the other would be pressed 
 against the ground and would resist the 
 entry of the seized one. This was manifest 
 in the above mentioned two or three excep- 
 tional cases. In order, therefore, that worms 
 should do their work well, they must drag 
 pine-leaves into their burrows by their bases, 
 where the two needles are conjoined. But 
 how they are guided in this work is a per- 
 plexing question. 
 
 This difficulty led my son Francis and my- 
 self to observe worms in confinement during 
 several nights by the aid of a dim light, while 
 they dragged the leaves of the above named 
 pines into their burrows. They moved the 
 anterior extremities of their bodies about the 
 leaves, and on several occasions when they 
 touched the sharp end of a needle they with- 
 drew suddenly as if pricked. But I doubt 
 whether they were hurt, for they are indif- 
 ferent to very sharp objects, and will swallow 
 even rose-thorns and small splinters of glass.
 
 CHAP. II. THEIK INTELLIGENCE. 75 
 
 It may also be doubted, whether the sharp 
 ends of the needles serve to tell them that 
 this is the wrong end to seize ; for the points 
 were cut off many leaves for a length of 
 about one inch, and fifty-seven of them thus 
 treated were drawn into the burrows by 
 their bases, and not one by the cut-off ends. 
 The worms in confinement often seized the 
 needles near the middle and drew them to- 
 wards the mouths of their burrows ; and one 
 worm tried in a senseless manner to drag 
 them into the burrow by bending them. 
 They sometimes collected many more leaves 
 over the mouths of their burrows (as in the 
 case formerly mentioned of lime-leaves) than 
 could enter them. On other occasions, how- 
 ever, they behaved very differently; for as 
 soon as they touched the base of a pine-leaf, 
 this was seized, being sometimes completely en- 
 gulfed in their mouths, or a point very near 
 the base was seized, and the leaf was then 
 quickly dragged or rather jerked into their 
 burrows. It appeared both to my son and 
 myself as if the worms instantly perceived 
 as soon as they had seized a leaf in the proper 
 manner. Nine such cases were observed, 
 but in one of them the worm failed to drag
 
 76 HABITS OF WORMS. CHAP. II. 
 
 the leaf into its burrow, as it was entangled 
 by other leaves lying near. In another case 
 a leaf stood nearly upright with the points of 
 the needles partly inserted into a burrow, but 
 how placed there was not seen ; and then the 
 worm reared itself up and seized the base,, 
 which was dragged into the mouth of the 
 burrow by bowing the whole leaf. On the 
 other hand, after a worm had seized the base 
 of a leaf, this was on two occasions relin- 
 quished from some unknown motive. 
 
 As already remarked, the habit of plugging 
 up the mouths of the burrows with various 
 objects, is no doubt instinctive in worms ; 
 and a very young one, born in one of my 
 pots, dragged for some little distance a Scotch- 
 fir leaf, one needle of which was as long and 
 almost as thick as its own body. No species 
 of pine is endemic in this part of England, 
 it is therefore incredible that the proper 
 manner of dragging pine-leaves into the 
 burrows can be instinctive with our worms. 
 But as the worms on which the above obser- 
 vations were made, were dug up beneath or 
 near some pines, which had been planted 
 there about forty years, it was desirable to 
 prove that their actions were not instinctive.
 
 CHAP. II. THEIK INTELLIGENCE. 77 
 
 Accordingly, pine-leaves were scattered on 
 the ground in places far removed from any 
 pine-tree, and 90 of them were drawn into 
 the burrows by their bases. Only two were 
 drawn in by the tips of the needles, and these 
 were not real exceptions, as one was drawn 
 in for a very short distance, and the two 
 needles of the other cohered. Other pine- 
 leaves were given to worms kept in pots in a 
 warm room, and here the result was different ; 
 for out of 42 leaves drawn into the burrows, 
 no less than 16 were drawn in by the tips 
 of the needles. These worms, however, 
 worked in a careless or slovenly manner ; 
 for the leaves were often drawn in to only 
 a small depth ; sometimes they were merely 
 heaped over the mouths of the burrows, and 
 sometimes none were drawn in. I believe 
 that this carelessness may be accounted for 
 either by the warmth of the air, or by its 
 dampness, as the pots were covered by glass 
 plates ; the worms consequently did not care 
 about plugging up their holes effectually. Pots 
 tenanted by worms and covered with a net 
 which allowed the free entrance of air, were 
 left out of doors for several nights, and now 72 
 leaves were all properly drawn in by their bases.
 
 78 HABITS OF WORMS. CHAP. IL 
 
 It might perhaps be inferred from the facts 
 as yet given, that worms somehow gain a 
 general notion of the shape or structure of 
 pine-leaves, and perceive that it is necessary 
 for them to seize the base where the two 
 needles are conjoined. But the following 
 cases make this more than doubtful. The 
 tips of a large number of needles of P. austriaca 
 were cemented together with shell-lac dis- 
 solved in alcohol, and were kept for some 
 days, until, as I believe, all odour or taste had 
 been lost; and they were then scattered on 
 the ground where no pine-trees grew, near 
 burrows from which the plugging had been 
 removed. Such leaves could have been drawn 
 into the burrows with equal ease by either 
 end ; and judging from analogy and more 
 especially from the case presently to be given 
 of the petioles of Clematis montana, I expected 
 that the apex would have been preferred. 
 But the result was that out of 121 leaves with 
 the tips cemented, which were drawn into bur- 
 rows, 108 were drawn in by their bases, and 
 only 13 by their tips. Thinking that the 
 worms might possibly perceive and dislike the 
 smell or taste of the shell-lac, though this 
 was very improbable, especially after the
 
 CHAP. II. THEIR INTELLIGENCE. 79 
 
 leaves had been left out during several nights, 
 the tips of the needles of many leaves were 
 tied together with fine thread. Of leaves 
 thus treated 150 were drawn into burrows 
 123 by the base and 27 by the tied tips; so 
 that between four and five times as many were 
 drawn in by the base as by the tip. It is 
 possible that the short cut-off ends of the 
 thread with which they were tied, may have 
 tempted the worms to drag in a larger propor- 
 tional number by the tips than when cement 
 was used. Of the leaves with tied and 
 cemented tips taken together (271 in number) 
 85 per cent, were drawn in by the base and 
 15 per cent, by the tips. We may therefore 
 infer that it is not the divergence of the two 
 needles which leads worms in a state of nature 
 almost invariably to drag pine-leaves into 
 their burrows by the base. Nor can it be the 
 sharpness of the points of the needles which 
 determines them ; for, as we have seen, many 
 leaves with the points cut off were drawn in 
 by their bases. "We are thus led to conclude, 
 that with pine-leaves there must be something 
 attractive to worms in the base, notwithstand- 
 ing that few ordinary leaves are drawn in by 
 the base or foot-stalk.
 
 80 HABITS OF WOKMS. CHAP. II. 
 
 Petioles. We will now turn to the petioles 
 or foot-stalks of compound leaves, after the 
 leaflets have fallen off. Those from Clematis 
 montana, which grew over a verandah, were 
 dragged early in January in large numbers 
 into the burrows on an adjoining gravel- 
 walk, lawn, and flower-bed. These petioles 
 vary from 2J to 4j inches in length, are 
 rigid and of nearly uniform thickness, except 
 close to the base where they thicken rather 
 abruptly, being here about twice as thick as 
 in any other part. The apex is somewhat 
 pointed, but soon withers and is then easily 
 broken off. Of these petioles, 314 were pulled 
 out of burrows in the above specified sites; 
 and it was found that 76 per cent, had been 
 drawn in by their tips, and 24 per cent, by 
 their bases ; so that those drawn in by the 
 tip were a little more than thrice as many 
 as those drawn in by the base. Some of those 
 extracted from the well-beaten gravel-walk 
 were kept separate from the others; and of 
 these (59 in number) nearly five times as 
 many had been drawn in by the tip as by 
 the base; whereas of those extracted from 
 the lawn and flower-bed, where from the 
 soil yielding more easily, less care would be
 
 CHAP. II. THEIR INTELLIGENCE. 81 
 
 necessary in plugging up the burrows, the 
 proportion of those drawn in by the tip (130) 
 to those drawn in by the base (48) was 
 rather less than three to one. That these 
 petioles had been dragged into the burrows 
 for plugging them up, and not for food, 
 was manifest, as neither end, as far as I 
 could see, had been gnawed. As several 
 petioles are used to plug up the same burrow, 
 in one case as many as 10, and in another 
 case as many as 15, the worms may perhaps 
 at first draw in a few by the thicker end so 
 as to save labour; but afterwards a large 
 majority are drawn in by the pointed end, in 
 order to plug up the hole securely. 
 
 The fallen petioles of our native ash-tree 
 were next observed, and the rule with most 
 objects, viz., that a large majority are dragged 
 into the burrows by the more pointed end, had 
 not here been followed; and this fact much 
 surprised me at first. These petioles vary in 
 length from 5 to 8^ inches ; they are thick 
 and fleshy towards the base, whence they 
 taper gently towards the apex, which is a little 
 enlarged and truncated where the terminal 
 leaflet had been originally attached. Under 
 some ash-trees growing in a grass-field, 229
 
 82 HABITS OP WORMS. CHAP. II. 
 
 petioles were pulled out of worm burrows 
 early in January, and of these 5T5 per cent, 
 had been drawn in by the ba.se, and 48 '5 per 
 cent, by the apex. This anomaly was how- 
 ever readily explained as soon as the thick 
 basal part was examined ; for in 78 out of 103 
 petioles, this part had been gnawed by worms, 
 just above the horse-shoe shaped articulation. 
 In most cases there could be no mistake about 
 the gnawing ; for ungnawed petioles which 
 were examined after being exposed to the 
 weather for eight additional weeks had not 
 become more disintegrated or decayed near 
 the base than elsewhere. It is thus evident 
 that the thick basal end of the petiole is 
 drawn in not solely for the sake of plugging 
 up the mouths of the burrows, but as food. 
 Even the narrow truncated tips of some 
 few petioles had been gnawed ; and this 
 was the case in 6 out of 37 which were 
 examined for this purpose. Worms, after 
 having drawn in and gnawed the basal end, 
 often push the petioles out of their burrows ; 
 and then drag in fresh ones, either by 
 the base for food, or by the apex for plug- 
 ging up the mouth more effectually. Thus, 
 out of 37 petioles inserted by their tips,
 
 CHAP. II. THEIK INTELLIGENCE. 83 
 
 5 had been previously drawn in by tne- 
 base, for this part had been gnawed. Again,. 
 I collected a handful of petioles lying loose 
 on the ground close to some plugged-up bur- 
 rows, where the surface was thickly strewed 
 with other petioles which apparently had 
 never been touched by worms; and 14 out 
 of 47 (i.e. nearly one-third), after having 
 had their bases gnawed had been pushed 
 out of the burrows and were now lying on 
 the ground. From these several facts we may 
 conclude that worms draw in some petioles 
 of the ash by the base to serve as food, and 
 others by the tip to plug up the mouths of 
 their burrows in the most efficient manner. 
 
 The petioles of Robinia pseudo-acacia vary 
 from 4 or 5 to nearly 12 inches in length; 
 they are thick close to the base before the 
 softer parts have rotted off, and taper much 
 towards the upper end. They are so flexible 
 that I have seen some few doubled up and 
 thus drawn into the burrows of worms. Un- 
 fortunately these petioles were not examined 
 until February, by which time the softer parts 
 had completely rotted off, so that it was im- 
 possible to ascertain whether worms had 
 
 H
 
 84 HABITS OF WORMS. CHAP. IL 
 
 gnawed the bases, though this is in itself 
 probable. Out of 121 petioles extracted from 
 burrows early in February, 68 were imbedded 
 by the base, and 53 by the apex. On 
 February 5 all the petioles which had been 
 drawn into the burrows beneath a Robinia, 
 were pulled up ; and after an interval of 
 eleven days, 35 petioles had been again 
 dragged in, 19 by the base, and 16 by the 
 apex. Taking these two lots together, 56 
 per cent, were drawn in by the base, and 44 
 per cent, by the apex. As all the softer parts 
 had long ago rotted off, we may feel sure, 
 especially in the latter case, that none had 
 been drawn in as food. At this season, there- 
 fore, worms drag these petioles into their 
 burrows indifferently by either end, a slight 
 preference being given to the base. This 
 latter fact may be accounted for by the diffi- 
 culty of plugging up a burrow with objects so 
 extremely thin as are the upper ends. In 
 support of this view, it may be stated that out 
 of the 16 petioles which had been drawn 
 in by their upper ends, the more attenuated 
 terminal portion of 7 had been previously 
 broken off by some accident.
 
 CHAP. H. THEIR INTELLIGENCE. 85 
 
 Triangles of paper. Elongated triangles 
 were cut out of moderately stiff writing-paper, 
 which was rubbed with raw fat on both sides,, 
 so as to prevent their becoming excessively 
 limp when exposed at night to rain and dew. 
 The sides of all the triangles were three 
 inches in length, with the bases of 120 one 
 inch, and of the other 183 half an inch in 
 length. These latter triangles were very 
 narrow or much acuminated.* As a check 
 on the observations presently to be given,, 
 similar triangles in a damp state were seized 
 by a very narrow pair of pincers at different 
 points and at all inclinations with reference 
 to the margins, and were then drawn into 
 a short tube of the diameter of a worm- 
 burrow. If seized by the apex, the triangle 
 was drawn straight into the tube, with its 
 margins infolded; if seized at some little 
 distance from the apex, for instance at half 
 an inch, this much was doubled back within 
 the tube. So it was with the base and basal 
 angles, though in this case the triangles 
 offered, as might have been expected, much 
 
 *' In these narrow triangles the apical angle is 9 34', and the 
 "basal angles 85 13'. In the broader triangles the apical angle is 
 19 Itf and the basal angles 80 25'. 
 
 H 2
 
 86 HABITS OF WORMS. CHAP. IL 
 
 more resistance to being drawn in. If seized 
 near the middle the triangle was doubled up, 
 with the apex and base left sticking out of the 
 tube. As the sides of the triangles were 
 three inches in length, the result of their 
 being drawn into a tube or into a burrow in 
 different ways, may be conveniently divided 
 into three groups : those drawn in by the 
 apex or within an inch of it ; those drawn in 
 by the base or within an inch of it ; and those 
 drawn in by any point in the middle inch. 
 
 In order to see how the triangles would be 
 seized by worms, some in a damp state were 
 given to worms kept in confinement. They 
 were seized in three different manners in the 
 case of both the narrow and broad triangles : 
 viz., by the margin ; by one of the three 
 angles, which was often completely engulfed 
 in their mouths ; and lastly, by suction applied 
 to any part of the flat surface. If lines 
 parallel to the base and an inch apart, are 
 drawn across a triangle with the sides three 
 inches in length, it will be divided into three 
 parts of equal length. Now if worms seized 
 indifferently by chance any part, they 
 would assuredly seize on the basal part or
 
 CHAP. II. THEIR INTELLIGENCE. 87 
 
 division far oftener than on either of the two 
 other divisions. For the area of the basal to 
 the apical part is as 5 to 1, so that the 
 chance of the former being drawn into a 
 burrow by suction, will be as 5 to 1, compared 
 with the apical part. The base offers two 
 angles and the apex only one, so that the 
 former would have twice as good a chance 
 (independently of the size of the angles) of 
 being engulfed in a worm's mouth, as would 
 the apex. It should, however, be stated that 
 the apical angle is not often seized by worms ; 
 the margin at a little distance on either side 
 being preferred. I judge of this from having 
 found in 40 out of 46 cases in which tri- 
 angles had been drawn into burrows by their 
 apical ends, that the tip had been doubled 
 back within the burrow for a length of 
 between Joth of an inch and 1 inch. Lastly, 
 the proportion between the margins of the basal 
 and apical parts is as 3 to 2 for the broad, 
 and 2 1 to 2 for the narrow triangles. From 
 these several considerations it might certainly 
 have been expected, supposing that worms 
 seized hold of the triangles by chance, that a 
 considerably larger proportion would have
 
 88 HABITS OF WORMS. CHAP. II. 
 
 been dragged into the burrows by the basal 
 than by the apical part; but we shall im- 
 mediately see how different was the result. 
 
 Triangles of the above specified sizes were 
 scattered on the ground in many places and 
 on many successive nights near worm-bur- 
 rows, from which the leaves, petioles, twigs, 
 &c., with which they had been plugged, were 
 removed. Altogether 303 triangles were 
 drawn by worms into their burrows : 12 others 
 were drawn in by both ends, but as it was im- 
 possible to judge by which end they had been 
 first seized, these are excluded. Of the 303, 
 62 per cent, had been drawn in by the apex 
 (using this term for all drawn in by the 
 apical part, one inch in length) ; 15 per cent, 
 by the middle ; and 23 per cent, by the basal 
 part. If they had been drawn indifferently 
 by any point, the proportion for the apical, 
 middle and basal parts would have been 3 3' 3 
 per cent, for each ; but, as we have just seen, 
 it might have been expected that a much 
 larger proportion would have been drawn in 
 by the basal than by any other part. As the 
 case stands, nearly three times as many were 
 drawn in by the apex as by the base. If we
 
 CHAP. II. THEIK INTELLIGENCE. 89 
 
 consider the broad triangles by themselves, 
 59 per cent, were drawn in by the apex, 25 
 per cent, by the middle, and 16 per cent, by 
 the base. Of the narrow triangles, 65 per 
 cent, were drawn in by the apex, 14 per cent, 
 by the middle, and 21 per cent, by the base ; 
 so that here those drawn in by the apex were 
 more than 3 times as many as those drawn 
 in by the base. We may therefore conclude 
 that the manner in which the triangles are 
 drawn into the burrows is not a matter of 
 chance. 
 
 In eight cases, two triangles had been drawn 
 into the same burrow, and in seven of these 
 cases, one had been drawn in by the apex and 
 the other by the base. This again indicates 
 that the result is not determined by chance. 
 Worms appear sometimes to revolve in the 
 act of drawing in the triangles, for five out of 
 the whole lot had been wound into an irregular 
 spire round the inside of the burrow. Worms 
 kept in a warm room drew 63 triangles 
 into their burrows ; but, as in the case of the 
 pine-leaves, they worked in a rather careless 
 manner, for only 44 per cent, were drawn in 
 by the apex, 22 per cent, by the middle, and
 
 90 HABITS OF WORMS. CHAP. II. 
 
 33 per cent, by the base. In five cases, two 
 triangles were drawn into the same burrow. 
 
 It may be suggested with much apparent 
 probability that so large a proportion of the 
 triangles were drawn in by the apex, not from 
 the worms having selected this end as the 
 most convenient for the purpose, but from 
 having first tried in other ways and failed. 
 This notion was countenanced by the manner 
 in which worms in confinement were seen to 
 drag about and drop the triangles ; but then 
 they were working carelessly. I did not at 
 first perceive the importance of this subject, 
 but merely noticed that the bases of those tri- 
 angles which had been drawn in by the apex, 
 were generally clean and not crumpled. The 
 subject was afterwards attended to carefully. 
 In the first place several triangles which had 
 been drawn in by the basal angles, or by the 
 base, or a little above the base, and which 
 were thus much crumpled and dirtied, were 
 left for some hours in water and were then 
 well shaken while immersed ; but neither 
 the dirt nor the creases were thus removed. 
 Only slight creases could be obliterated, 
 even by pulling the wet triangles several
 
 CHAP. II. THEIE INTELLIGENCE. 91 
 
 times through my fingers. Owing to the 
 slime from the worms' bodies, the -dirt was 
 not easily washed off. We may therefore 
 conclude that if a triangle, before being 
 dragged in by the apex, had been dragged 
 into a burrow by its base with even a slight 
 degree of force, the basal part would long 
 retain its creases and remain dirty. The con- 
 dition of 89 triangles (65 narrow and 24 
 broad ones), which had been drawn in by the 
 apex, was observed ; and the bases of only 7 
 of them were at all creased, being at the same 
 time generally dirty. Of the 82 uncreased 
 triangles, 14 were dirty at the base ; but it 
 does not follow from this fact that these had 
 first been dragged towards the burrows by 
 their bases ; for the worms sometimes covered 
 large portions of the triangles with slime, 
 and these when dragged by the apex over the 
 ground would be dirtied ; and during rainy 
 weather, the triangles were often dirtied over 
 one whole side or over both sides. If the 
 worms had dragged the triangles to the 
 mouths of their burrows by their bases, as often 
 as by their apices, and had then perceived, 
 without actually trying to draw them into the 

 
 92 
 
 HABITS OF WORMS. 
 
 CHAP. II. 
 
 burrow, that the broader end was not well 
 adapted for this purpose even in this case 
 a large proportion would probably have had 
 their basal ends dirtied. We may therefore 
 infer improbable as is the inference that 
 worms are able by some means to judge 
 which is the best end by which to draw 
 triangles of paper into their burrows. 
 
 The percentage results of the foregoing ob- 
 servations on the manner in which worms 
 draw various kinds of objects into the mouths 
 of their burrows may be abridged as follows : 
 
 
 Drawn 
 
 
 
 
 into the 
 
 Drawn 
 
 Drawn 
 
 Nature of Object. 
 
 burrows, 
 by or 
 
 in, by or 
 near the 
 
 in, by or 
 near the 
 
 
 near the 
 
 middle. 
 
 base. 
 
 
 apex. 
 
 
 
 Leaves of various kinds . . : 
 
 80 
 
 11 
 
 9 
 
 of the Lime, basal margin of 
 
 
 
 
 "blade broad, apex acumi- 
 
 
 
 
 nated . . . . 
 
 79 
 
 17 
 
 4 
 
 of a Laburnum, basal part of 
 
 
 
 
 blade as narrow as, or some- 
 
 
 
 
 times little narrower than 
 
 
 
 
 the apical part. 
 
 63 
 
 10 
 
 27 
 
 of the Rhododendron, basal 
 
 
 
 
 part of blade often narrower 
 than the apical part . 
 
 34 
 
 ,, 
 
 GG 
 
 *f ~D: i 1 **e A. 
 
 
 
 
 needles arising from a com- 
 
 mon base 
 
 
 
 100
 
 CHAP. II. 
 
 THEIR INTELLIGENCE. 
 
 93 
 
 
 Drawn 
 
 
 
 
 into the 
 
 Drawn 
 
 Drawn 
 
 Nature of Object. 
 
 burrows, 
 by or 
 
 in, by or 
 near the 
 
 in, by or 
 Bear the 
 
 
 near the 
 
 middle. 
 
 base. 
 
 
 apex. 
 
 
 
 Petioles of a Clematis, somewhat 
 
 
 
 
 pointed at the apex, and 
 blunt at the base 
 
 76 
 
 
 24 
 
 of the Ash, the thick basal 
 
 
 
 
 end often drawn in to serve 
 
 
 
 
 as food .... 
 
 48-5 
 
 
 51'5 
 
 ' of Eobinia, extremely thin, 
 
 
 
 
 especially towards the apex, 
 
 
 
 
 so as to be ill-fitted for 
 
 
 
 
 plugging up the burrows . 
 
 44 
 
 
 56 
 
 Triangles of paper, of the two sizes . 
 
 62 
 
 15 
 
 23 
 
 s^F 4-"U 11 svns* 1 
 
 59 
 
 25 
 
 16 
 
 
 65 
 
 14 
 
 21 
 
 
 If we consider these several cases, we can 
 hardly escape from the conclusion that worms 
 show some degree of intelligence in their 
 manner of plugging up their burrows. Each 
 particular object is seized in too uniform a 
 manner, and from causes which we can 
 generally understand, for the result to be 
 attributed to mere chance. That every object 
 has not been drawn in by its pointed end, 
 may be accounted for by labour having been 
 saved through some being inserted by their 
 broader or thicker ends. No doubt worms
 
 94: HABITS OP WORMS. CHAP. IL 
 
 are led by instinct to plug up their burrows ; 
 and it might have been expected that they 
 would have been led by instinct how best 
 to act in each particular case, independently 
 of intelligence. We see how difficult it is to 
 judge whether intelligence comes into play, 
 for even plants might sometimes be thought 
 to be thus directed; for instance when dis- 
 placed leaves re-direct their upper surfaces 
 towards the light by extremely complicated 
 movements and by the shortest course. With 
 animals, actions appearing due to intelligence 
 may be performed through inherited habit 
 without any intelligence, although aborigin- 
 ally thus acquired. Or the habit may have 
 been acquired through the preservation and 
 inheritance of beneficial variations of some 
 other habit ; and in this case the new habit 
 will have been acquired independently of 
 intelligence throughout the whole course 
 of its development. There is no a priori 
 improbability in worms having acquired 
 special instincts through either of these two 
 latter means. Nevertheless it is incredible 
 that instincts should have been developed 
 in reference to objects, such as the leaves of
 
 CHAP. II. THEIR INTELLIGENCE. 95 
 
 petioles of foreign plants, wholly unknown 
 to the progenitors of the worms which act 
 in the described manner. Nor are their actions 
 so unvarying or inevitable as are most true 
 instincts. 
 
 As worms are not guided by special in- 
 stincts in each particular case, though pos- 
 sessing a general instinct to plug up their 
 burrows, and as chance is excluded, the next 
 most probable conclusion seems to be that 
 they try in many different ways to draw in 
 objects, and at last succeed in some one way. 
 But it is surprising that an animal so low 
 in the scale as a worm should have the 
 capacity for acting in this manner, as many 
 higher animals have no such capacity. For 
 instance, ants may be seen vainly trying 
 to drag an object transversely to their 
 course, which could be easily drawn longi- 
 tudinally; though after a time they gener- 
 ally act in a wiser manner. M. Fabre 
 states* that a Sphex an insect belong- 
 ing to the same highly-endowed order 
 with ants stocks its nest with paralysed 
 
 * See his interesting work, ' Souvenirs entomologiques,' 1879 
 pp. 168-177.
 
 96 HABITS OF WORMS. CHAP. II. 
 
 grasshoppers, which are invariably dragged 
 into the burrow by their antennae. When 
 these were cut off close to the head, the 
 Sphex seized the palpi ; but when these 
 were likewise cut off, the attempt to drag 
 its prey into the burrow was given up in 
 despair. The Sphex had not intelligence 
 enough to seize one of the six legs or 
 the ovipositor of the grasshopper, which, as 
 M. Fabre remarks, would have served equally 
 well. So again, if the paralysed prey with 
 an egg attached to it be taken out of the 
 cell, the Sphex after entering and finding the 
 cell empty, nevertheless closes it up in the 
 usual elaborate manner. Bees will try to 
 escape and go on buzzing for hours on a 
 window, one half of which has been left open. 
 Even a pike continued during three months 
 to dash and bruise itself against the glass 
 sides of an aquarium, in the vain attempt to 
 seize minnows on the opposite side.* A cobra- 
 snake was seen by Mr. Layard f to act much 
 more wisely than either the pike or the Sphex ; 
 
 * Mobius, ' Die Bewegungen der Thiere,' &c., 1873, p. 111. 
 t ' Annals and Mag. of N. History,' series ii. voL ix. 1852 
 p. 333.
 
 HAP. II. THEIR INTELLIGENCE. 97 
 
 it had swallowed a toad lying within a hole, 
 and could not withdraw its head ; the toad 
 was disgorged, and began to crawl away ; it 
 was again swallowed and again disgorged; 
 and now the snake had learnt by experience, 
 for it seized the toad by one of its legs and 
 drew it out of the hole. The instincts of 
 even the higher animals are often followed 
 in a senseless or purposeless manner : the 
 weaver-bird will perseveringly wind threads 
 through the bars of its cage, as if building a 
 nest : a squirrel will pat nuts on a wooden 
 floor, as if he had just buried them in the 
 ground : a beaver will cut up logs of wood and 
 drag them about, though there is no water to 
 dam up ; and so in many other cases. 
 
 Mr. Romanes, who has specially studied 
 the minds of animals, believes that we can 
 safely infer intelligence, only when we see an 
 individual profiting by its own experience. 
 By this test the cobra showed some intelli- 
 gence ; but this would have been much 
 plainer if on a second occasion he had drawn 
 a toad out of a hole by its leg. The Sphex 
 failed signally in this respect. Now if 
 worms try to drag objects into their burrows
 
 98 HABITS OF WORMS. CHAP. II. 
 
 first in one way and then in another, until 
 they at last succeed, they profit, at least in 
 each particular instance, by experience. 
 
 But evidence has been advanced showing 
 that worms do not habitually try to draw 
 objects into their burrows in many different 
 ways. Thus half-decayed lime-leaves from 
 their flexibility could have been drawn in by 
 their middle or basal parts, and were thus 
 drawn into the burrows in considerable 
 numbers; yet a large majority were drawn 
 in by or near the apex. The petioles of the 
 Clematis could certainly have been drawn in 
 with equal ease by the base and apex ; yet 
 threetimes and in certain cases five times as 
 many were drawn in by the apex as by the 
 base. It might have been thought that the 
 loot-stalks of leaves would have tempted the 
 worms as a convenient handle ; yet they are- 
 not largely used, except when the base of the 
 blade is narrower than the apex. A large 
 number of the petioles of the ash are drawn 
 in by the base ; but this part serves the 
 worms as food. In the case of pine-leaves 
 worms plainly show that they at least do 
 not seize the leaf by chance ; but their
 
 CHAP. II. THEIR INTELLIGENCE. 99 
 
 choice does not appear to be determined by 
 the divergence of the two needles, and the 
 consequent advantage or necessity of drawing 
 them into their burrows by the base. With 
 respect to the triangles of paper, those which 
 had been drawn in by the apex rarely had 
 their bases creased or dirty ; and this shows 
 that the worms had not often first tried to 
 drag them in by this end. 
 
 If worms are able to judge, either before 
 drawing or after having drawn an object 
 close to the mouths of their burrows, how 
 best to drag it in, they must acquire some 
 notion of its general shape. This they pro- 
 bably acquire by touching it in many places 
 with the anterior extremity of their bodies, 
 which serves as a tactile organ. It may be 
 well to remember how perfect the sense of 
 touch becomes in a man when born blind and 
 deaf, as are worms. If worms have the 
 power of acquiring some notion, however 
 rude, of the shape of an object and of their 
 burrows, as seems to be the case, they deserve 
 to be called intelligent ; for they then act in 
 nearly the same manner as would a man 
 under similar circumstances.
 
 .100 HABITS OP WORMS. CHAP. II. 
 
 To sum up, as chance does not determine 
 the manner in which objects are drawn into 
 the burrows, and as the existence of special- 
 ized instincts for each particular case cannot 
 be admitted, the first and most natural sup- 
 position is that worms try all methods until 
 they at last succeed ; but many appearances 
 are opposed to such a supposition. One 
 alternative alone is left, namely, that worms, 
 although standing low in the scale of organiz- 
 ation, possess some degree of intelligence. 
 This will strike every one as very impro- 
 bable ; but it may be doubted whether we 
 know enough about the nervous system of 
 the lower animals to justify our natural dis- 
 trust of such a conclusion. With respect to 
 the small size of the cerebral ganglia, we 
 should remember what a mass of inherited 
 knowledge, with some power of adapting 
 means to an end, is crowded into the minute 
 brain of a worker-ant. 
 
 Means by which icorms excavate their 
 burrows. This is effected in two ways ; by 
 pushing away the earth on all sides, and by 
 swallowing it. In the former case, the worm 
 inserts the stretched out and attenuated
 
 CHAP. II. EXCAVATION OF THEIR BURROWS. 101 
 
 anterior extremity of its body into any little 
 crevice, or hole; and then, as Perrier re- 
 marks,* the pharynx is pushed forwards into 
 this part, which consequently swells and 
 pushes away the earth on all sides. The 
 anterior extremity thus serves as a wedge. 
 It also serves, as we have before seen, for 
 prehension and suction, and as a tactile organ. 
 A worm was placed on loose mould, and it 
 buried itself in between two and three 
 minutes. On another occasion four worms 
 disappeared in 1 5 minutes between the sides 
 of the pot and the earth, which had been 
 moderately pressed down. On a third oc- 
 casion three large worms and a small one 
 were placed on loose mould well mixed with 
 fine sand and firmly pressed down, and they 
 all disappeared, except the tail of one, in 
 3.5 minutes. On a fourth occasion six large 
 worms were placed on argillaceous mud 
 mixed with sand firmly pressed down, and 
 they disappeared, except the extreme tips of 
 the tails of two of them, in 40 minutes. In 
 none of these cases, did the worms swallow, 
 as far as could be seen, any earth. They 
 
 * ' Archives de Zoolog. exper.' torn. iii. 1874, p. 405. 
 
 l 2
 
 102 HABITS OF WORMS. CHAP. II 
 
 generally entered the ground close to the 
 sides of the pot 
 
 A pot was next filled with very fine ferru- 
 ginous sand, which was pressed down, well 
 watered, and thus rendered extremely com- 
 pact. A large worm left on the surface did 
 not succeed in penetrating it for some hours, 
 and did not bury itself completely until 25 
 hrs. 40 min. had elapsed. This was effected 
 by the sand being swallowed, as was evident 
 by the large quantity ejected from the vent y 
 long before the whole body had disappeared. 
 Castings of a similar nature continued to lie 
 ejected from the burrow during the whole 
 of the following day 
 
 As doubts have been expressed by some 
 writers whether worms ever swallow earth 
 solely for the sake of making their burrows, 
 some additional cases may be given. A mass 
 of fine reddish sand, 23 inches in thickness, 
 left on the ground for nearly two years, 
 had been penetrated in many places by 
 worms ; and their castings consisted partly of 
 the reddish sand and partly of black earth 
 brought up from beneath the mass. This 
 sand had been dug up from a considerable
 
 CHAP. II. EXCAVATION OF THEIR BURROWS. 103 
 
 depth, and was 01 so poor a nature that 
 weeds could not grow on it. It is therefore 
 highly improbable that it should have been 
 swallowed by the worms as food. Again in 
 u field near my house the castings frequently 
 consist of almost pure chalk, which lies at only 
 a, little depth beneath the surface ; and here 
 again it is very improbable that the chalk 
 should have been swallowed for the sake of 
 the very little organic matter which could 
 have percolated into it from the poor over- 
 lying pasture. Lastly, a casting thrown up 
 through the concrete and decayed mortar 
 between the tiles, with which the now ruined 
 aisle of Beaulieu Abbey had formerly been 
 paved, was washed, so that the coarser 
 matter alone was left. This consisted of 
 grains of quartz, micaceous slate, other rocks, 
 and bricks or tiles, many of them from -^ to 
 T\J- inch in diameter. No one will suppose 
 that these grains were swallowed as food, yet 
 they formed more than half of the casting, 
 for they weighed 19 grains, the whole cast- 
 ing having weighed 33 grains. Whenever a 
 worm burrows to a depth of some feet in 
 undisturbed compact ground, it must form its
 
 104 HABITS OF WORMS. CHAP. II.. 
 
 passage by swallowing the earth ; for it is 
 incredible that the ground could yield on all 
 sides to the pressure of the pharynx when 
 pushed forwards within the worm's body. 
 
 That worms swallow a larger quantity of 
 earth for the sake of extracting any nutritious 
 matter which it may contain than for making 
 their burrows, appears to me certain. But 
 as this old belief has been doubted by so high 
 an authority as Claparede, evidence in its 
 favour must be given in some detail. There 
 is no a priori improbability in such a belief, 
 for besides other annelids, especially the 
 Arenicola marina, which throws up such a 
 profusion of castings on our tidal sands, and 
 which it is believed thus subsists, there are 
 animals belonging to the most distinct classes, 
 which do not burrow, but habitually swallow 
 large quantities of sand ; namely, the mollus- 
 can Onchidium and many Echinoderms.* 
 
 If earth were swallowed only when worms 
 deepened their burrows or made new ones, 
 castings would be thrown up only occasion- 
 ally ; but in many places fresh castings may 
 
 * I state this on the authority of Semper, "Reisen iiu 
 Archipel der Philippinen," Th. ii. 1877. p. 30. 

 
 CIIAP. II. EARTH SWALLOWED AS FOOD. 105 
 
 be seen every morning, and the amount of 
 earth ejected from the same burrow on succes- 
 sive days is large. Yet worms do not burrow 
 to a great depth, except when the weather 
 is very dry or intensely cold. On my lawn 
 the black vegetable mould or humus is only 
 about 5 inches in thickness, and overlies light- 
 coloured or reddish clayey soil: now when 
 castings are thrown up in the greatest 
 profusion, only a small proportion are light 
 coloured, and it is incredible that the worms 
 should daily make fresh burrows in every 
 direction in the thin superficial layer of 
 dark -coloured mould, unless they obtained 
 nutriment of some kind from it. I have ob- 
 served a strictly analogous case in a field near 
 my house where bright red clay lay close 
 beneath the surface. Again on one part of 
 the Downs near Winchester the vegetable 
 mould overlying the chalk was found to be 
 only from 3 to 4 inches in thickness ; and the 
 many castings here ejected were as black as 
 ink and did not effervesce with acids ; so that 
 the worms must have confined themselves to 
 this thin superficial layer of mould, of which 
 large quantities were daily swallowed. In
 
 106 HABITS OF WORMS. CHAP. II. 
 
 another place at no great distance the cast- 
 ings were white ; and why the worms should 
 have burrowed into the chalk in some places 
 and not in others, I am unable to conjecture. 
 
 Two great piles of leaves had been left to 
 decay in my grounds, and months after their 
 removal, the bare surface, several yards in 
 diameter, was so thickly covered during 
 several months with castings that they formed 
 an almost continuous layer; and the large 
 number of worms which lived here must have 
 subsisted during these months on nutritious 
 matter contained in the black earth. 
 
 The lowest layer from another pile of de- 
 cayed leaves mixed with some earth was ex- 
 amined under a high power, and the number 
 of spores of various shapes arid sizes which 
 it contained was astonishingly great; and 
 these crushed in the gizzards of worms may 
 largely aid in supporting them. When- 
 ever castings are thrown up in the greatest 
 number, few or no leaves are drawn into the 
 burrows ; for instance the turf along a hedge- 
 row, about 200 yards in length, was daily 
 observed in the autumn during several weeks, 
 and every morning many fresh castings were
 
 CHAP. II EAETH SWALLOWED AS FOOD. 107 
 
 seen ; but not a single leaf was drawn into these 
 burrows. These castings from their blackness 
 and from the nature of the subsoil could not 
 have been brought up from a greater depth 
 than 6 or 8 inches. On what could these 
 worms have subsisted during this whole time, 
 if not on matter contained in the black earth ? 
 On the other hand, whenever a large number 
 of leaves are drawn into the burrows, the 
 worms seem to subsist chiefly on them, for 
 few earth-castings are then ejected on the 
 surface. This difference in the behaviour of 
 worms at different times, perhaps explains a 
 statement by Claparede, namely, that triturated 
 leaves and earth are always found in distinct 
 parts of their intestines. 
 
 Worms sometimes abound in places where 
 they can rarely or never obtain dead or 
 living leaves ; for instance, beneath the pave- 
 ment in well-swept courtyards, into which 
 leaves are only occasionally blown. My son 
 Horace examined a house, one corner of 
 which had subsided; and he found here in 
 the cellar, which was extremely damp, many 
 small worm-castings thrown up between the 
 stones with which the cellar was paved ; and
 
 108 HABITS OF WORMS. CHAP. 1L 
 
 in this case it is improbable that the worms 
 could ever have obtained leaves. Mr. A. C. 
 Horner confirms this account, as he has seen 
 castings in the cellars of his house, which is 
 an old one, at Tonbridge. 
 
 But the best evidence, known to me, of 
 worms subsisting for at least considerable 
 periods of time solely on the organic matter 
 contained in earth, is afforded by some facts 
 communicated to me by Dr. King. Near 
 Nice large castings abound in extraordinary 
 numbers, so that 5 or were often found 
 within the space of a square foot. They 
 consist of fine, pale-coloured earth, containing 
 calcareous matter, which after having passed 
 through the bodies of worms and being dried, 
 coheres with considerable force. I have 
 reason to believe that these castings had been 
 formed by species of Perichseta, which have 
 been naturalised here from the East.* They 
 
 * Dr. King gave me some worms collected near Nice, which,, 
 as he "believes, had constructed these castings. They were sent 
 to M. Perrier, who with great kindness examined and named them 
 for me : they consisted of Perichceta affinis, a native of Cochin 
 China and of the Philippines ; P. Luzonica, a native of Luzon 
 in the Philippines ; and P. JJoulleti, which lives near Calcutta. 
 M. Perrier informs me that species of Perichajta have heen natural- 
 ised in the gardens near Montpellier and in Algiers. Before I
 
 CHAP. II. EARTH SWALLOV.'ED AS FOOD. 
 
 109 
 
 rise like towers (see Fig. 2), with their sum- 
 mits often a little broader than their bases,, 
 
 Fig. 2. 
 
 Tower-like casting from near Nice, constructed ot earth, voided 
 probably by a species of Perichjeta : of natural size, copied from 
 a photograph. 
 
 retimes to a height of above 3 and often 
 
 had any reason to suspect that the tower-like castings from Nice 
 had been formed by worms not endemic in the country, I was 
 greatly surprised to see how closely they resembled castings sent 
 to me from near Calcutta, where it is known that species of 
 Perichjeta abound.
 
 110 HABITS OF WORMS. CHAP. II. 
 
 to a height of 2^ inches. The tallest of those 
 which were measured was 3*3 inches in height 
 and 1 inch in diameter. A small cylindrical 
 passage runs up the centre of each tower, 
 through which the worm ascends to eject the 
 earth which it has swallowed, and thus to 
 add to its height. A structure of this kind 
 would not allow leaves being easily dragged 
 from the surrounding ground into the bur- 
 rows ; and Dr. King, who looked carefully, 
 never saw even a fragment of a leaf thus 
 drawn in. Nor could any trace be discovered 
 of the worms having crawled down the ex- 
 terior surfaces of the towers in search of 
 leaves; and had they done so, tracks would 
 almost certainly have been left on the upper 
 part whilst it remained soft. It does not, 
 however, follow that these worms do not 
 draw leaves into their burrows during some 
 other season of the year, at which time they 
 would not build up their towers. 
 
 From the several foregoing cases, it can 
 hardly be doubted that worms swallow earth, 
 not only for the sake of making their bur- 
 rows, but for obtaining food. Hensen, how- 
 ever, concludes from his analyses of mould
 
 
 CHAP. II. DEPTH OF THEIR BURROWS. Ill 
 
 that worms probably could not live on. 
 ordinary vegetable mould, though he admits 
 that they might be nourished to some extent 
 by leaf-mould.* But we have seen that 
 worms eagerly devour raw meat, fat, and 
 dead worms ; and ordinary mould can hardly 
 fail to contain many ova, larvae, and small 
 living or dead creatures, spores of crypto- 
 gamic plants, and microcoeci, such as those 
 which give rise to saltpetre. These various 
 organisms, together with some cellulose from 
 any leaves and roots not utterly decayed, 
 might well account for such large quantities 
 of mould being swallowed by worms. It 
 may be worth while here to recall the fact 
 that certain species of Utricularia, which grow 
 in damp places in the tropics, possess bladders 
 beautifully constructed for catching minute 
 subterranean animals ; and these traps would 
 not have been developed unless many small 
 animals inhabited such soil. 
 
 The depth to which worms penetrate, and 
 the construction of their burrows. Although 
 worms usually live near the surface, yet they 
 
 * 'Zeitschrift fur wissenschaft. Zoolog.' B. xxviii. 1877, 
 p. 364.
 
 112 HABITS OF WORMS. CHAP. II. 
 
 burrow to a considerable depth during long- 
 continued dry weather and severe cold. In 
 Scandinavia, according to Eisen, and in Scot- 
 land, according to Mr. Lindsay Carnagie, the 
 burrows run down to a depth of from 7 to 8 
 feet ; in North Germany, according to Hoff- 
 meister, from 6 to 8 feet, but Hensen says, 
 from 3 to 6 feet. This latter observer has seen 
 worms frozen at a depth of 1^ feet beneath 
 the surface. I have not myself had many 
 opportunities for observation, but I have often 
 met with worms at depths of 3 to 4 feet. 
 In a bed of fine sand overlying the chalk, 
 which had never been disturbed, a worm was 
 cut into two at 55 inches, and another was 
 found here at Down in December at the bottom 
 of its burrow, at 61 inches beneath the surface. 
 Lastly, in earth near an old Roman Villa, 
 which had not been disturbed for many centu- 
 ries, a worm was met with at a depth of 66 
 inches ; and this was in the middle of August. 
 The burrows run down perpendicularly, or 
 more commonly a little obliquely. They are 
 said sometimes to branch, but as far as I have 
 seen this does not occur, except in recently 
 dug ground and near the surface. They are
 
 CHAP. II. CONSTRUCTION OF THEIR BURROWS. 113 
 
 generally, or as I believe invariably, lined 
 with a thin layer of fine, dark-coloured earth 
 voided by the worms ; so that they must 
 at first be made a little wider than their 
 ultimate diameter. I have seen several 
 burrows in undisturbed sand thus lined at 
 a depth of 4 ft. 6 in. ; and others close 
 to the surface thus lined in recently dug 
 ground. The walls of fresh burrows are 
 often dotted with little globular pellets of 
 voided earth, still soft and viscid ; and these, 
 as it appears, are spread out on all sides by 
 the worm as it travels up or down its burrow. 
 The lining thus formed becomes very com- 
 pact and smooth when nearly dry, and 
 closely fits the worm's body. The minute 
 reflexed bristles which project in rows on 
 all sides from the body, thus have excellent 
 points of support ; and the burrow is rendered 
 well adapted for the rapid movement of the 
 animal. The lining appears also to strengthen 
 the walls, and perhaps saves the worm's body 
 from being scratched. I think so because 
 several burrows which passed through a layer 
 of sifted coal-cinders, spread over turf to a 
 thickness of 1 J inch, had been thus lined to an
 
 114 HABITS OF WORMS. CHAP. If. 
 
 unusual thickness. In this case tne worms, 
 judging from the castings, had pushed the 
 cinders away on all sides and had not 
 swallowed any of them. In another place, 
 burrows similarly lined, passed through a 
 layer of coarse coal-cinders, 3| inches in 
 thickness. We thus see that the burrows are 
 not mere excavations, but may rather be 
 compared with tunnels lined with cement. 
 
 The mouths of the burrow are in addition 
 often lined with leaves ; and this is an instinct 
 distinct from that of plugging them up, and 
 does not appear to have been hitherto noticed. 
 Many leaves of the Scotch-fir or pine (Pinus 
 sylvestris) were given to worms kept in con- 
 finement in two pots ; and when after several 
 weeks the earth was carefully broken up, the 
 upper parts of three oblique burrows were 
 found surrounded for lengths of 7, 4, and 
 3J inches with pine-leaves, together with 
 fragments of other leaves which had been 
 given the worms as food. Glass beads and 
 bits of tile, which had been strewed on the 
 surface of the soil, were stuck into the inter- 
 stices between the pine-leaves ; and these 
 interstices were likewise plastered with the
 
 CHAP. II. CONSTRUCTION OF THEIR BURROWS. 115 
 
 viscid castings voided by the worms. The 
 structures thus formed cohered so well, that I 
 succeeded in removing one with only a little 
 earth adhering to it. It consisted of a slightly 
 curved cylindrical case, the interior of which 
 could be seen through holes in the sides and 
 at either end. The pine-leaves had all been 
 drawn in by their bases ; and the sharp points 
 of the needles had been pressed into the 
 lining of voided earth. Had this not been 
 effectually done, the sharp points would have 
 prevented the retreat of the worms into their 
 burrows ; and these structures would have 
 resembled traps armed with converging 
 points of wire, rendering the ingress of an 
 .animal easy and its egress difficult or inr 
 possible. The skill shown by these worms 
 is noteworthy and is the more remarkable, as 
 the Scotch pine is not a native of this district. 
 After having examined these burrows 
 made by worms in confinement, I looked at 
 those in a flower-bed near some Scotch pines. 
 These had all been plugged up in the ordinary 
 manner with the leaves of this tree, drawn in 
 for a length of from 1 to 1^ inch; but the 
 mouths of many of them were likewise lined 
 
 K
 
 116 HABITS OF WORMS. CHAP. II. 
 
 with them, mingled with fragments of other 
 kinds of leaves, drawn in to a depth of 4 or 5 
 inches. Worms often remain, as formerly 
 stated, for a long time close to the mouths 
 of their burrows, apparently for warmth ; 
 and the basket-like structures formed of 
 leaves would keep their bodies from corning 
 into close contact with the cold damp earth. 
 That they habitually rested on the pine-leaves, 
 was rendered probable by their clean and 
 almost polished surfaces. 
 
 The burrows which run far down into the 
 ground, generally, or at least often, terminate 
 in a little enlargement or chamber. Here, ac- 
 cording to Hoifmeister, one or several worms 
 pass the winter rolled up into a ball. Mr. 
 Lindsay Carnagie informed me (1838) that 
 he had examined many burrows over a stone- 
 quarry in Scotland, where the overlying 
 boulder-clay and mould had recently been 
 cleared away, and a little vertical cliff thus 
 left. In several cases the same burrow was a 
 little enlarged at two or three points one 
 beneath the other ; and all the burrows ter- 
 minated in a rather large chamber, at a depth 
 of 7 or 8 feet from the surface. These chain-
 
 CHAP. II. CONSTRUCTION OF THEIR BURROWS. 117 
 
 bers contained many small sharp bits of stone 
 and husks of flax-seeds. They must also 
 have contained living seeds, for on the follow- 
 ing spring Mr. Carnagie saw grass-plants 
 sprouting out of some of the intersected 
 chambers. I found at Abinger in Surrey 
 two burrows terminating in similar chambers 
 at a depth of 36 and 41 inches, and these 
 were lined or paved with little pebbles, 
 about as large as mustard seeds ; and in 
 one of the chambers there was a decayed 
 oat-grain, with its husk. Hensen likewise 
 states that the bottoms of the burrows are 
 lined with little stones ; and where these 
 could not be procured, seeds, apparently of 
 the pear, had been used, as many as fifteen 
 having been carried down into a single 
 burrow, one of which had germinated.* We 
 thus see how easily a botanist might be 
 deceived who wished to learn how long 
 deeply buried seeds remained alive, if he 
 were to collect earth from a considerable 
 depth, on the supposition that it could 
 contain only seeds which had long lain 
 buried. It is. probable that the little stones, 
 
 * ' Zeitscbrift fur wissenschaft. Zoolog.' B. xxviii. 1877, p. 356 
 
 K 2
 
 "118 HABITS OF WORMS. CHAP. II. 
 
 .as well as the seeds, are carried down from 
 the surface by being swallowed ; for a sur- 
 prising number of glass beads, bits of tile 
 and of glass were certainly thus carried down 
 'by worms kept in pots ; but some may have 
 been carried down within their mouths. The 
 tsole conjecture which I can form why worms 
 line their winter-quarters with little stones 
 ;and seeds, is to prevent their closely coiled-up 
 foodies from coming into close contact with 
 "the surrounding cold soil ; and such contact 
 would perhaps interfere with their respiration 
 which is effected by the skin alone. 
 
 A worm after swallowing earth, whether 
 for making its burrow or for food, soon comes 
 to the surface to empty its body. The ejected 
 earth is thoroughly mingled with the intestinal 
 secretions, and is thus rendered viscid. After 
 being dried it sets hard. I have watched 
 worms during the act of ejection, and when 
 the earth was in a very liquid state it was 
 ejected in little spurts, and by a slow peri- 
 staltic movement when not so liquid. It is 
 not cast indifferently on any side, but with 
 some care, first on one and then on another 
 side ; the tail being used almost like a trowel.
 
 CHAP. II. EJECTION OF THEIR CASTINGS. 119' 
 
 When a worm comes to the surface to eject 
 earth, the tail protrudes, but when it collects- 
 leaves its head must protrude. Worms there- 
 fore must have the power of turning round! 
 ill their closely-fitting burrows ; and this, as- 
 it appears to us, would be a difficult feat. As 
 soon as a little heap has been formed, the- 
 worm apparently avoids, for the sake of 
 safety, protruding its tail ; and the earthy 
 matter is forced up through the previously 
 deposited soft mass. The mouth of the same- 
 burrow is used for this purpose for a consider- 
 able time. In the case of the tower-like 
 castings (see Fig. 2) near Nice, and of the- 
 similar but still taller towers from Bengal 
 (hereafter to be described and figured), a 
 considerable degree of skill is exhibited in 
 their construction. Dr. King also observed 
 that the passage up these towers hardly ever 
 ran in the same exact line with the under- 
 lying burrow, so that a thin cylindrical object 
 such as a haulm of grass, could not be 
 passed down the tower into the burrow ; and 
 this change of direction probably serves in 
 some manner as a protection. 
 
 Worms do not always eject their castings on
 
 120 HABITS OF WORMS. CHAP. II. 
 
 the surface of the ground. When they can 
 find any cavity, as when burrowing in newly 
 turned-up earth, or between the stems of 
 banked-up plants, they deposit their castings 
 in such places. So again any hollow beneath 
 a large stone lying on the surface of the 
 ground, is soon filled up with their castings. 
 According to Hensen, old burrows are habitu- 
 ally used for this purpose ; but as far as iny 
 experience serves, this is not the case, except- 
 ing with those near the surface in recently dug 
 ground. I think that Hensen may have been 
 deceived by the walls of old burrows, lined 
 with black earth, having sunk in or collapsed ; 
 for black streaks are thus left, and these are 
 conspicuous when passing through light- 
 coloured soil, and might be mistaken for 
 completely filled-up burrows. 
 
 It is certain that old burrows collapse in 
 the course of time ; for as we shall see in the 
 next chapter, the fine earth voided by worms, 
 if spread out uniformly, would form in many 
 places in the course of a year a layer -J- of an 
 inch in thickness; so that at any rate this large 
 amount is not deposited within the old unused 
 burrows. If the burrows did not collapse,
 
 CHAP. II. THE COLLAPSE OF OLD BURROWS. 121 
 
 tlie whole ground would be first thickly 
 riddled with holes to a depth of ahout ten 
 inches, and in fifty years a hollow unsup- 
 ported space, ten inches in depth, would be 
 left. The holes left by the decay of succes- 
 sively formed roots of trees and plants must 
 likewise collapse in the course of time. 
 
 The burrows of worms run down perpen- 
 dicularly or a little obliquely, and where the 
 soil is at all argillaceous, there is no difficulty 
 in believing that the walls would slowly flow 
 or slide inwards during very wet weather. 
 When, however, the soil is sandy or 
 mingled with many small stones, it can 
 hardly be viscous enough to flow .inwards 
 during even the wettest weather; but another 
 agency may here come into play. After 
 much rain the ground swells, and as it cannot 
 expand laterally, the surface rises ; during dry 
 weather it sinks again. For instance, a large 
 flat stone laid on the surface of a field sank 
 3*33 mm. whilst the weather was dry between 
 May 9th and June 13th, and rose 1*91 mm. 
 between September 7th and 19th of the same 
 year, much rain having fallen during the latter 
 part of this time. During frosts and thaws
 
 122 HABITS OF WORMS. CHAP. II. 
 
 the movements were twice as great. These 
 observations were made by my son Horace, 
 who will hereafter publish an account of the 
 movements of this stone during successive 
 wet and dry seasons, and of the effects of its 
 being undermined by worms. Now when 
 the ground swells, if it be penetrated by 
 cylindrical holes, such as worm-burrows, 
 their walls will tend to yield and be pressed 
 inwards ; and the yielding will be greater 
 in the deeper parts (supposing the whole 
 to be equally moistened) from the greater 
 weight of the superincumbent soil which has 
 to be raised, than in the parts near the sur- 
 face. When the ground dries, the walls will 
 shrink a little and the burrows will be a 
 little enlarged. Their enlargement, however, 
 through the lateral contraction of the 
 ground, will not be favoured, but rather op- 
 posed, by the weight of the superincumbent 
 soil. 
 
 Distribution of Worms. Earth-worms are 
 found in all parts of the world, and some of 
 the genera have an enormous range.* They 
 inhabit the most isolated islands ; they 
 
 * Pcrrier, ' Archives de Zoolog. exper.' torn. 3, p. 378, 1874.
 
 CHAP. II THEIR WIDE DISTRIBUTION. 123 
 
 abound in Iceland, and are known to exist 
 in the West Indies, St. Helena, Madagascar, 
 New Caledonia and Tahiti. In the Antarctic 
 regions, worms from Kerguelen Land have 
 been described by Ray Lankester; and I 
 found them in the Falkland Islands. How 
 they reach such isolated islands is at present 
 quite unknown. They are easily killed by 
 salt-water, and it does not appear probable 
 that young worms or their egg-capsules could 
 be carried in earth adhering to the feet or 
 beaks of land-birds. Moreover Kerguelen 
 Land is not now inhabited by any land-bird. 
 
 In this volume we arc chiefly concerned with 
 the earth cast up by worms, and I have gleaned 
 a few facts on this subject with respect to 
 distant lands. Worms throw up plenty of 
 castings in the United States. In Venezuela, 
 castings, probably ejected by species of 
 Urochaeta, are common in the gardens and 
 fields, but not in the forests, as I hear from 
 Dr. Ernst of Caracas. He collected 156 
 castings from the court-yard of his house, 
 having an area of 200 square yards. They 
 varied in bulk from half a cubic centimeter to 
 five cubic centimeters, and were on an average
 
 124. HABITS OF WORMS. CHAP. II. 
 
 three cubic centimeters. They were, therefore, 
 -of small size in comparison with those often 
 found in England ; for six large castings from 
 a field near my house averaged 1 6 cubic centi- 
 meters. Several species of earth-worms are 
 common in St. Catharina in South Brazil, and 
 Fritz Miiller informs me " that in most parts of 
 " the forests and pasture-lands, the whole soil, 
 " to a depth of a quarter of a metre, looks as if it 
 " had passed repeatedly through the intestines 
 " of earth-worms, even where hardly any cast- 
 4i ings are to be seen on the surface." A 
 gigantic but very rare species is found there, 
 the burrows of which are sometimes even two 
 centimeters or nearly % of an inch in diameter, 
 and which apparently penetrate the ground 
 to a great depth. 
 
 In the dry climate of New South Wales, I 
 hardly expected that worms would be com- 
 mon ; but Dr. Gr. Krefft of Sydney, to whom 
 I applied, after making enquiries from 
 gardeners and others, and from his own 
 observations, informs me that their castings 
 abound. He sent me some collected after 
 heavy rain, and they consisted of little pellets, 
 about '15 inch in diameter ; and the blackened
 
 CHAP. II. THEIR WIDE DISTRIBUTION. 125 
 
 :sandy earth of which they were formed still 
 cohered with considerable tenacity. 
 
 The late Mr. John Scott of the Botanic 
 Gardens near Calcutta made many observa- 
 tions for me 011 worms living under the hot 
 ;and humid climate of Bengal. The castings 
 abound almost everywhere, in jungles and in 
 the open ground, to a greater degree, as he 
 thinks, than in England. After the water 
 has subsided from the flooded rice-fields, the 
 whole surface very soon becomes studded with 
 castings a fact which much surprised Mr, 
 :Scott, as he did not know how long worms 
 could survive beneath water. They cause 
 much trouble in the Botanic garden, "for 
 '" some of the finest of our lawns can be kept 
 " in anything like order only by being almost 
 " daily rolled ; if left undisturbed for a few days 
 ** they become studded with large castings." 
 These closely resemble those described as 
 abounding near Nice ; and they are probably 
 the work of a species of Perichasta. They 
 .stand up like towers, with an open passage in 
 the centre. 
 
 A figure of one of these castings from a 
 photograph is here given (Fig. 3). The
 
 126 
 
 HABITS OF WORMS. 
 
 CIIAP. IE. 
 
 largest received by me was 3^ inches in 
 height and 1*35 inch in diameter ; another 
 
 Fig. 3. 
 
 A tower-like casting, probably ejected by a species of Perichasta 
 from the Botanic Garden, Calcutta : of natural size, engraved 
 from a photograph 
 
 was only | inch in diameter and 2| in height.
 
 CHAP. II. THEIR WIDE DISTRIBUTION. 127 
 
 In the following year, Mr. Scott measured 
 several of the largest ; one was inches in 
 height and nearly 1J in diameter : two others 
 were 5 inches in height and respectively 2 
 and rather more than 2J inches in diameter. 
 The average weight of the 22 castings sent to 
 me was 35 grammes (li oz.) ; and one of them 
 weighed 44*8. grammes (or 2 oz.). All these 
 eastings were thrown up either in one night 
 or in two. Where the ground in Bengal is 
 dry, as under large trees, castings of a different 
 kind are found in vast numbers : these con- 
 sist of little oval or conical bodies, from about 
 the gV to rather above -^ of an inch in 
 length. They are obviously voided by a 
 distinct species of worms. 
 
 The period during which worms near 
 Calcutta , display such extraordinary activity 
 lasts for only a little over two months, 
 namely, during the cool season after the rains. 
 At this time they are generally found within 
 about 10 inches beneath the surface. During 
 the hot season they burrow to a greater depth, 
 and are then found coiled up and apparently 
 hybernating. Mr. Scott has never seen them 
 at a greater depth than 2J feet, but has heard
 
 128 HABITS OF WORMS. CHAP. IT. 
 
 of their having been found at 4 feet. Within 
 the forests, fresh castings may he found even 
 during the hot season. The worms in the 
 Botanic garden, during the cool and dry 
 season, draw many leaves and little sticks 
 into the mouths of their burrows, like our 
 English worms; but they rarely act in this 
 manner during the rainy season. 
 
 Mr. Scott saw worm-castings on the lofty 
 mountains of Sikkim in Xorth India. In 
 South India Dr. King found in one 
 place, on the plateau of the Nilgiris, at an 
 elevation of 7000 feet, " a good many 
 castings," which are interesting for their 
 great size. The worms which eject them are- 
 seen only during the wet season, and are- 
 reported to be from 12 to 15 inches in length, 
 and as thick as a man's little finger. These- 
 castings were collected by Dr. King after 
 a period of 110 days without any rain; and 
 they must have been ejected either during 
 the north-east or more probably during 
 the previous south-west monsoon ; for their 
 surfaces had suffered some disintegration and 
 they were penetrated by many fine roots. A 
 drawing is here given (Fig. 4) of one which
 
 CHAP. II. THEIR WIDE DISTRIBUTION. 129" 
 
 seems to have best retained its original size 
 and appearance. Notwithstanding some loss 
 from disintegration, five of the largest of these 
 castings (after having been well sun-dried) 
 weighed each on an average 89-5 grammes,. 
 
 
 Fig. 4. 
 
 A casting from the Nilgiri Mountains in South India ; of 
 natural size, engraved from a photograph. 
 
 or above 3 oz. ; and the largest weighed 
 123-14 grammes, or 4^- oz., that is, above a. 
 quarter of a pound ! The largest convolutions 
 were rather more than one inch in diameter ; 
 but it is probable that they had subsided a little
 
 130 HABITS OF WORMS. CHAP. II. 
 
 whilst soft, and that their diameters had thus 
 been increased. Some had flowed so much 
 that they now consisted of a pile of almost flat 
 confluent cakes. All were formed of fine, 
 rather light-coloured earth, and were surpris- 
 ingly hard and compact, owing no doubt to 
 the animal matter by which the particles of 
 earth had been cemented together. They 
 did not disintegrate, even when left for some 
 hours in water. Although they had been 
 cast up on the surface of gravelly soil, they 
 contained extremely few bits of rock, the 
 largest of which was only '15 inch in 
 diameter. 
 
 Dr. King saw in Ceylon a worm about 2 
 feet in length and ^ inch in diameter ; and 
 he was told that it was a very common species 
 during the wet season. These worms must 
 throw up castings at least as large as those on 
 the Nilgiri Mountains; but Dr. King saw 
 none during his short visit to Ceylon. Suffi- 
 cient facts have now been given, showing 
 that worms do much work in bringing up 
 fine earth to the surface in most or all parts 
 of the world, and under the most different 
 climates.
 
 ( 131 ) 
 
 CHAPTER III. 
 
 THE AMOUNT OF FIXE EARTH BROUGHT UP BY 
 WORMS TO THE SURFACE. 
 
 Rate at which various objects strewed on the surface of grass- 
 fields are covered up by the castings of worms The burial of 
 a paved path The slow subsidence of great stones left on the 
 surface The number of worms which live within a given 
 space The weight of earth ejected from a burrow, and from 
 all the burrows within a given space The thickness of the 
 layer of mould which the castings on a given space would 
 form within a given time if uniformly spread out The slow 
 rate at which mould can increase to a great thickness 
 Conclusion. 
 
 WE now come to the more immediate subject 
 of this volume, namely, the amount of earth 
 which is brought up by worms from beneath 
 the surface, and is afterwards spread out more 
 or less completely by the rain and wind. The 
 amount can be judged of by two methods, - 
 by the rate at which objects left on the 
 surface are buried, and more accurately by 
 weighing the quantity brought up within a 
 
 L
 
 132 AMOUNT OF EAKTH CHAP. III. 
 
 given time. We will begin with the first 
 method, as it was first followed. 
 
 Near Maer Hall in Staffordshire, quick-lime 
 had been spread about the year 1827 thickly 
 over a field of good pasture-land, which had 
 not since been ploughed. Some square holes 
 were dug in this field in the beginning of 
 October 183*7 ; and the sections showed a 
 layer of turf, formed by the matted roots of 
 the grasses, J inch in thickness, beneath 
 which, at a depth of 2J inches (or 3 inches 
 from the surface), a layer of the lime in 
 powder or in small lumps could be distinctly 
 seen running all round the vertical sides of 
 the holes. The soil beneath the layer of 
 lime was either gravelly or of a coarse sandy 
 nature, and differed considerably in appear- 
 ance from the overlying dark-coloured fine 
 mould. Coal-cinders had been spread over 
 a part of this same field either in the year 
 1833 or 1834; and when the above holes 
 were dug, that is after an interval of 3 or 4 
 years, the rinders formed a line of black spots 
 round the holes, at a depth of 1 inch beneath 
 the surface, parallel to and above the white 
 layer of lime. Over another part of this field
 
 CHAP. III. BROUGHT UP BY WORMS. 133 
 
 cinders had been strewed, only about half-a- 
 year before, and these either still lay on the 
 surface or were entangled among the roots of 
 the grasses ; and I here saw the commence- 
 ment of the burying process, for worm-cast- 
 ings had been heaped on several of the 
 smaller fragments. After an interval of 
 4f years this field was re-examined, and now 
 the two layers of lime and cinders were found 
 almost everywhere at a greater depth than 
 before by nearly 1 inch, we will say by f of 
 an inch. Therefore mould to an average 
 thickness of '22 of an inch had been annually 
 brought up by the worms, and had been 
 spread over the surface of this field. 
 
 Coal-cinders had been strewed over another 
 field, at a date which could not be positively 
 ascertained, so thickly that they formed 
 (October, 1837) a layer, 1 inch in thickness 
 at a depth of about 3 inches from the surface. 
 The layer was so continuous that the over- 
 lying dark vegetable mould was connected 
 with the sub-soil of red clay only by the roots 
 of the grasses ; and when these were broken, 
 the mould and the red clay fell apart. In a 
 third field, on which coal-cinders and burnt 
 
 L 2
 
 134 AMOUNT OF EARTH CHAP. III. 
 
 marl had been strewed several times at un- 
 known dates, holes were dug in 1842 ; and a 
 layer of cinders could be traced at a depth 
 of 3j| inches, beneath which at a depth of 
 9J inches from the surface there was a line 
 of cinders together .with burnt marl. On the 
 sides of one hole there were two layers of 
 cinders, at 2 and 3^ inches beneath the sur- 
 face ; and below them at a depth in parts 
 of 9J, and in other parts of 10 J inches there 
 were fragments of burnt marl. In a fourth 
 field two layers of lime, one above the other, 
 could be distinctly traced, and beneath them 
 a layer of cinders and burnt marl at a depth 
 of from 10 to 12 inches below the surface. 
 
 A piece of waste, swampy land was 
 enclosed, drained, ploughed, harrowed and 
 thickly covered in the year 1822 with burnt 
 marl and cinders. It was sowed with grass 
 seeds, and now supports a tolerably good but 
 coarse pasture. Holes were dug in this field 
 in 1837, or 15 years after its reclamation, 
 and we see in the accompanying diagram 
 (Fig. 5), reduced to half of the natural scale, 
 that the turf was ^ inch thick, beneath which 
 there was a layer of vegetable mould 2 J inches
 
 CHAP. III. BEOUQHT UP BY WOKMS. 
 
 135 
 
 thick. This layer did not contain fragments 
 of any kind ; but beneath it there was a layer 
 of mould, 1 J inch in thickness, full of fragments 
 
 Fig. 5. 
 
 Section, reduced to half the natural scale, of the vegetable mould 
 in a field, drained and reclaimed fifteen years previously ; A, 
 turf; B, vegetable mould without any stones; C, mould with 
 fragments of burnt marl, coal-cinders and quartz pebbles; 
 D, sub-soil of black, peaty sand with quartz pebbles. 
 
 of burnt marl, conspicuous fro'm their red 
 colour, one of which near the bottom was an
 
 .136 AMOUNT OF EARTH CHAP. III. 
 
 inch in length ; and other fragments of coal- 
 cinders together with a few white quartz 
 pebbles. Beneath this layer and at a depth of 
 4^ inches from the surface, the original black, 
 peaty, sandy soil with a few quartz pebbles 
 was encountered. Here therefore the frag- 
 ments of burnt marl and cinders had been 
 covered in the course of 15 years by a layer 
 of fine vegetable mould, only 2J inches in 
 thickness, excluding the turf. Six and a half 
 years subsequently this field was re-examined, 
 and the fragments were now found at from 
 4 to 5 inches beneath the surface. So that 
 in this interval of 6 years, about 1^ inch of 
 mould had been added to the superficial layer. 
 I am surprised that a greater quantity had 
 not been brought up during the whole 21 J 
 years, for in the closely underlying black, 
 peaty soil there were many worms. It is, 
 however, probable that formerly, whilst the 
 land remained poor, worms were scanty ; and 
 the mould would then have accumulated 
 slowly. The average annual increase of thick- 
 ness for the whole period is *19 of an inch. 
 
 Two other cases are worth recording. In 
 the spring of 1835, a field, which had
 
 CHAP. IIL BKOUGHT UP BY WOEMS. 137 
 
 long existed as poor pasture and was so 
 swampy that it trembled slightly when 
 stamped on, was thickly covered with red 
 sand so that the whole surface appeared at 
 first bright red. When holes were dug in 
 this field after an interval of about 2 J years, 
 the sand formed a layer at a depth of f in. 
 beneath the surface. In 1842 (i.e., 7 years 
 after the sand had been laid on) fresh holes 
 were dug, and now the red sand formed a 
 distinct layer, 2 inches beneath the surface., 
 or 1|- inch beneath the turf; so that on an 
 average, '21 inch of mould had been annu- 
 ally brought to the surface. Immediately 
 beneath the layer of red sand, the original 
 substratum of black sandy peat extended. 
 
 A grass field, likewise not far from Maer 
 Hall, had formerly been thickly covered with 
 marl, and was then left for several years as 
 pasture; it was afterwards ploughed. A 
 friend had three trenches dug in this field 
 28 years after the application of the marl,* 
 
 * This case is given in a postscript to my paper in the 
 ' Transact. Geolog. Soc.' (Vol. v. p. 505), and contains a serious 
 error, as in the account received I mistook the figure 30 for 80. 
 The tenant, moreover, formerly said that he had marled the field 
 thirty years before, but was now positive that this was done in
 
 138 AMOUNT OF EARTH CHAP. III. 
 
 and a layer of the marl fragments could be 
 traced at a depth, carefully measured, of 12 
 inches in some parts, and of 14 inches in 
 other parts. This difference in depth de- 
 pended on the layer being horizontal, whilst 
 the surface consisted of ridges and furrows 
 from the field having been ploughed. The 
 tenant assured me that it had never been 
 turned up to a greater depth than from 6 to 8 
 inches ; and as the fragments formed an un- 
 broken horizontal layer from 12 to 14 inches 
 beneath the surface, these must have been 
 buried by the worms whilst the land was 
 in pasture before it was ploughed, for other- 
 wise they would have been indiscriminately 
 scattered by the plough throughout the 
 whole thickness of the soil. Four-and-a-half 
 years afterwards I had three holes dug in 
 this field, in which potatoes had been lately 
 planted, and the layer of marl-fragments was 
 now found 13 inches beneath the bottoms of 
 the furrows, and therefore probably 15 inches 
 
 1809, that is twenty-eight years before the first examination of 
 the field by my friend. The error, as far as the figure 80 is 
 concerned, was corrected in an article by me, in the * Gardeners' 
 Chronicle,' 1844, p. 218.
 
 CHAP. III. BROUGHT UP BY WORMS. 139 
 
 beneath the general level of the field. It 
 should, however, be observed that the thick- 
 ness of the blackish sandy soil, which had 
 been thrown up by the worms above the marl- 
 fragments in the course of 32 years, would 
 have measured less than 15 inches, if the field 
 had always remained as pasture, for the soil 
 would in this case have been much more 
 compact. The fragments of marl almost rested 
 on an undisturbed sub-stratum of white sand 
 with quartz pebbles ; and as this would be 
 little attractive to worms, the mould would 
 hereafter be very slowly increased by their 
 action. 
 
 "We will now give some cases of the action 
 of worms, on land differing widely from 
 the dry sandy or the swampy pastures just 
 described. The chalk formation extends all 
 round my house in Kent; and its surface, 
 from having been exposed during an immense 
 period to the dissolving action of rain-water, 
 is extremely irregular, being abruptly fes- 
 tooned and penetrated by many deep well- 
 like cavities.* During the dissolution of the 
 
 * These pits or pipes are still in process of formation. During 
 the last forty years I have seen or heard of five cases, in which a
 
 140 AMOUNT OF EAETH CHAP. III. 
 
 chalk, the insoluble matter, including a vast 
 number of unrolled flints of all sizes, has 
 
 circular space, several feet in diameter, suddenly fell in, leaving 
 on the field an open hole with perpendicular sides, some feet in 
 depth. This occurred in one of my own fields, whilst it was 
 being rolled, and the hinder quarters of the shaft horse fell in ; two 
 or three cart-loads of rubbish were required to fill up the hole. 
 The subsidence occurred where there was a broad depression, as 
 if the surface had fallen in at several former periods. I heard 
 of a hole which must have been suddenly formed at the bottom 
 of a small shallow pool, where sheep had been washed during 
 many years, and into which a man thus occupied fell to his great 
 terror. The rain-water over this whole district sinks perpen- 
 dicularly into the ground, but the chalk is more porous in certain 
 places than in others. Thus the drainage from the overlying 
 clay is directed to certain points, where a greater amount of cal- 
 careous matter is dissolved than elsewhere. Even narrow open 
 channels are sometimes formed in the solid chalk. As the chalk 
 is slowly dissolved over the whole country, but more in some 
 parts than in others, the undissolved residue that is the over- 
 lying mass of red clay with flints, likewise sinks slowly down, 
 and tends to fill up the pipes or cavities. But the upper part 
 of the red clay holds together, aided probably by the roots of 
 plants, for a longer time than the lower parts, and thus forms 
 a roof, which sooner or later falls in, as in the above mentioned 
 five cases. The downward movement of the clay may be com- 
 pared with that of a glacier, but is incomparably slower ; and this 
 movement accounts for a singular fact, namely, that the much 
 elongated flints which are embedded in the chalk in a nearly 
 horizontal position, are commonly found standing nearly or quite 
 upright in the red clay. This fact is so common that the work- 
 men assured me that this was their natural position. I roughly 
 measured one which stood vertically, and it was of the same 
 length and of the same relative thickness as one of my arms. 
 These elongated flints must get placed in their upright position,
 
 CHAP. III. BROUGHT UP BY WORMS. 141 
 
 been left on the surface and forms a bed oi 
 stiff red clay, full of flints, and generally 
 from 6 to 14 feet in thickness. Over the red 
 clay, wherever the land has long remained as 
 pasture, there is a layer a few inches in 
 thickness, of dark-coloured vegetable mould. 
 
 A quantity of broken chalk was spread, 
 on December 20, 1842, over a part of a field 
 near my house, which had existed as pasture 
 certainly for 30, probably for twice or thrice 
 as many years. The chalk was laid on the 
 land for the sake of observing at some future 
 period to what depth it would become buried. 
 At the end of November, 1871, that is after an 
 interval of 29 years, a trench was dug across 
 this part of the field; and a line of white nodules 
 could be traced on both sides of the trench, at 
 a depth of 7 inches from the surface. The 
 mould, therefore, (excluding the turf) had 
 
 on the same principle that a trunk of a tree left on a glacier 
 assumes a position parallel to the line of motion. The flints 
 iu the clay which form almost half its bulk, are very often 
 broken, though not rolled or abraded ; and this may be ac- 
 counted for by their mutual pressure, whilst the whole mass is 
 subsiding. I may add that the chalk here appears to have been 
 originally covered in parts by a thin bed of fine sand with some 
 perfectly rounded flint pebbles, probably of Tertiary age ; for such 
 sand often partly fills up the deeper pits or cavities iu the chalk.
 
 H2 AMOUNT OF EARTH CHAP. III. 
 
 here been thrown tip at an average rate of 
 *22 inch per year. Beneath the line of 
 chalk nodules there was in parts hardly any 
 fine earth free of flints, while in other parts 
 there was a layer, 2 inches in thickness. In 
 this latter case the mould was altogether 9i 
 inches thick ; and in one such spot a nodule 
 of chalk and a smooth flint pebble, both of 
 which must have been left at some former 
 time on the surface, were found at this 
 depth. At from 11 to 12 inches beneath 
 the surface, the undisturbed reddish clay, full 
 of flints, extended. The appearance of the 
 above nodules of chalk surprised me much 
 at first, as they closely resembled water- 
 worn pebbles, whereas the freshly-broken 
 fragments had been angular. But on ex- 
 amining the nodules with a lens, they no 
 longer appeared water-worn, for their surfaces 
 were pitted through unequal corrosion, and 
 minute, sharp points, formed of broken fossil 
 shells, projected from them. It was evident 
 that the corners of the original fragments of 
 chalk had been wholly dissolved , from pre- 
 senting a large surface to the carbonic acid 
 dissolved in the rain-water and to that gener-
 
 CHAP. III. BROUGHT UP BY WORMS. 143 
 
 ated iii soil containing vegetable matter, as 
 well as to the humus-acids.* The projecting 
 corners would also, relatively to the other 
 parts, have been embraced by a larger num- 
 ber of living rootlets; and these have the 
 power of even attacking marble, as Sachs has 
 shown. Thus, in the course of 29 years, 
 buried angular fragments of chalk had been 
 converted into well-rounded nodules. 
 
 Another part of this same field was mossy, 
 and as it was thought that sifted coal- cinders 
 would improve the pasture, a thick layer was- 
 spread over this part either in 1842 or 1843 r 
 and another layer some years afterwards. 
 In 1871 a trench was here dug, and many 
 cinders lay in a line at a depth of 7 
 inches beneath the surface, with another line 
 at a depth of 5J inches parallel to the one 
 beneath. In another part of this field,, 
 which had formerly existed as a separate 
 one, and which it was believed had been 
 pasture-land for more than a century, trenches 
 were dug to see how thick the vegetable 
 mould was. By chance the first trench was 
 made at a spot where at some former period,. 
 
 * S. W. Johnson, How Crops Feed,' 1870, p. 139.
 
 144 AMOUNT OF EARTH CHAP. III. 
 
 certainly more than forty years before, a 
 large hole had been filled Tip with coarse red 
 clay, flints, fragments of chalk, and gravel ; 
 and here the fine vegetable mould was only 
 from 4-J- to 4| inches in thickness. In 
 another and undisturbed place, the mould 
 varied much in thickness, namely, from 6J 
 to 8 inches; beneath which a few small 
 fragments of brick were found in one 
 place. From these several cases, it would 
 appear that during the last 29 years mould 
 has been heaped on the surface at an 
 average annual rate of from '2 to *22 of an 
 inch. But in this district when a ploughed 
 field is first laid down in grass, the mould 
 accumulates at a much slower rate. The 
 rate, also, must become very much slower 
 after a bed of mould, several inches in thick- 
 ness, has been formed ; for the worms then 
 live chiefly near the surface, and burrow 
 down to a greater depth so as to bring up 
 fresh earth from below, only during the 
 winter when the weather is very cold (at 
 which time worms were found in this field at 
 a depth of 26 inches) and during summer, 
 when the weather is very dry.
 
 CHAP. IIL BROUGHT UP BY WORMS. 145 
 
 A field, which adjoins the one just de- 
 scribed, slopes in one part rather -steeply 
 (viz., at from 10 to 15) ; this part was last 
 ploughed in 1841, was then harrowed and 
 left to become pasture-land. For several 
 years it was clothed with an extremely scant 
 vegetation, and was so thickly covered with 
 small and large flints (some of them half as 
 large as a child's head) that the field was 
 always called by my sons " the stony field." 
 When they ran down the slope the stones 
 clattered together. I remember doubting 
 whether I should live to see these larger flints 
 covered with vegetable mould and turf. But 
 the smaller stones disappeared before many 
 years had elapsed, as did every one of the 
 larger ones after a time ; so that after thirty 
 years (1871) a horse could gallop over the 
 compact turf from one end of the field to the 
 other, and not strike a single stone with his 
 shoes. To anyone who remembered the 
 appearance of the field in 1842, the transfor- 
 mation was wonderful. This was certainly 
 the work of the worms, for though castings 
 were not frequent for several years, yet some 
 were thrown up month after month, and
 
 146 AMOUNT OF EARTH CHAP. III. 
 
 these gradually increased in numbers as the 
 pasture improved. In the year 1871 a 
 trench was dug on the above slope, and the 
 blades of grass were cut off close to the roots, 
 so that the thickness of the turf and of the 
 vegetable mould could be measured accur- 
 ately. The turf was rather less than half an 
 inch, and the mould, which did not contain 
 any stones, 2J inches in thickness. Beneath 
 this lay coarse clayey earth full of flints, like 
 that in any of the neighbouring ploughed 
 fields. This coarse earth easily fell apart 
 from the overlying mould when a spit was 
 lifted up. The average rate of accumulation 
 of the mould during the whole thirty years 
 was only "083 inch per year (i.e., nearly one 
 inch in twelve years) ; but the rate must 
 have been much slower at first, and after- 
 wards considerably quicker. 
 
 The transformation in the appearance of 
 this field, which had been effected beneath 
 my eyes, was afterwards rendered the more 
 striking, when I examined in Knole Park 
 a dense) forest of lofty beech-trees, beneath 
 which nothing grew. Here the ground was 
 thickly strewed with large naked stones, and
 
 CHAP. III. BROUGHT UP BY WORMS. 147 
 
 worm-castings were almost wholly absent. 
 Obscure lines and irregularities on the sur- 
 face indicated that the land had been cul- 
 tivated some centuries ago. It is probable 
 that a thick wood of young beech-trees 
 sprung up so quickly, that time enough was 
 not allowed for worms to cover up the stones 
 with their castings, before the site became 
 unfitted for their existence. Anyhow the con- 
 trast between the state of the now miscalled 
 " stony field," well stocked with worms, and 
 the present state of the ground beneath the 
 old beech-trees in Knole Park, where worms 
 appeared to be absent, was striking. 
 
 A narrow path running across part of my 
 lawn was paved in 1843 with small flag- 
 stones, set edgeways ; but worms threw up 
 many castings and weeds grew thickly be- 
 tween them. During several years the path 
 was weeded and swept; but ultimately the 
 weeds and worms prevailed, and the 
 gardener ceased to sweep, merely mowing off 
 the weeds, as often as the lawn was mowed. 
 The path soon became almost covered up, 
 and after several years no trace of it was 
 left. On removing, in 1877, the thin over-
 
 148 AMOUNT OF EAETH CHAP. III. 
 
 lying layer of turf, the small flag-stones, all 
 in their proper places, were found covered 
 by an inch of fine mould. 
 
 Two recently published accounts of sub- 
 stances strewed on the surface of pasture-land, 
 having become buried through the action of 
 worms, may be here noticed. The Rev. 
 H. C. Key had a ditch cut in a field, over 
 which coal-ashes had been spread, as it was 
 believed, eighteen years before; and on the 
 clean-cut perpendicular sides of the ditch, at a 
 depth of at least seven inches, there could be 
 seen, for a length of 60 yards, " a distinct, very 
 " even, narrow line of coal-ashes, mixed with 
 "small coal, perfectly parallel with the top- 
 " sward."* This parallelism and the length of 
 the section give interest to the case. Secondly, 
 Mr. Dancer statesf that crushed bones had been 
 thickly strewed over a field ; and " some years 
 " afterwards " these were found "several inches 
 " below the surface, at a uniform depth." 
 
 The Rev. Mr. Zincke informs me that he 
 has lately had an orchard dug to the unusual 
 depth of 4 feet. The upper 18 inches consisted 
 
 * ' Nature,' November 1877, p. 28. 
 
 t * Proc. Phil. Soc.' of Manchester, 1877, p. 247. 

 
 CHAP. III. BROUGHT UP BY WORMS. 149 
 
 of dark-coloured vegetable mould, and the 
 next 18 inches of sandy loam, containing in 
 the lower part many rolled pieces of sand- 
 stone, with some bits of brick and tile, probably 
 of Roman origin, as remains of this period 
 have been found close by. The sandy loam 
 rested on an indurated ferruginous pan of 
 yellow clay, on the surface of which two 
 perfect celts were found. If, as seems pro- 
 bable, the celts were originally left on the 
 surface of the land, they have since been 
 covered up with earth 3 feet in thickness, all 
 of which has probably passed through the 
 bodies of worms, excepting the stones which 
 may have been scattered on the surface at 
 different times, together with manure or by 
 other means. It is difficult otherwise to 
 understand the source of the 18 inches of 
 sandy loam, which differed from the overlying 
 dark vegetable mould, after both had been 
 burnt, only in being of a brighter red colour, 
 and in not being quite so fine-grained. But 
 on this view we must suppose that the carbon 
 in vegetable mould, when it lies at some little 
 depth beneath the surface and does not con- 
 tinually receive decaying vegetable matter 
 
 M 2
 
 150 AMOUNT OF EAKTH CHAP. III. 
 
 from above, loses its dark colour in the course 
 of centuries ; but whether this is probable I 
 do not know. 
 
 Worms appear to act in the same manner 
 in New Zealand as in Europe ; for Professor J. 
 von Haast has described * a section near the 
 coast, consisting of mica-schist, " covered by 
 "5 or 6 feet of loess, above which about 12 
 "inches of vegetable soil had accumulated." 
 Between the loess and the mould there was 
 a layer from 3 to 6 inches in thickness, 
 consisting of " cores, implements, flakes, and 
 " chips, all manufactured from hard basaltic 
 "rock." It is therefore probable that the 
 aborigines, at some former period, had left 
 these objects on the surface, and that they 
 had afterwards been slowly covered up by 
 the castings of worms. 
 
 Farmers in England are well aware that 
 objects of all kinds, left on the surface of 
 pasture-land, after a time disappear, or, as 
 they say, work themselves downwards. How 
 powdered lime, cinders, and heavy stones, 
 can work down, and at the same rate, 
 through the matted roots of a grass-covered 
 
 * Trans, of the New Zealand Institute,' vol. xii., 1880, p. 152.
 
 CHAP. III. BROUGHT UP BY WORMS. 151 
 
 surface, is a question which has probably 
 never occurred to them.* 
 
 The Sinking of great Stones through the 
 Action of Worms. When a stone of large 
 size and of irregular shape is left on the 
 surface of the ground, it rests, of course, 
 on the more protuberant parts ; but worms 
 soon fill up with their castings all the hollow 
 spaces on the lower side ; for, as Hensen re- 
 marks, they like the shelter of stones. As 
 soon as the hollows are filled up, the worms 
 eject the earth which they have swallowed 
 beyond the circumference of the stones ; 
 and thus the surface of the ground is raised 
 all round the stone. As the burrows ex- 
 cavated directly beneath the stone after a 
 time collapse, the stone sinks a little, t Hence 
 
 * Mr. Lindsay Carnagie, in a letter (June 1838) to Sir C. Lyell, 
 remarks that Scotch farmers are afraid of putting lime on 
 ploughed land until just before it is laid down for pasture, from 
 a belief that it has some tendency to sink. He adds : " Some 
 years since, in autumn, I laid lime on an oat-stubble and ploughed 
 it down ; thus bringing it into immediate contact with the dead 
 vegetable matter, and securing its thorough mixture through the 
 means of all the subsequent operations of fallow. In consequence 
 of the above prejudice, I was considered to have committed a 
 great fault ; but the result was eminently successful, and the 
 practice was partially followed. By means of Mr. Darwin's 
 observations, I think the prejudice will be removed." 
 
 f This conclusion, which, as we shall immediately see, is fully
 
 152 GKEAT STONES CHAP. HI. 
 
 it is, that boulders which at some ancient 
 period have rolled down from a rocky moun- 
 tain or cliff on to a meadow at its hase, are 
 always somewhat imbedded in the soil ; and, 
 when removed, leave an exact impression of 
 their lower surfaces in the underlying fine 
 mould. If, however, a boulder is of such 
 huge dimensions, that the earth beneath is 
 kept dry, such earth will not be inhabited 
 by worms, and the boulder will not sink 
 into the ground 
 
 A lime-kiln formerly stood in a grass-field 
 near Leith Hill Place in Surrey, and was 
 pulled down 35 years before my visit; 
 all the loose rubbish had been carted away, 
 excepting three large stones of quartzose 
 sandstone, which it was thought might here- 
 after be of some use. An old workman re- 
 membered that they had been left on a bare 
 surface of broken bricks and mortar, close to 
 the foundations of the kiln ; but the whole 
 surrounding surface is now covered with turf 
 and mould. The two largest of these stones 
 
 justified, is of some little importance, as the so-called bench-stones> 
 which surveyors fix in the ground as a record of their levels, 
 may in time become false standards. My son Horace intends at 
 some future period to ascertain how far this has occurred.
 
 CHAP. III. UNDERMINED BY WORMS. 153 
 
 had never since been moved ; nor could this 
 easily have been done, as, when I had them 
 removed, it was the work of two men with 
 levers. One of these stones, and not the 
 largest, was 64 inches long, 17 inches broad, 
 and from 9 to 10 inches in thickness. Its 
 lower surface was somewhat protuberant in 
 the middle ; and this part still rested on 
 broken bricks and mortar, showing the truth 
 of the old workman's account. Beneath the 
 brick rubbish the natural sandy soil, full of 
 fragments of sandstone was found ; and this 
 could have yielded very little, if at all, to 
 the weight of the stone, as might have been 
 expected if the sub-soil had been clay. The 
 surface of the field, for a distance of about 
 9 inches round the stone, gradually sloped up 
 to it, and close to the stone stood in most 
 places about 4 inches above the surrounding 
 ground. The base of the stone was buried 
 from 1 to 2 inches beneath the general level, 
 and the upper surface projected about 8 
 inches above this level, or about 4 inches 
 above the sloping border of turf. After the 
 removal of the stone it became evident that 
 one of its pointed ends must at first have 
 stood clear above the ground by some inches,
 
 154 GREAT STONES CHAP. III. 
 
 but its upper surface was now on a level 
 with the surrounding turf. When the stone 
 was removed, an exact cast of its lower 
 side, forming a shallow crateriform hollow, 
 was left, the inner surface of which consisted 
 of fine black mould, excepting where the 
 more protuberant parts rested on the brick- 
 rubbish. A transverse section of this stone, 
 together with its bed, drawn from measure- 
 
 Fig. 6. 
 
 Transverse section across a large stone, which had lain on a 
 grass-field for 35 years. A A, general level of the field. The 
 underlying brick rubbish has not been represented. Scale 
 i inch to one foot. 
 
 ments made after it had been displaced, is 
 here given on a scale of J inch to a foot 
 (Fig. 6). The turf-covered border which 
 sloped up to the stone, consisted of fine 
 vegetable mould, in one part 7 inches in 
 thickness. This evidently consisted of worm- 
 castings, several of which had been recently 
 ejected. The whole stone had sunk in the
 
 CHAP. in. UNDERMINED BY WORMS. 155 
 
 thirty-five years, as far as I could judge, 
 about H inch ; and this must have been due 
 to the brick-rubbish beneath the more pro- 
 tuberant parts having been undermined by 
 worms. At this rate the upper surface of the 
 stone, if it had been left undisturbed, would 
 have sunk to the general level of the field 
 in 247 years; but before this could have 
 occurred, some earth would have been washed 
 down by heavy rain from the castings on the 
 raised border of turf over the upper surface 
 of the stone. 
 
 The second stone was larger than the one 
 just described, viz., 67 inches in length, 39 in 
 breadth, and 15 in thickness. The lower 
 surface was nearly flat, so that the worms 
 must soon have been compelled to eject their 
 castings beyond its circumference. The stone 
 as a whole had sunk about 2 inches into the 
 ground. At this rate it won Id have required 
 262 years for its upper surface to have sunk 
 to the general level of the field. The up- 
 wardly sloping, turf-covered border round 
 the stone was broader than in the last case, 
 viz., from 14 to 16 inches; and why this 
 should be so, I could see no reason. In most 
 parts this border was not so high as in the
 
 156 GREAT STONES CHAP. III. 
 
 last case, viz., from 2 to 2J inches, but in one 
 place it was as much as 5J. Its average 
 height close to the stone was probably about 
 3 inches, and it thinned out to nothing. If 
 so, a layer of fine earth, 15 inches in breadth 
 and 1^ inch in average thickness, of sufficient 
 length to surround the whole of the much 
 elongated slab, must have been brought up 
 by the worms in chief part from beneath the 
 stone in the course of 35 years. This 
 amount would be amply sufficient to account 
 for its having sunk about 2 inches into the 
 ground ; more especially if we bear in mind 
 that a good deal of the finest earth would 
 have been washed by heavy rain from the 
 castings ejected on the sloping border down 
 to the level of the field. Some fresh castings 
 were seen close to the stone. Nevertheless, 
 on digging a large hole to a depth of 18 
 inches where the stone had lain, only two 
 worms and a few burrows were seen, although 
 the soil was damp and seemed favourable for 
 worms. There were some large colonies of 
 ants beneath the stone, and possibly since 
 their establishment the worms had decreased 
 in number. 
 
 The third stone was only about half as
 
 CHAP. III. UNDERMINED BY WORMS. 157 
 
 large as the others ; and two strong boys 
 could together have rolled it over. I have 
 no doubt that it had been rolled over at a 
 moderately recent time, for it now lay at 
 some distance from the two other stones at 
 the bottom of a little adjoining slope. It 
 rested also on fine earth, instead of partly on 
 brick-rubbish. In agreement with this con- 
 clusion, the raised surrounding border of 
 turf was only 1 inch high in some parts, and 
 2 inches in other parts. There were no 
 colonies of ants beneath this stone, and on 
 digging a hole where it had lain, several 
 burrows and worms were found. 
 
 At Stonehenge, some of the outer Druidical 
 stones are now prostrate, having fallen at a 
 remote but unknown period ; and these have 
 become buried to a moderate depth in the 
 ground. They are surrounded by sloping 
 borders of turf, on which recent castings were 
 seen. Close to one of these fallen stones, 
 which was 17 ft. long, 6 ft. broad, and 28 \ 
 inches thick, a hole was dug ; and here the 
 vegetable mould was at least 9^ inches in 
 thickness. At this depth a flint was found, 
 and a little higher up on one side of the hole 
 a fragment of glass. The base of the stone
 
 158 GREAT STONES CHAP. III. 
 
 lay about 9 inches beneath the level of the 
 surrounding ground, and its upper surface 
 19 inches above the ground. 
 
 A hole was also dug close to a second huge 
 stone, which in falling had broken into two 
 pieces; and this must have happened long 
 ago, judging from the weathered aspect of 
 the fractured ends. The base was buried to 
 a depth of 10 inches, as was ascertained by 
 driving an iron skewer horizontally into the 
 ground beneath it. The vegetable mould 
 forming the turf-covered sloping border round 
 the stone, on which many castings had re- 
 cently been ejected, was 10 inches in thick- 
 ness ; and most of this mould must have been 
 brought up by worms from beneath its base. 
 At a distance of 8 yards from the stone, the 
 mould was only 5^ inches in thickness (with 
 a piece of tobacco pipe at a depth of 4 inches), 
 and this rested on broken flint and chalk 
 which could not have easily yielded to the 
 pressure or weight of the stone. 
 
 A straight rod was fixed horizontally (by 
 the aid of a spirit-level) across a third fallen 
 stone, which was 7 feet 9 inches long ; and the 
 contour of the projecting parts and of the ad- 
 Coining ground, which was not quite level,
 
 CHAP. III. UNDERMINED BY WORMS. 159 
 
 was thus ascertained, as shown in the ac- 
 companying diagram (Fig. 7) on a scale of 
 ^ inch to a foot. The turf-covered border 
 sloped up to the stone on one side to a 
 height of 4 inches, and on the opposite side 
 to only 2 inches above the general level. 
 A hole was dug on the eastern side, and the 
 base of the stone was here found to lie at a 
 
 Grass 
 
 Fig. 7. 
 
 Section through one of the fallen Druidical stones at Stonehenge, 
 showing how much it had sunk into the ground. Scale inch 
 to 1 foot. 
 
 depth of 4 inches beneath the general level 
 of the ground, and of 8 inches beneath the 
 top of the sloping turf-covered border. 
 
 Sufficient evidence has now been given 
 showing that small objects left on the surface 
 of the land where worms abound soon get 
 buried, and that large stones sink slowly 
 downwards through the same means. Every
 
 160 GREAT STONES CHAP. III. 
 
 step of the process could be followed, from the 
 accidental deposition of a single casting on a 
 small object lying loose on the surface, to its 
 being entangled amidst the matted roots of 
 the turf, and lastly to its being imbedded in 
 the mould at various depths beneath the 
 surface. When the same field was re-ex- 
 amined after the interval of a few years, such 
 objects were found at a greater depth than 
 before. The straightness and regularity of 
 the lines formed by the imbedded objects, 
 and their parallelism with the surface of the 
 land, are the most striking features of the 
 case ; for this parallelism shows how equably 
 the worms must have worked; the result 
 being, however, partly the effect of the wash- 
 ing down of the fresh castings by rain. The 
 specific gravity of the objects does not affect 
 their rate of sinking, as could be seen by 
 porous cinders, burnt marl, chalk and quartz 
 pebbles, having all sunk to the same depth 
 within the same time. Considering the 
 nature of the substratum, which at Leith Hill 
 Place was sandy soil including many bits of 
 rock, and at Stonehenge, chalk-rubble with 
 broken flints; considering, also, the presence 
 of the turf-covered sloping border of mould
 
 CHAP. III. UNDERMINED BY WORMS. 161 
 
 round the great fragments of stone at both 
 these places, their sinking does not appear to 
 have been sensibly aided by their weight, 
 though this was considerable.* 
 
 On the number of worms which live within 
 a given space. We will now show, firstly, 
 what a vast number of worms live unseen by 
 us beneath our feet, and, secondly, the actual 
 weight of the earth which they bring up to 
 the surface within a given space and within 
 a given time. Hensen, who has published so 
 full and interesting an account of the habits 
 of worms,f calculates, from the number which 
 he found in a measured space, that there must 
 exist 133,000 living worms in a hectare of 
 land, or 53,767 in an acre. This latter 
 number of worms would weigh 356 pounds, 
 taking Hensen's standard of the weight of a 
 single worm, namely, three grams. It should, 
 however, be noted that this calculation is 
 
 * Mr. R. Mallet remarks (' Quarterly Journal of Geolog. Soc.' 
 vol. xxxiii., 1877, p. 745) that " the extent to which the ground 
 beneath the foundations of ponderous architectural structures, 
 such as cathedral towers, has been known to become compressed, 
 is as remarkable as it is instructive and curious. The amount 
 of depression in some cases may be measured by feet." He 
 instances the Tower of Pisa, but adds that it was founded on 
 
 f ' Zeitschrift fur wissensch. Zoolog.' Bd.xxviii., 1877, p. 360.
 
 162 WEIGHT OF EAKTH CHAP. III. 
 
 founded on the numbers found in a garden, 
 and Hensen believes that worms are here 
 twice as numerous as in corn-fields. The 
 above result, astonishing though it be, seems 
 to me credible, judging from the number of 
 worms which I have sometimes seen, and 
 from the number daily destroyed by birds 
 without the species being exterminated. 
 Some barrels of bad ale were left on Mr. 
 Miller's land,* in the hope of making vinegar, 
 but the vinegar proved bad, and the barrels 
 were upset. It should be premised that acetic 
 acid is so deadly a poison to worms that 
 Perrier found that a glass rod dipped into 
 this acid and then into a considerable body of 
 water in which worms were immersed, in- 
 variably killed them quickly. On the morn- 
 ing after the barrels had been upset, " the 
 " heaps of worms which lay dead on the 
 " ground were so amazing, that if Mr. Miller 
 " had not seen them, he could not have 
 "thought it possible for such numbers to 
 " have existed in the space." As further evi- 
 dence of the large number of worms which 
 live in the ground, Hensen states that he 
 
 * See Mr. Dancer's paper in Proc. PhiL Soc. of Manchester/' 
 1877, p. 248.
 
 CHAP. III. BROUGHT UP BY WORMS. 163: 
 
 found in a garden sixty-four open burrows in 
 a space of 14i square feet, that is, nine in 
 2 square feet. But the burrows are some- 
 times much more numerous, for when digging 
 in a grass-field near Maer Hall, I found a 
 cake of dry earth, as large as my two open 
 hands, which was penetrated by seven bur- 
 rows, as large as goose-quills. 
 
 Weight of the earth ejected from a single 
 burrow, and from all the burrows within a 
 given space. With respect to the weight of 
 the earth daily ejected by worms, Hensen 
 found that it amounted, in the case of some 
 worms which he kept in confinement, and 
 which he appears to have fed with leaves, to- 
 only 0*5 gram, or less than 8 grains per 
 diem. But a very much larger amount 
 must be ejected by worms in their natural 
 state, at the periods when they consume earth 
 as food instead of leaves, and when they are 
 making deep burrows. This is rendered 
 almost certain by the following weights of the 
 castings thrown up at the mouths of single 
 burrows ; the whole of which appeared to 
 have been ejected within no long time, as was 
 certainly the case in several instances. The
 
 164 WEIGHT OF EARTH CHAP. III. 
 
 castings were dried (excepting in one specified 
 instance) by exposure during many days to 
 the sun or before a hot fire. 
 WEIGHT OF THE CASTINGS ACCUMULATED AT THE MOUTH 
 
 OF A SINGLE BuBBOW. 
 
 Ounces 
 
 (1.) Down, Kent (sub-soil red clay, full of flints, over- 
 lying the chalk). The largest casting which I 
 could find on the flanks of a steep valley, the 3 '98 
 sub-soil being here shallow. In this one case, the 
 casting was not well dried 
 
 (2.) Down. Largest casting which I could find (con-] 
 sisting chiefly of calcareous matter), on extremely I -3.07 
 poor pasture land at the bottom of the valley! 
 mentioned under (1.) .. .. .. ..' 
 
 (3.) Down. A large casting, but not of unusual size,) 
 
 from a nearly level field, poor pasture, laid down in / 1 * 22 
 grass about 35 years before . . . . . . . . ) 
 
 (4.) Down. Average weight of 11 not large castings j 
 
 ejected on a sloping surface on my lawn, after they! Q - 
 had suffered some loss of weight from being exposed j 
 during a considerable length of time to rain . . J 
 
 (5.) Near Nice in France. Average weight of 12' 
 castings of ordinary dimensions, collected by Dr. 
 King on land which had not been mown for a long 
 time and where worms abounded, viz., a lawn pro- 
 tected by shrubberies, near the sea ; soil sandy and 1*37 
 calcareous ; these castings had been exposed for some 
 time to rain, before being collected, and must have 
 lost some weight by disintegration, but they still re- 
 tained their form 
 
 (6.) The heaviest of the above twelve castings .. 1*76 
 
 '7.) Lower Bengal. Average weight of 22 castings, 
 collected by Mr. J. Scott, and stated by him to have 1 24 
 been thrown up in the course of one or two nights 
 
 (8.) The heaviest of the above 22 castings .. .. 2'09 
 
 (9.) Nilgiri Mountains, S. India ; average weight of-j 
 
 the 5 largest castings collected by Dr. King. They! 3>15 
 had been exposed to the rain of the last monsoon, j 
 and must have lost some weight .. .. .. J 
 
 (10.) The heaviest of the above 5 castings .. .. 4-34 
 
 In thi& table we see that castings which had
 
 CHAP. III. BEOUGHT UP BY WORMS. 165 
 
 been ejected at the mouth of the same burrow, 
 and which in most cases appeared fresh and 
 always retained their vermiform configuration, 
 generally exceeded an ounce in weight after 
 being dried, and sometimes nearly equalled a 
 quarter of a pound. On the Nilgiri moun- 
 tains one casting even exceeded this latter 
 weight. The largest castings in England 
 were found on extremely poor pasture-land; 
 and these, as far as I have seen, are generally 
 larger than those on land producing a rich 
 vegetation. It would appear that worms 
 have to swallow a greater amount of earth 
 on poor than on rich land, in order to obtain 
 sufficient nutriment. 
 
 With respect to the tower-like castings 
 near Nice (Nos. 5 and 6 in the above table), 
 Dr. King often found five or six of them on 
 a square foot of surface ; and these, judging 
 from their average weight, would have 
 weighed together 7^ ounces; so that the 
 weight of those on a square yard would 
 have been 41b. 3oz, Dr. King collected, 
 near the close of the year 1872, all the 
 castings which still retained their vermiform 
 shape, whether broken down or not, from a 
 
 N 2
 
 166 WEIGHT OF EARTH CHAP. IIL 
 
 square foot, in a place abounding with worms, 
 on the summit of a bank, where no castings 
 could have rolled down from above. These 
 castings must have been ejected, as he judged 
 from their appearance in reference to the 
 rainy and dry periods near Nice, within the 
 previous five or six months ; they weighed 
 9|oz., or 5 Ib. 5^oz. per square yard. After 
 an interval of four months, Dr. King collected 
 all the castings subsequently ejected on the 
 same square foot of surface, and they weighed 
 2J oz., or 1 Ib. 6^ oz. per square yard. 
 Therefore within about ten months, or we 
 will say for safety's sake within a year, 12 oz. 
 of castings were thrown up on this one 
 square foot, or 6*75 pounds on the square 
 yard ; and this would give 14*58 tons per 
 acre. 
 
 In a field at the bottom of a valley in the 
 chalk (see No. 2 in the foregoing table), a 
 square yard was measured at a spot where 
 very large castings abounded ; they appeared, 
 however, almost equally numerous in a few 
 other places. These castings, which retained 
 perfectly their vermiform shape, were col- 
 lected ; and they weighed when partially 
 dried, 1 Ib. 13J oz. This field had been
 
 CH*P. III. BROUGHT UP BY WORMS. 167 
 
 rolled with a heavy agricultural roller fifty-two 
 days before, and this would certainly have 
 flattened every single casting on the land. 
 The weather had been very dry for two or 
 three weeks before the day of collection, so 
 that not one casting appeared fresh or had 
 been recently ejected. We may therefore 
 assume that those which were weighed had 
 been ejected within, we will say, forty days 
 from the time when the field was rolled, 
 that is, twelve days short of the whole inter- 
 vening period. I had examined the same 
 part of the field shortly before it was rolled, 
 and it then abounded with fresh castings. 
 Worms do not work in dry weather during 
 the summer, or in winter during severe frosts. 
 If we assume that they work for only half 
 the year though this is too low an estimate 
 then the worms in this field would eject 
 during the year, 8'38 7 pounds per square yard ; 
 or 18' 12 tons per acre, assuming the whole 
 surface to be equally productive in castings. 
 
 In the foregoing cases some of the 
 necessary data had to be estimated, but in 
 the two following cases the results are much 
 more trustworthy. A lady, on whose ac- 
 curacy I can implicitly rely, offered to collect
 
 168 WEIGHT OF EAETH CHAP. III. 
 
 during a year all the castings thrown up on 
 two separate square yards, near Leith Hill 
 Place, in Surrey. The amount collected was, 
 however, somewhat less than that originally 
 ejected by the worms ; for, as I have repeatedly 
 observed, a good deal of the finest earth is 
 washed away, whenever castings are thrown up 
 during or shortly before heavy rain. Small 
 portions also adhered to the surrounding 
 blades of grass, and it required too much 
 time to detach every one of them. On 
 sandy soil, as in the present instance, castings 
 are liable to crumble after dry weather, and 
 particles were thus often lost. The lady also 
 occasionally left home for a week or two, and 
 at such times the castings must have suffered 
 still greater loss from exposure to the weather. 
 These losses were, however, compensated to 
 some extent by the collections having been 
 made on one of the squares for four days, and 
 on the other square for two days more than 
 the year. 
 
 A space was selected (October 9th, 1870) for 
 one of the squares on a broad, grass-covered 
 terrace, which had been mowed and swept 
 during many years. It faced the south, but
 
 CHAP. III. BROUGHT UP BY WORMS. 169 
 
 was shaded during part of the day by trees. 
 It had been formed at least a century ago by 
 a great accumulation of small and large frag- 
 ments of sandstone, together with some sandy 
 earth, rammed down level. It is probable that 
 it was at first protected by being covered with 
 turf. This terrace, judging from the number 
 of castings on it, was rather unfavourable for 
 the existence of worms, in comparison with 
 the neighbouring fields and an upper terrace. 
 It was indeed surprising that as many worms 
 could live here as were seen; for on digging 
 a hole in this terrace, the black vegetable 
 mould together with the turf was only four 
 inches in thickness, beneath which lay the 
 level surface of light-coloured sandy soil, with 
 many fragments of sandstone. Before any 
 castings were collected all the previously 
 existing ones were carefully removed. The 
 last day's collection was on October 14th, 
 1871. The castings were then well dried 
 before a fire ; and they weighed exactly 3^ Ibs. 
 This would give for an acre of similar land 
 7*56 tons of dry earth annually ejected by 
 worms. 
 
 The second square was marked on un-
 
 170 WEIGHT OF EARTH CHAP. IIL 
 
 enclosed common land, at a height of about 
 700 ft. above the sea, at some little distance 
 from Leith Hill Tower. The surface was 
 clothed with short, fine turf, and had never 
 -been disturbed by the hand of man. The 
 spot selected appeared neither particularly 
 favourable nor the reverse for worms ; but I 
 have often noticed that castings are especially 
 abundant on common land, and this may, 
 perhaps, be attributed to the poorness of 
 the soil. The vegetable mould was here 
 between three and four inches in thickness. 
 As this spot was at some distance from the 
 house where the lady lived, the castings were 
 not collected at such short intervals of time 
 as those on the terrace ; consequently the 
 loss of fine earth during rainy weather must 
 have been greater in this than in the last 
 case. The castings moreover were more 
 sandy, and in collecting them during dry 
 weather they sometimes crumbled into dust, 
 and much was thus lost. Therefore it is 
 certain that the worms brought up to the 
 surface considerably more earth than that 
 which was collected. The last collection 
 was made on October 27th, 1871 ; i.e., 367
 
 CHAP. III. BEOUGHT UP BY WORMS. 171 
 
 days after the square had been marked out 
 and the surface cleared of all pre-existing 
 castings. The collected castings, after being 
 well dried, weighed 7*453 pounds ; and this 
 would give, for an acre of the same kind of 
 land, 16'1 tons of annually ejected dry earth. 
 
 SUMMARY OF THE FOUR FOREGOING CASES. 
 
 (1.) Castings ejected near Nice within about a year, collected 
 by Dr. King on a square foot of surface, calculated to yield per 
 acre 14 '58 tons. 
 
 (2.) Castings ejected during about 40 days on a square yard, 
 in a field of poor pasture at the bottom of a large valley in the 
 Chalk, calculated to yield annually per acre 18 '12 tons. 
 
 (3.) Castings collected from a square yard on an old terrace at 
 Leith Hill Place, during 369 days, calculated to yield annually 
 per acre 7 "56 tons. 
 
 (4.) Castings collected from a square yard on Leith Hill 
 Common during 367 days, calculated to yield annually per acre 
 16-1 tons. 
 
 The thickness of the layer of mould, which 
 castings ejected during a year would form if 
 uniformly spread out. As we know, from 
 the two last cases in the above summary, the 
 weight of the dried castings ejected by worms 
 during a year on a square yard of surface, I 
 wished to learn how thick a layer of ordinary 
 mould this amount would form if spread uni- 
 formly over a square yard. The dry castings
 
 172 THICKNESS OF THE MOULD CHAP. III. 
 
 were therefore broken into small particles, 
 and whilst being placed in a measure were 
 well shaken and pressed down. Those col- 
 lected on the Terrace amounted to 124*77 
 cubic inches ; and this amount, if spread out 
 over a square yard, would make a layer 
 0*9627 inch in thickness. Those collected on 
 the Common amounted to 197*56 cubic inches, 
 and would make a similar layer *1524 inch in 
 thickness. 
 
 These thicknesses must, however, be cor- 
 rected, for the triturated castings, after being 
 well shaken down and pressed, did not make 
 nearly so compact a mass as vegetable mould, 
 though each separate particle was very 
 compact. Yet mould is far from being com- 
 pact, as is shown by the number of air- 
 bubbles which rise up when the surface is 
 flooded with water. It is moreover pene- 
 trated by many fine roots. To ascertain ap- 
 proximately by how much ordinary vegetable 
 mould would be increased in bulk by being 
 broken up into small particles and then dried, 
 a thin oblong block of somewhat argillaceous 
 mould (with the turf pared off) was measured 
 before being broken up, was well dried and
 
 CHAP. IIL ANNUALLY ACCUMULATED. 17S 
 
 again measured. The drying caused it to 
 shrink by ^ of its original bulk, judging from 
 exterior measurements alone. It was then 
 triturated and partly reduced to powder, in the 
 same manner as the castings had been treated, 
 and its bulk now exceeded (notwithstanding 
 shrinkage from drying) by -j^g- that of the 
 original block of damp mould. Therefore the 
 above calculated thickness of the layer, formed 
 by the castings from the Terrace, after being 
 damped and spread over a square yard, would 
 have to be reduced by T ^-; and this will 
 reduce the layer to '09 of an inch, so that a 
 layer '9 inch in thickness would be formed in 
 the course of ten years. On the same prin- 
 ciple the castings from the Common would 
 make in the course of a single year a layer 
 1429 inch, or in the course of 10 years 1*429 
 inch, in thickness. We may say in round 
 numbers that the thickness in the former case 
 rould amount to nearly 1 inch, and in- the 
 second case to nearly 1J inch in 10 years. 
 
 In order to compare these results with 
 those deduced from the rates at which small 
 objects left on the surfaces of grass-fields 
 become buried (as described in the early part
 
 174 THICKNESS OF THE MOULD CHAP. III. 
 
 of this chapter), we will give the following 
 summary : 
 
 SUMMARY OF THE THICKNESS OF THE MOULD ACCUMULATED 
 OVER OBJECTS LEFT STREWED ON THE SURFACE, IN THE 
 COURSE OF TEN YEARS. 
 
 The accumulation of mould during 14f years on the surface 
 of a dry, sandy, grass-field near Maer Hall, amounted to 2'2 
 inches in 10 years. 
 
 The accumulation during 21i years on a swampy field near 
 Maer Hall, amounted to nearly 1'9 inch in 10 years. 
 
 The accumulation during 7 years on a very swampy field near 
 Maer Hall amounted to 2 1 inches in 10 years. 
 
 The accumulation during 29 years, on good, argillaceous 
 pasture-land over the Chalk at Down, amounted to 2*2 inches in 
 10 years. 
 
 The accumulation during 30 years on the side of a valley over 
 the Chalk at Down, the soil being argillaceous, very poor, and 
 only just converted into pasture (so that it was for some years 
 unfavourable for worms), amounted to P 83 inch in 10 years. 
 
 In these cases (excepting the last) it may 
 be seen that the amount of earth brought 
 to the surface during 10 years is somewhat 
 greater than that calculated from the castings 
 which were actually weighed. This excess 
 may be partly accounted for by the loss which 
 the weighed castings had previously under- 
 gone through being washed by rain, by the 
 adhesion of particles to the blades of the sur- 
 rounding grass, and by their crumbling when 
 dry. Nor must we overlook other agencies
 
 CHAP. III. ANNUALLY ACCUMULATED. 175 
 
 which in all ordinary cases add to the 
 amount of mould, and which would not be 
 included in the castings that were collected, 
 namely, the fine earth brought up to the 
 surface by burrowing larvse and insects, espe- 
 cially by ants. The earth brought up by moles 
 generally has a somewhat different appearance 
 from vegetable mould ; but after a time would 
 not be distinguishable from it. In dry coun- 
 tries, moreover, the wind plays an important 
 part in carrying dust from one place to another, 
 and even in England it must add to the mould 
 on fields near great roads. But in our country 
 these latter several agencies appear to be of 
 quite subordinate importance in comparison 
 with the action of worms. 
 
 We have no means of judging how great a 
 weight of earth a single full-sized worm ejects 
 during a year. Hensen estimates that 53,767 
 worms exist in an acre of land; but this is 
 founded on the number found in gardens, and 
 he believes that only about half as many live 
 in corn-fields. How many live in old pasture 
 land is unknown ; but if we assume that half 
 the above number, or 26,886 worms live on 
 such land, then taking from the previous
 
 176 THICKNESS OF THE MOULD CHAP. III. 
 
 summary 15 tons as the weight of the castings 
 annually thrown up on an acre of land, each 
 worm must annually eject 20 ounces. A full- 
 sized casting at the mouth of a single burrow 
 often exceeds, as we have seen, an ounce in 
 weight ; and it is probable that worms eject 
 more than 20 full-sized castings during a 
 year. If they eject annually more than 20 
 ounces, we may infer that the worms which 
 live in an acre of pasture land must be less 
 than 26,886 in number. 
 
 "Worms live chiefly in the superficial mould, 
 which is usually from 4 or 5 to 10 and even 
 12 inches in thickness; and it is this mould 
 which passes over and over again through 
 their bodies and is brought to the surface. 
 But worms occasionally burrow into the sub- 
 soil to a much greater depth, and on such 
 occasions they bring up earth from this 
 greater depth ; and this process has gone on 
 for countless ages. Therefore the superficial 
 layer of mould would ultimately attain, 
 though at a slower and slower rate, a thick- 
 ness equal to the depth to which worms 
 ever burrow, were there not other opposing 
 agencies at work which carry away to a
 
 CHAP. III. ANNUALLY ACCUMULATED. 177 
 
 lower level some of the finest earth which is 
 continually being brought to the surface by- 
 worms. How great a thickness vegetable 
 mould ever attains, I have not had good 
 opportunities for observing; but in the next 
 chapter, when we consider the burial of 
 ancient buildings, some facts will be given on 
 this head. In the two last chapters we 
 shall see that the soil is actually increased, 
 though only to a small degree, through the 
 agency of worms; but .their chief work is 
 to sift the finer from the coarser particles, to 
 mingle the whole with, vegetable debris, and 
 to saturate it with their intestinal secretions. 
 
 Finally, no one who considers the facts 
 given in this chapter on the burying of 
 small objects and on the sinking of great 
 stones left on the surface on the vast 
 number of worms which live within a 
 moderate extent of ground on the weight of 
 the castings ejected from the mouth of the 
 same burrow on the weight of all the cast- 
 ings ejected within a known time on a measured 
 space will hereafter, as I believe, doubt that 
 worms play an important part in nature.
 
 178 BURIAL OF THE REMAINS CHAP. IV. 
 
 CHAPTER IV. 
 
 THE PART WHICH WORMS HAVE PLAYED IN 
 THE BURIAL OF ANCIENT BUILDINGS. 
 
 The accumulation of rubbish on the sites of great cities inde- 
 pendent of the action of worms The burial of a Roman villa 
 at Abinger The floors and walls penetrated by worms 
 Subsidence of a modern pavement The buried pavement at 
 Beaulieu Abbey Roman villas at Chedworth and Brading 
 The remains of the Roman town at Silchester The nature of 
 the debris by which the remains are covered The penetration 
 of the tesselated floors and walls by worms Subsidence of 
 the floors Thickness of the mould The old Roman city of 
 "Wroxeter Thickness of the mould Depth of the foundations 
 of some of the Buildings Conclusion. 
 
 ARCHAEOLOGISTS are probably not aware how 
 much they owe to worms for the preservation 
 of many ancient objects. Coins, gold orna- 
 ments, stone implements, &c., if dropped on 
 the surface of the ground, will infallibly be 
 buried by the castings of worms in a few 
 years, and will thus be safely preserved, until 
 the land at some future time is turned up. 
 For instance, many years ago a grass-field
 
 CHAP. IV. OF ANCIENT BUILDINGS. 179 
 
 was ploughed on the northern side of the 
 Severn, not far from Shrewsbury ; and a 
 surprising number of iron arrow-heads were 
 found at the bottom of the furrows, which, as 
 Mr. Blakeway, a local antiquary, believed, 
 were relics of the battle of Shrewsbury in the 
 year 1403, and no doubt had been originally 
 left strewed on the battle-field. In the 
 present chapter I shall show that not only 
 implements, &c., are thus preserved, but that 
 the floors and the remains of many ancient 
 buildings in England have been buried so 
 effectually, in large part through the action 
 of worms, that they have been discovered in 
 recent times solely through various accidents. 
 The enormous beds of rubbish, several yards 
 in thickness, which underlie many cities, 
 such as Eome, Paris, and London, the lower 
 ones being of great antiquity, are not here 
 referred to, as they have not been in any 
 way acted on by worms. When we con- 
 sider how much matter is daily brought into 
 a great city for building, fuel, clothing and 
 food, and that in old times when the roads 
 were bad and the work of the scavenger 
 was neglected, a comparatively small amount 
 
 o
 
 180 BURIAL OF THE REMAINS CHAP. IV. 
 
 was carried away, we may agree with 
 Elie de Beaumont, who, in discussing this 
 subject, says, " pour une voiture de materiaux 
 " qui en sort, on y en fait entrer cent." * Nor 
 should we overlook the effects of fires, the 
 demolition of old buildings, and the removal 
 of rubbish to the nearest vacant space. 
 
 AUnger, Surrey. Late in the autumn of 
 1876, the ground in an old farm-yard at this 
 place was dug to a depth of 2 to 2^ feet, and 
 the workmen found various ancient remains. 
 This led Mr. T. H. Farrer of Abinger Hall to 
 have an adjoining ploughed field searched. 
 On a trench being dug, a layer of concrete, 
 still partly covered with tesserae (small red 
 tiles), and surrounded on two sides by broken- 
 down walls, was soon discovered. Ift is 
 believed f that this room formed part of the 
 atrium or reception-room of a Roman villa. 
 The walls of two. or three other small rooms 
 were afterwards discovered. Many fragments 
 of pottery, other objects, and coins of several 
 
 * ' Lecons de Geologic pratique,' 1845, p. 142. 
 
 t A short account of this discovery was published in ' The 
 Times' of January 2, 1879; and a fuller account in 'The 
 Builder,' January 5, 1878.
 
 CHAP. IV. OF ANCIENT BUILDINGS. 181 
 
 Roman emperors, dating from 133 to 361, and 
 perhaps to 375 A.D., were likewise found. 
 Also a half-penny of George I., 1715. The 
 presence of this latter coin seems an anomaly ; 
 but no douht it was dropped on the ground 
 during the last century, and since then there 
 has been ample time for its burial under a 
 considerable depth of the castings of worms. 
 From the different dates of the Roman coins 
 we may infer that the building was long 
 inhabited. It was probably ruined and 
 deserted 1400 or 1500 years ago. 
 
 I was present during the commencement of 
 the excavations (August 20, 1877) and Mr. 
 Farrer had two deep trenches dug at opposite 
 ends of the atrium, so that I might examine 
 the nature of the soil near the remains. 
 The field sloped from east to west at an angle 
 of about 7 ; and one of the two trenches, 
 shown in the accompanying section (Fig. 8) 
 was at the upper or eastern end. The 
 diagram is on a scale of ^j of an inch to an 
 inch ; but the trench, which was between 4 
 and 5 feet broad, and in parts above 5 feet 
 deep, has necessarily been reduced out of all 
 proportion. - The fine mould over the floor 
 
 o 2
 
 :182 
 
 BURIAL OF THE REMAINS CHAP. IV. 
 
 Fig. 8. 
 
 Section through the foundations of a buried Roman villa at 
 Abinger. A A, vegetable mould ; B, dark earth full of stones, 
 13 inches in thickness ; C, black mould ; D, broken mortar ; 
 E, black mould; F F, undisturbed sub-soil; G, tessera ; H, 
 concrete ; I, nature unknown ; \V, buried wall.
 
 CHAP. IV. OF ANCIENT BUILDINGS. 183 '> 
 
 of the atrium varied in thickness from 11 
 to 16 inches; and on the side of the trench in. 
 the section was a little over 13 inches. After 
 the mould had been removed, the floor 
 appeared as a whole moderately level ; but it 
 sloped in parts at an angle of 1, and in one- 
 place near the outside at as much as 8 30', 
 The wall surrounding the pavement was- 
 built of rough stones, and was 23 inches in: 
 thickness where the trench was dug. Its 
 broken summit was here 13 inches, but in 
 another part 15 inches, beneath the surface of 
 the field, being covered by this thickness of 
 mould. In one spot, however, it rose to- 
 within 6 inches of the surface. On two- 
 sides of the room, where the junction of the- 
 concrete floor with the bounding walls could 
 be carefully examined, there was no crack or 
 separation. This trench afterwards proved* 
 to have been dug within an adjoining room 
 (11 ft. by 11 ft. 6 in. in size), the existence of 
 which was not even suspected whilst I was 
 present. 
 
 On the side of the trench farthest from the 
 buried wall (W), the mould varied from 9 to 
 14 inches in thickness ; it rested on a mass (B)
 
 4 
 184 BURIAL OP THE REMAINS CHAP. IV. 
 
 23 inches thick of blackish earth, including 
 many large stones. Beneath this was a thin 
 bed of very black mould (C), then a layer of 
 earth full of fragments of mortar (D), and 
 then another thin bed (about 3 inches thick) 
 (E) of very black mould, which rested on the 
 undisturbed subsoil (F) of firm, yellowish, 
 argillaceous sand. The 23-inch bed (B) was 
 probably made ground, as this would have 
 brought up the floor of the room to a level 
 with that of the atrium. The two thin beds 
 of black mould at the bottom of the trench 
 evidently marked two former land-surfaces. 
 Outside the walls of the northern room, many 
 bones, ashes, oyster-shells, broken pottery and 
 an entire pot were subsequently found at a 
 depth of 1 6 inches beneath the surface. 
 
 The second trench was dug on the western 
 or lower side of the villa: the mould was 
 here only 6J inches in thickness, and it 
 rested on a mass of fine earth full of stones, 
 broken tiles and fragments of mortar, 34 
 inches in thickness, beneath which was the 
 undisturbed sand. Most of this earth had 
 probably been washed down from the upper 
 part of the field, and the fragments of
 
 CHAP. IV. OP ANCIENT BUILDINGS. 185 
 
 stones, tiles, &c., must have come from the 
 immediately adjoining ruins. 
 
 It appears at first sight a surprising fact 
 that this field of light sandy soil should have 
 been cultivated and ploughed during many 
 years, and that not a vestige of these buildings 
 should have been discovered. No one even 
 suspected that the remains of a Roman 
 villa lay hidden close beneath the surface. 
 But the fact is less surprising when it is 
 known that the field, as the bailiff believed, 
 had never been ploughed to a greater depth 
 than 4 inches. It is certain that when the 
 land was first ploughed, the pavement and 
 the surrounding broken walls must have been 
 covered by at least 4 inches of soil, for other- 
 wise the rotten concrete floor would have 
 been scored by the ploughshare, the tessera 
 torn up, and the tops of the old walls 
 knocked down. 
 
 When the concrete and tesseras were first 
 cleared over a space of 14 by 9 ft., the floor 
 which was coated with trodden-down earth 
 exhibited no signs of having been penetrated 
 by worms ; and although the overlying fine 
 jnould closely resembled that which in many
 
 186 BURIAL OF THE REMAINS CHAP. IV, 
 
 places has certainly been accumulated by 
 worms, yet it seemed hardly possible that this 
 mould could have been brought up by worms 
 from beneath the apparently sound floor. It 
 seemed also extremely improbable that the 
 thick walls, surrounding the room and still 
 united to the concrete, had been undermined 
 by worms, and had thus been caused to sink, 
 being afterwards covered up by their cast- 
 ings. I therefore at first concluded that all 
 the fine mould above the ruins had been 
 washed down from the upper parts of the 
 field ; but we shall soon see that this conclu- 
 sion was certainly erroneous, though much 
 fine earth is known to be washed down from 
 the upper part of the field in its present 
 ploughed state during heavy rains. 
 
 Although the concrete floor did not at 
 first appear to have been anywhere pene- 
 trated by worms, yet by the next morning 
 little cakes of the trodden-down earth had 
 been lifted up by worms over the mouths of 
 seven burrows, which passed through the 
 softer parts of the naked concrete, or between 
 the interstices of the tesserae. On the third 
 morning twenty-five burrows were counted ;
 
 CHAP. IV. OF ANCIENT BUILDINGS. 187 
 
 and by suddenly lifting up the little cakes 
 of earth, four worms were seen in the act 
 of quickly retreating. Two castings were 
 thrown up during the third night on the 
 floor, and these were of large size. The 
 season was not favourable for the full activity 
 of worms, and the weather had lately been 
 hot and dry, so that most of the worms now 
 lived at a considerable depth. In digging 
 the two trenches many open burrows and 
 some worms were encountered at between 
 30 and 40 inches beneath the surface ; but at 
 a greater depth they became rare. One 
 worm, however, was cut through at 48 J, and 
 another at 51 J inches beneath the surface. 
 A fresh humus-lined burrow was also met 
 with at a depth of 57 and another at G5J 
 inches. At greater depths than this, neither 
 burrows nor worms were seen. 
 
 As I wished to learn how many worms 
 lived beneath the floor of the atrium a 
 space of about 14 by 9 feet Mr. Farrer 
 was so kind as to make observations for 
 me, during the next seven weeks, by which 
 time the worms in the surrounding country 
 were in full activity, and were working
 
 188 BURIAL OF THE REMAINS CHAP. IV. 
 
 near the surface. It is very improbable that 
 worms should have migrated from the adjoin- 
 ing field into the small space of the atrium, 
 :after the superficial mould in which they 
 prefer to live, had been removed. We may 
 iherefore conclude that the burrows and the 
 castings which were seen here during the 
 ensuing seven weeks were the work of the 
 former inhabitants of the space. I will now 
 give a few extracts from Mr. Farrer's notes. 
 
 Aug. 26th, 1877; that is, five days after 
 ihe floor had been cleared. On the previous 
 night there had been some heavy rain, which 
 washed the surface clean, and now the mouths 
 of forty burrows were counted. Parts of the 
 concrete were seen to be solid, and had never 
 been penetrated by worms, and here the rain- 
 water lodged. 
 
 Sept. 5th. Tracks of worms, made during 
 the previous night, could be seen on the sur- 
 face of the floor, and five or six vermiform 
 castings had been thrown up. These were 
 defaced. 
 
 Sept. 12th. During the last six days, the 
 worms have not been active, though many 
 castings have been ejected in the neighbour-
 
 HAP. IV. OF ANCIENT BUILDINGS. 189 
 
 ing fields ; but on this day the earth was a 
 little raised over the mouths of the burrows, 
 or castings were ejected, at ten fresh points. 
 These were defaced. It should be understood 
 that when a fresh burrow is spoken of, this 
 generally means only that an old burrow has 
 been re-opened. Mr. Farrer was repeatedly 
 struck with the pertinacity with which the 
 worms re-opened their old burrows, even when 
 no earth was ejected from them. I have 
 often observed the same fact, and generally 
 the mouths of the burrows are protected by 
 an accumulation of pebbles, sticks or leaves. 
 Mr. Farrer likewise observed that the worms 
 living beneath the floor of the atrium often 
 collected coarse grains of sand, and such little 
 stones as they could find, round the mouths 
 of their burrows. 
 
 Sept. 13th ; soft wet weather. The mouths 
 of the burrows were re-opened, or castings 
 were ejected, at 31 points; these were all 
 defaced. 
 
 Sept. 14th; 34 fresh holes or castings; 
 all defaced. 
 
 Sept. 15th ; 44 fresh holes, only 5 castings ; 
 all defaced.
 
 190 BUEIAL OF THE EEMAINS CHAP. IV. 
 
 Sept. 18th ; 43 fresh holes, 8 castings ; all 
 defaced. 
 
 The number of castings on the surrounding 
 fields was now very large 
 
 Sept. 19th; 40 holes, 8 castings; all 
 defaced. 
 
 Sept. 22nd. ; 43 holes, only a few fresh 
 castings ; all defaced. 
 
 Sept. 23rd ; 44 holes, 8 castings. 
 
 Sept. 25th ; 50 holes, no record of the 
 number of castings. 
 
 Oct. 13th ; 61 holes, no record of the 
 number of castings. 
 
 After an interval of three years, Mr. Farrer, 
 at my request, again looked at the concrete 
 floor, and found the worms still at work. 
 
 Knowing what great muscular power worms 
 possess, and seeing how soft the concrete was- 
 in many parts, I was not surprised at its 
 having been penetrated by their burrows; 
 but it is a more surprising fact that the 
 mortar between the rough stones of the thick 
 walls, surrounding the rooms, was found by 
 Mr. Farrer to have been penetrated by worms. 
 On August 26th, that is, five days after the 
 ruins had been exposed, he observed four
 
 CHAP. IV. OF ANCIENT BUILDINGS. 191 
 
 open burrows on the broken summit of the 
 eastern wall (W in Fig. 8) ; and, on Septem- 
 ber 15th, other burrows similarly situated 
 were seen. -It should also be noted that in 
 the perpendicular side of the trench (which 
 was much deeper than is represented in 
 Fig. 8) three recent burrows were seen, which 
 ran obliquely far down beneath the base of 
 the old wall. 
 
 We thus see that many worms lived beneath 
 the floor and the walls of the atrium at the 
 time when the excavations were made ; and 
 that they afterwards almost daily brought up 
 earth to the surface from a considerable 
 depth. There is not the slightest reason to 
 doubt that worms have acted in this manner 
 ever since the period when the concrete was 
 sufficiently decayed to allow them to penetrate 
 it; and even before that period they would 
 have lived beneath the floor, as soon as it 
 became pervious to rain, so that the soil 
 beneath was kept damp. The floor and the 
 walls must therefore have been continually 
 undermined ; and fine earth must have been 
 heaped on them during many centuries, 
 perhaps for a thousand years. If the burrows
 
 192 BUKIAL OF THE EEMAINS CHAP. IV 
 
 beneath the floor and walls, which it is prob- 
 able were formerly as numerous as they now 
 are, had not collapsed in the course of time 
 in the manner formerly explained, the under- 
 lying earth would have been riddled with pas- 
 sages like a sponge ; and as this was not 
 the case, we may feel sure that they have 
 collapsed. The inevitable result of such col- 
 lapsing during successive centuries, will have 
 been the slow subsidence of the floor and of the 
 walls, and their burial beneath the accumu- 
 lated worm-castings. The subsidence of a 
 floor, whilst it still remains nearly horizontal,, 
 may at first appear improbable ; but the case 
 presents no more real difficulty than that of 
 loose objects strewed on the surface of a field, 
 which, as we have seen, become buried several 
 inches beneath the surface in the course of a 
 few years, though still forming a horizontal 
 layer parallel to the surface. The burial of 
 the paved and level path on my lawn, which 
 took place under my own observation, is an 
 analogous case. Even those parts of the- 
 coricrete floor which the worms could not 
 penetrate would almost certainly have been 
 undermined, and would have sunk, like the great
 
 CHAP. IV. OF ANCIENT BUILDINGS. 193- 
 
 stones at Leith Hill Place and Stonehenge, 
 for the soil would have been damp beneath- 
 them. But the rate of sinking of the dif- 
 ferent parts would not have been quite equal, 
 and the floor was not quite level. The 
 foundations of the boundary walls lie, as 
 shown in the section, at a very small depth 
 beneath the surface ; they would therefore 
 have tended to subside at nearly the same 
 rate as the floor. But this would not have 
 occurred if the foundations had been deep, 
 as in the case of some other Roman ruins 
 presently to be described. 
 
 Finally, we may infer that a large part of 
 the fine vegetable mould, which covered the 
 floor and the broken-down walls of this villa, 
 in some places to a thickness of 16 inches, 
 was brought up from below by worms. From 
 facts hereafter to be given there can be no' 
 doubt that some of the finest earth thus 
 brought up will have been washed down the 
 sloping surface of the field during every heavy 
 shower of rain. If this had not occurred a 
 greater amount of mould would have accumu- 
 lated over the ruins than that now present. 
 But beside the castings of worms and some
 
 194 BURIAL OP THE REMAINS CHAP. IV. 
 
 earth brought up by insects, and some accu- 
 mulation of dust, much fine earth will have 
 been washed over the ruins from the upper 
 parts of the field, since it has been under 
 cultivation ; and from over the ruins to the 
 lower parts of the slope ; the present thick- 
 ness of the mould being the resultant of these 
 several agencies. 
 
 I may here append a modern instance of 
 the sinking of a pavement, communicated to 
 me in 1871 by Mr. Ramsay, Director of the 
 Geological Survey of England. A passage 
 without a roof, 7 feet in length by 3 feet 2 
 inches in width, led from his house into the 
 garden, and was paved with slabs of Portland 
 stone. Several of these slabs were 16 inches 
 square, others larger, and some a little smaller. 
 This pavement had subsided about 3 inches 
 along the middle of the passage, and two 
 inches on each side, as could be seen by the 
 lines of cement by which the slabs had been 
 originally joined to the walls. The pave- 
 ment had thus become slightly concave along 
 the middle; but there was no subsidence at 
 the end close to the house. Mr. Ramsay
 
 CHAP. IV OF ANCIENT BUILDINGS. 195 
 
 could not account for this sinking, until he 
 observed that castings of black mould were 
 frequently ejected along the lines of junction 
 between the slabs ; and these castings were 
 regularly swept away. The several lines of 
 junction, including those with the lateral 
 walls, were altogether 39 feet 2 inches in 
 length. The pavement did not present the- 
 appearance of ever having been renewed, 
 and the house was believed to have been 
 built about eighty-seven years ago. Con- 
 sidering all these circumstances, Mr. Ramsay 
 does not doubt that the earth brought up by 
 the worms since the pavement was first laid 
 down, or rather since the decay of the mortar 
 allowed the worms to burrow through it, and 
 therefore within a much shorter time than 
 the eighty-seven years, has sufficed to cause the 
 sinking of the pavement to the above amount, 
 except close to the house, where the ground 
 beneath would have been kept nearly dry. 
 
 Beaulieu Abbey, Hampshire. This abbey 
 was destroyed by Henry VIII., and there 
 now remains only a portion of the southern 
 aisle-wall. It is believed that the king had 
 most of the stones carried away for building 
 
 p
 
 196 BURIAL OF THE REMAINS CHAP. IV. 
 
 a castle ; and it is certain that they have been 
 removed. The positions of the nave and tran- 
 septs were ascertained not long ago by the 
 foundations having been found ; and the 
 place is now marked by stones let into 
 the ground. Where the abbey formerly 
 stood, there now extends a smooth grass- 
 covered surface, which resembles in all 
 respects the rest of the field. The guardian, 
 a very old man, said the surface had never 
 been levelled in his time. In the year 1853, 
 the Duke of Buccleuch had three holes dug 
 in the turf within a few yards of one another, 
 at the western end of the nave ; and the old 
 tesselated pavement of the abbey was thus 
 discovered. These holes were afterwards 
 surrounded by brickwork, and protected by 
 trap-doors, so that the pavement might be 
 readily inspected and preserved. When my 
 son William examined the place on January 
 5, 1872, he found that the pavement in the 
 three holes lay at depths of 6|, 10 and Hi 
 inches beneath the surrounding turf-covered 
 surface. The old guardian asserted that he 
 was often forced to remove worm-castings 
 from the pavement; and that he had done
 
 CHAP. IV. OF ANCIENT BUILDINGS. 197 
 
 so about six months before. My son collected 
 all from one of the holes, the area of which 
 was 5-32 square feet, and they weighed 7*97 
 ounces. Assuming that this amount had 
 accumulated in six months, the accumulation 
 during a year on a square yard would be 
 1*68 pounds, which, though a large amount, 
 is very small compared with what, as we 
 have seen, is often ejected on fields and 
 commons. When I visited the abbey on 
 June 22, 1877, the old man said that he had 
 cleared out the holes about a month before, 
 but a good many castings had since been 
 ejected. I suspect that he imagined that he 
 swept the pavements oftener than he really 
 did, for the conditions were in several re- 
 spects very unfavourable for the accumulation 
 of even a moderate amount of castings. The 
 tiles are rather large, viz., about 5i inches 
 square, and the mortar between them was in 
 most places sound, so that the worms were 
 able to bring up earth from below only at 
 certain points. The tiles rested on a bed of 
 concrete, and the castings in consequence con- 
 sisted in large part (viz., in the proportion 
 of 19 to 33) of particles of mortar, grains of 
 
 p 2
 
 198 BUEIAL OF THE REMAINS CHAP. IV. 
 
 sand, little fragments of rock, bricks or tile ; 
 and such substances could hardly be agreeable, 
 and certainly not nutritious, to worms. 
 
 My son dug holes in several places within 
 the former walls of the abbey, at a distance of 
 several yards from the above described 
 bricked squares. He did not find any tiles, 
 though these are known to occur in some 
 other parts, but he came in one spot to con- 
 crete on which tiles had once rested. The 
 fine mould beneath the turf on the sides of 
 the several holes, varied in thickness from 
 only 2 to 2 1 inches, and this rested on a layer 
 from 8| to above 11 inches in thickness, 
 consisting of fragments of mortar and stone- 
 rubbish with the interstices compactly filled 
 up with black mould. In the surrounding 
 field, at a distance of 20 yards from the 
 abbey, the fine vegetable mould was 11 inches 
 thick. 
 
 We may conclude from these facts that 
 when the abbey was destroyed and the stones 
 removed, a layer of rubbish was left over the 
 whole surface, and that as soon as the worms 
 were able to penetrate the decayed concrete 
 and the joints between the tiles, they slowly
 
 CHAP. IV. OF ANCIENT BUILDINGS. 199 
 
 filled up the interstices in the overlying 
 rubbish with their castings, which were after- 
 wards accumulated to a thickness of nearly 
 three inches over the whole surface. If we 
 add to this latter amount the mould between 
 the fragments of stones, some five or six 
 inches of mould must have been brought up 
 from beneath the concrete or tiles. The con- 
 crete or tiles will consequently have subsided 
 to nearly this amount. The bases of the 
 columns of the aisles are now buried beneath 
 mould and turf. It is not probable that 
 they can have been undermined by worms, 
 for their foundations would no doubt have 
 been laid at a considerable depth. If they 
 have not subsided, the stones of which the 
 columns were constructed must have been 
 removed from beneath the former level of 
 the floor. 
 
 Chedworth, Gloucestershire. The remains 
 of a large Roman villa were discovered here 
 in 1866, on ground which had been covered 
 with wood from time immemorial. No 
 suspicion seems ever to have been enter- 
 tained that ancient buildings lay buried here, 
 until a gamekeeper, in digging for rabbits, 

 
 200 BURIAL OF THE REMAINS CHAP. IY. 
 
 encountered some remains.* But subse- 
 quently the tops of some stone walls were de- 
 tected in parts of the wood, projecting a little 
 above the surface of the ground. Most of the 
 coins found here belonged to Constans (who 
 died 350 A.D.) and the Constantine family. 
 My sons Francis and Horace visited the 
 place in November 1877, for the sake of 
 ascertaining what part worms may have 
 played in the burial of these extensive re- 
 mains. But the circumstances were not 
 favourable for this object, as the ruins are sur- 
 rounded on three sides by rather steep banks, 
 down which earth is washed during rainy 
 weather. Moreover most of the old rooms 
 have been covered with roofs, for the pro- 
 tection of the elegant tesselated pavements. 
 
 A few facts may, however, be given on the 
 thickness of the soil over these ruins. Close 
 outside the northern rooms there is a broken 
 wall, the summit of which was covered by 5 
 
 * Several accounts of these ruins have been published ; the 
 best is by Mr. James Farrer in ' Proc. Soc. of Antiquaries of 
 Scotland,' vol. vi., Part II., 1867, p. 278. Also J. W. Grover, 
 'Journal of the British Arch. Assoc.' June 1866. Professor 
 Buckman has likewise published a pamphlet, 'Notes on the 
 Roman Villa at Chedworth,' 2nd edit. 1873 : Cirencester.
 
 CHAP. IV. OP ANCIENT BUILDINGS. 201 
 
 inches of black mould ; and in a hole dug on 
 the outer side of this wall, where the ground 
 had never before been disturbed, black mould, 
 full of stones, 26 inches in thickness, was 
 found, resting on the undisturbed sub-soil of 
 yellow clay. At a depth of 22 inches from 
 the surface a pig's jaw and a fragment of a 
 tile were found. When the excavations were 
 first made, some large trees grew over the 
 ruins; and the stump of one has been left 
 directly over a party-wall near the bath room, 
 for the sake of showing the thickness of the 
 superincumbent soil, which was here 38 
 inches. In one small room, which, after 
 being cleared out, had not been roofed over, 
 my sons observed the hole of a worm passing 
 through the rotten concrete, and a living 
 worm was found within the concrete. In 
 another open room worm-castings were seen 
 on the floor, over which some earth had by 
 this means been deposited, and here grass 
 now grew. 
 
 Brading, Isle of Wight. A fine Eoman 
 villa was discovered here in 1880 ; and by 
 the end of October no less than 18 chambers 
 had been more or less cleared. A coin dated
 
 202 BURIAL OF THE REMAINS CHAP. IV. 
 
 337 A.D. was found. My son William visited 
 the place before the excavations were com- 
 pleted ; and he informs me that most of the 
 floors were at first covered with much rubbish 
 and fallen stones, having their interstices 
 completely filled up with mould, abounding, 
 as the workmen said, with worms, above 
 which there was mould without any stones. 
 The whole mass was in most places from 3 
 to above 4 ft. in thickness. In one very 
 large room the overlying earth was only 
 2 ft. 6 in. thick ; and after this had been re- 
 moved, so many castings were thrown up 
 between the tiles that the surface had to 
 be almost daily swept. Most of the floors 
 were fairly level. The tops of the broken- 
 down walls were covered in some places by 
 only 4 or 5 inches of soil, so that they were 
 occasionally struck by the plough, but in 
 other places they were covered by from 13 
 to 18 inches of soil. It is not probable that 
 these walls could have been undermined by 
 worms and subsided, as they rested on a 
 foundation of very hard red sand, into which 
 worms could hardly burrow. The mortar, 
 however, between the stones of the walls of
 
 CHAP. IV. OF ANCIENT BUILDINGS. 203 
 
 a hypocaust was found by my son to have 
 been penetrated by many worm-burrows. 
 The remains of this villa stand on land which 
 slopes at an angle of about 3 ; and the land 
 appears to have been long cultivated. There- 
 fore no doubt a considerable quantity of fine 
 earth has been washed down from the upper 
 parts of the field, and has largely aided in 
 the burial of these remains. 
 
 Silchester, Hampshire. The ruins of this 
 small Roman town have been better pre- 
 served than any other remains of the kind 
 in England. A broken wall, in most parts 
 from 15 to 18 feet in height and about Ij 
 mile in compass, now surrounds a space of 
 about 100 acres of cultivated land, on which 
 a farm-house and a church stand.* Formerly, 
 when the weather was dry, the lines of the 
 buried walls could be traced by the appear- 
 ance of the crops ; and recently very exten- 
 sive excavations have been undertaken by 
 the Duke of Wellington, under the superin- 
 tendence of the late Kev. J. Gr. Joyce, by 
 which means many large buildings have been 
 
 * These details are taken from the 'Penny Cyclopaedia,' 
 article Hampshire.
 
 204 BURIAL OF THE REMAINS CHAP. IV. 
 
 discovered. Mr. Joyce made careful coloured 
 sections, and measured the thickness of each 
 bed of rubbish, whilst the excavations were in 
 progress ; and he has had the kindness to 
 send me copies of several of them. When 
 my sons Francis and Horace visited these 
 ruins, he accompanied them, and added his 
 notes to theirs. 
 
 Mr. Joyce estimates that the town was in- 
 habited by the Eomans for about three cen- 
 turies ; and no doubt much matter must have 
 accumulated within the walls during this long 
 period. It appears to have been destroyed 
 by fire, and most of the stones used in the 
 buildings have since been carried away. 
 These circumstances are unfavourable for as- 
 certaining the part which worms have played 
 in the burial of the ruins; but as careful 
 sections of the rubbish overlying an ancient 
 town have seldom or never before been made 
 in England, I will give copies of the most 
 characteristic portions of some of those made 
 by Mr. Joyce. They are of too great length 
 to be here introduced entire. 
 
 An east and west section, 30 ft. in length, 
 was made across a room in the Basilica, now
 
 CHAP. IV. 
 
 OF ANCIENT BUILDINGS. 
 
 205 
 
 called the Hall of the Merchants (Fig. 9). 
 The hard concrete floor, still covered here 
 and there with tesserae, was found at 3 ft. 
 
 Fig. 9. 
 Section within a room in the Basilica at Silchester. 
 
 Scale
 
 206 BUEIAL OF THE EEMAINS CHAP. IV. 
 
 beneath the surface of the field, which was 
 here level. On the floor there were two 
 large piles of charred wood, one alone of 
 which is shown in the part of the section 
 here given. This pile was covered by a thin 
 white layer of decayed stucco or plaster, 
 above which was a mass, presenting a singu- 
 larly disturbed appearance, of broken tiles, 
 mortar, rubbish and fine gravel, together 2*7 
 inches in thickness. Mr. Joyce believes that 
 the gravel was used in making the mortar 
 or concrete, which has since decayed, some 
 of the lime probably having been dissolved. 
 The disturbed state of the rubbish may have 
 been due to its having been searched for 
 building stones. This bed was capped by 
 fine vegetable mould, 9 inches in thickness. 
 From these facts we may conclude that the 
 Hall was burnt down, and that much rubbish 
 fell on the floor, through and from which the 
 worms slowly brought up the mould, now 
 forming the surface of the level field. 
 
 A section across the middle of another hall 
 in the Basilica, 32 feet 6 inches in length, 
 called the ^Erarium, is shown in Fig. 10. 
 It appears that we have here evidence of two
 
 CHAP. IY. 
 
 OF ANCIENT BUILDINGS. 
 
 207 
 
 fires, separated by an interval of time, during 
 which the 6 inches of " mortar and concrete 
 
 Fig. 10. 
 Section within a hall in the Basilica at Silchester. Scale Jj.
 
 208 BURIAL OF THE REMAINS CHAP. IV 
 
 with broken tiles " was accumulated. Be- 
 neath one of the layers of charred wood, a 
 valuable relic, a bronze eagle, was found; 
 and this shows that the soldiers must have 
 deserted the place in a panic. Owing to the 
 death of Mr. Joyce, I have not been able to 
 ascertain beneath which of the two layers the 
 eagle was found. The bed of rubble overly- 
 ing the undisturbed gravel originally formed, 
 as I suppose, the floor, for it stands on a level 
 with that of a corridor, outside the walls of 
 the Hall; but the corridor is not shown in the 
 section as here given. The vegetable mould 
 was 16 inches thick in the thickest part; and 
 the depth from the surface of the field, clothed 
 with herbage, to the undisturbed gravel, was 
 40 inches. 
 
 The section shown in Fig. 11 represents an 
 excavation made in the middle of the town, 
 and is here introduced because the bed of " rich 
 "mould" attained, according to Mr. Joyce, the 
 unusual thickness of 20 inches. Gravel lay 
 at the depth of 48 inches from the surface ; 
 but it was not ascertained whether this was 
 in its natural state, or had been brought here 
 and had been rammed down, as occurs in 
 f-ome other places.
 
 CHAP. IV. OF ANCIENT BUILDINGS. 209 
 
 The section shown in Fig. 12 was taken 
 in the centre of the Basilica, and though it was 
 5 feet in depth, the natural sub-soil was not 
 
 Mould, 20 inches 
 thick. 
 
 Rubble with broken 
 tiles, 4 inches thick. 
 
 Black decayed wood, 
 in thickest part 6 
 inches thick. 
 
 Section in a block of buildings in the middle of the town of 
 Silchester. 
 
 reached. The bed marked " concrete " was 
 probably at one time a floor; and the beds 
 beneath seem to be the remnants of more 
 ancient buildings. The vegetable mould was
 
 210 
 
 BURIAL OF THE EEMAINS CHAP. IV. 
 
 here only 9 inches thick, 
 sections, not copied, we 
 
 In some other 
 likewise have 
 
 Mould, 9 inches thick. 
 
 Light -coloured earth with 
 large pieces of broken 
 " tiles, 7 inches. 
 
 Dark, fine-grained rubbish 
 with small bits of tiles, 
 20 inches. 
 
 Concrete, 4 inches. 
 Stucco, 2 inches. 
 
 Made bottom with frag- 
 ments of tiles, 8 inches. 
 
 ne-grained made ground, 
 with the debris of older 
 buildings. 
 
 Fig. 12. 
 Section in the centre of the Basilica at Silchester. 
 
 evidence of buildings having been erected 
 over the ruins of older ones. In one case
 
 CHAP. IV. OF ANCIENT BUILDINGS. 211 
 
 there was a layer of yellow clay of very 
 unequal thickness between two beds of debris, 
 the lower one of which rested on a floor with 
 tesserae. The ancient broken walls appear to 
 have been sometimes roughly cut down to a 
 uniform level, so as to serve as the founda- 
 tions for a temporary building ; and Mr. Joyce 
 suspects that some of these buildings were 
 wattled sheds, plastered with clay, which 
 would account for the above-mentioned layer 
 of clay. 
 
 Turning now to the points which more 
 immediately concern us. Worm-castings 
 were observed on the floors of several of the 
 rooms, in one of which the tesselation was 
 unusually perfect. The tesserae here con- 
 sisted of little cubes of hard sandstone of 
 about 1 inch, several of which were loose 
 or projected slightly above the general level. 
 One or occasionally two open worm-burrows 
 were found beneath all the loose tesserae. 
 Worms have also penetrated the old walls of 
 these ruins. A wall, which had just been 
 exposed to view during the excavations then 
 in progress, was examined ; it was built of 
 large flints, and was 18 inches in thickness. 
 
 Q
 
 212 BURIAL OF THE REMAINS CHAP. IV. 
 
 it appeared sound, but when the soil was 
 removed from beneath, the mortar in the 
 lower part was found to be so much decayed 
 that the flints fell apart from their own 
 weight. Here, in the middle of the wall, at 
 a depth of 29 inches beneath the old floor and 
 of 49 J inches beneath the surface of the field, 
 a living worm was found, and the mortar was 
 penetrated by several burrows. 
 
 A second wall was exposed to view for the 
 first time, and an open burrow was seen on 
 its broken summit. By separating the flints 
 this burrow was traced far down in the 
 interior of the wall ; but as some of the flints 
 cohered firmly, the whole mass was disturbed 
 in pulling down the wall, and the burrow 
 could not be traced to the bottom. The 
 foundations of a third wall, which appeared 
 quite sound, lay at a depth of 4 feet beneath 
 one of the floors, and of course at a con- 
 siderably greater depth beneath the level of 
 the ground. A large flint was wrenched out 
 of the wall at about a foot from the base, 
 and this required much force, as the mortar 
 was sound ; but behind the flint in the 
 middle of the wall, the mortar was friable,
 
 CHAP. IV. OF ANCIENT BUILDINGS. 213 
 
 and here there were worm-burrows. Mr. 
 Joyce and my sons were surprised at the 
 blackness of the mortar in this and in several 
 other cases, and at the presence of mould in 
 the interior cf the walls. Some may have 
 been placed there by the old builders instead 
 of mortar ; but we should remember that 
 worms line their burrows with black humus. 
 Moreover open spaces would almost certainly 
 have been occasionally left between the large 
 irregular flints ; and these spaces, we may 
 feel sure, would be filled up by the worms 
 with their castings, as soon as they were able 
 to penetrate the wall. Eain-water, oozing 
 down the burrows would also carry fine 
 dark-coloured particles into every crevice. 
 Mr. Joyce was at first very sceptical about 
 the amount of work which I attributed to 
 worms ; but he ends his notes with reference 
 to the last-mentioned wall by saying, " This 
 " case caused me more surprise and brought 
 " more conviction to me than any other. I 
 "should have said, and did say, that it was 
 " quite impossible such a wa]l could have beer 
 " penetrated by earth-worms." 
 
 In almost all the rooms the pavement has 
 
 Q 2
 
 214 
 
 BURIAL OF THE REMAINS CHAP. IV. 
 
 
 
 i 
 
 I 
 
 2 I 
 
 sunk considerably, especi- 
 ally towards the middle; 
 and this is shown in the 
 three following sections. 
 The measurements were 
 made by stretching a string 
 tightly and horizontally 
 over the floor. The sec- 
 tion, Fig. 13, was taken 
 from north to south across 
 a room, 18 feet 4 inches in 
 length, with a nearly per- 
 fect pavement, next to the 
 "Bed Wooden Hut." In 
 the northern half, the sub- 
 sidence amounted to 5f 
 inches beneath the level of 
 the floor as it now stands 
 close to the walls; arid it 
 was greater in the northern 
 than in the southern half ; 
 but, according to Mr. Joyce, 
 the entire pavement has 
 obviously subsided. In 
 several places, the tesserae 
 appeared as if drawn a little 
 away from the walls ; whilst
 
 CHAP. IV OF ANCIENT BUILDINGS. 215 
 
 in other places they were still in close contact 
 with them. 
 
 In Fig. 14, we see a section across the 
 paved floor of the southern corridor or 
 ambulatory of a quadrangle, in an excavation 
 made near "The Spring." The floor is 7 
 feet 9 inches wide, and the broken-down 
 walls now project only f of an inch above its 
 level. The field, which was in pasture, here 
 sloped from north to south, at an angle 
 of 3 40'. The nature of the ground at some 
 little distance on each side of the corridor is 
 shown in the section. It consisted of earth 
 full of stones and other debris, capped with 
 dark vegetable mould which was thicker on 
 the lower or southern than on the northern 
 side. The pavement was nearly level along 
 lines parallel to the side-walls, but had sunk 
 in the middle as much as 7f inches. 
 
 A small room at no great distance from that 
 represented in Fig. 13, had been enlarged by 
 the Eoman occupier on the southern side, by 
 an addition of 5 feet 4 inches in breadth. For 
 this purpose the southern wall of the house had 
 been pulled down, but the foundations of the 
 old wall had been left buried at a little depth
 
 216 
 
 BURIAL OF THE REMAINS CHAP. IV,
 
 CHAP. IV. OF ANCIENT BUILDINGS. 217 
 
 beneath the pavement of the enlarged room. 
 Mr. Joyce believes that this buried wall must 
 have been built before the reign of Claudius II., 
 who died 270 A.D. We see in the accom- 
 panying section, Fig. 15, that the tesselated 
 pavement has subsided to a less degree over the 
 buried wall than elsewhere ; so that a slight 
 convexity or protuberance here stretched in a 
 straight line across the room. This led to 
 a hole being dug, and the buried wall was 
 thus discovered. 
 
 We see in these three sections, and in 
 several others not given, that the old pave- 
 ments have sunk or sagged considerably. 
 Mr. Joyce formerly attributed this sinking 
 solely to the slow settling of the ground. 
 That there has been some settling is highly 
 probable, and it may be seen in Fig. 15 
 that the pavement for a width of 5 feet 
 over the southern enlargement of the 
 room, which must have been built on fresh 
 ground, has sunk a little more than on the 
 old northern side. But this sinking may 
 possibly have had no connection with the 
 enlargement of the room; for in Fig. 13 
 one half of the pavement has subsided more
 
 218 BURIAL OF THE REMAINS CHAP. IV 
 
 1
 
 CHAP. TV OF ANCIENT BUILDINGS. 219 
 
 than the other half without any assignable 
 cause. In a bricked passage to Mr. Joyce's 
 own house, laid down only about six years 
 ago, the same kind of sinking has occurred as 
 in the ancient buildings. Nevertheless it does 
 not appear probable that the whole .amount 
 of sinking can be thus accounted for. The 
 Roman builders excavated the ground to an 
 unusual depth for the foundations of their 
 walls, which were thick and solid ; it is 
 therefore hardly credible that they should 
 have been careless about the solidity of the 
 bed on which their tesselated and often 
 ornamented pavements were laid. The sink- 
 ing must, as it appears to me, be attributed 
 in chief part to the pavement having been 
 undermined by worms, which we know are 
 still at work. Even Mr. Joyce at last ad- 
 mitted that this could not have failed to have 
 produced a considerable effect. Thus also the 
 large quantity of fine mould overlying the 
 pavements can be accounted for, the presence 
 of which would otherwise be inexplicable. My 
 sons noticed that in one room in which the 
 pavement had sagged very little, there was an 
 unusually small amount of overlying mould.
 
 220 BURIAL OP THE REMAINS CHAP. IV. 
 
 As the foundations of the walls generally 
 lie at a considerable depth, they will either 
 have not subsided at all through the under- 
 mining action of worms, or they will have 
 subsided much less than the floor. This 
 latter result would follow from worms not 
 often working deep down beneath the founda- 
 tions ; but more especially from the walls not 
 yielding when penetrated by worms, whereas 
 the successively formed burrows in a mass 
 of earth, equal to one of the walls in depth 
 and thickness, would have collapsed many 
 times since the desertion of the ruins, 
 and would consequently have shrunk or 
 subsided. As the walls cannot have sunk 
 much or at all, the immediately adjoining 
 pavement from adhering to them will have 
 been prevented from subsiding; and thus 
 the present curvature of the pavement i* 
 intelligible. 
 
 The circumstance which has surprised me 
 most with respect to Silchester is that during 
 the many centuries which have elapsed since 
 the old buildings were deserted, the vegetable 
 mould has not accumulated over them to a 
 greater thickness than that here observed. In
 
 
 CHAP.V. OF ANCIENT BUILDINGS. 221 
 
 most places it is only about 9 inches in thick- 
 ness, but in some places 12 or even more 
 inches. In Fig. 11, it is given as 20 inches, 
 but this section was drawn by Mr. Joyce 
 before his attention was particularly called to 
 this subject. The land enclosed within the 
 old walls is described as sloping slightly to 
 the south ; but there are parts which, accord- 
 ing to Mr. Joyce, are nearly level, and it 
 appears that the mould is here generally 
 thicker than elsewhere. The surface slopes 
 in other parts from west to east, and Mr. Joyce 
 describes one floor as covered at the western 
 end by rubbish and mould to a thickness 
 of 28^ inches, and at the eastern end by a 
 thickness of only 11 J inches. A very slight 
 slope suffices to cause recent castings to flow 
 downwards during heavy rain, and thus much 
 earth will ultimately reach the neighbouring 
 rills and streams and be carried away. By 
 this means, the absence of very thick beds of 
 mould over these ancient rrains may, as I 
 believe, be explained. Moreover most of the 
 land here has long been ploughed, and this 
 would greatly aid the washing away of the 
 finer earth during rainy weather.
 
 222 BUEIAL OF THE BEMAINS CHAP. IV. 
 
 The nature of the beds immediately 
 beneath the vegetable mould in some of the 
 sections is rather perplexing. We see, for 
 instance, in the section of an excavation in a 
 grass meadow (Fig. 14), which sloped from 
 north to south at an angle of 3 40', that the 
 mould on the upper side is only six inches 
 and on the lower side nine inches in thick- 
 ness. But this mould lies on a mass (25 J 
 inches in thickness on the upper side) " of 
 "dark brown mould," as described by Mr. 
 Joyce, " thickly interspersed with small 
 " pebbles and bits of tiles, which present a 
 "corroded or worn appearance." The state 
 of this dark-coloured earth is like that of a 
 field which has long been ploughed, for the 
 earth thus becomes intermingled with stones 
 and fragments of all kinds which have been 
 much exposed to the weather. If during the 
 course of many centuries this grass meadow 
 and the other now cultivated fields have been 
 at times ploughed, and at other times left as 
 pasture, the nature of the ground in the above 
 section is rendered intelligible. For worms 
 will continually have brought up fine earth 
 from below, which will have been stirred
 
 CHAP. IV. OF ANCIENT BUILDINGS. 223 
 
 up by the plough whenever the land was 
 cultivated. But after a time a greater 
 thickness of fine earth will thus have been 
 accumulated than could be reached by the 
 plough; and a bed like the 25^-inch mass, 
 in Fig. 14, will have been formed beneath 
 the superficial mould, which latter will have 
 been brought to the surface within more 
 recent times, and have been well sifted by 
 the worms. 
 
 Wrosseter, Shropshire. The old Roman city 
 of Uriconium was founded in the early part 
 of the second century, if not before this date ; 
 and it was destroyed, according to Mr. 
 Wright, probably between the middle of the 
 fourth and fifth century. The inhabitants 
 were massacred, and skeletons of women 
 were found in the hypocausts. Before the 
 year 1859, the sole remnant of the city above 
 ground, was a portion of a massive wall 
 about 20 ft. in height. The surrounding 
 land undulates slightly, and has long been 
 under cultivation. It had been noticed that 
 the corn-crops ripened prematurely in certain 
 narrow lines, and that the snow remained un- 
 melted in certain places longer than in others.
 
 224 BURIAL OF THE REMAINS CHAP. IV. 
 
 These appearances led, as I was informed, to 
 extensive excavations being undertaken. The 
 foundations of many large buildings and 
 several streets have thus been exposed to view. 
 The space enclosed within the old walls is 
 an irregular oval, about 1| mile in length. 
 Many of the stones or bricks used in the 
 buildings must have been carried away ; but 
 the hypocausts, baths, and other underground 
 buildings were found tolerably perfect, being 
 filled with stones, broken tiles, rubbish and 
 soil. The old floors of various rooms were 
 covered with rubble. As I was anxious to 
 know how thick the mantle of mould and 
 rubbish was, which had so long concealed 
 these ruins, I applied to Dr. H. Johnson, who 
 had superintended the excavations ; and he, 
 with the greatest kindness, twice visited the 
 place to examine it in reference to my ques- 
 tions, and had many trenches dug in four 
 fields which had hitherto been undisturbed. 
 The results of his observations are given in 
 the following Table. He also sent me speci- 
 mens of the mould, and answered, as far as 
 he could, all my questions.
 
 CHAP. IV. OF ANCIENT BUILDINGS. 225 
 
 MEASUREMENTS BY DB. H. JOHKSON OF THE THICKNESS OF 
 THE VEGETABLE MOULD OVEB THE ROMAN BUIN8 AT 
 WBOXETER. 
 
 Trenches dug in a field called " Old Works." 
 
 Thickness 
 
 of mould in 
 
 inches. 
 
 1. At a depth of 36 inches undisturbed sand was 
 
 reached 20 
 
 2. At a depth of 33 inches concrete was reached 21 
 
 3. 9 inches concrete was reached 9 
 
 Trenches dug in a field called "Shop 
 Leasows ;" this is the highest field within the 
 old walls, and slopes down from a sub-central 
 point on all sides at about an angle of 2. 
 
 of mould in 
 inches. 
 
 4. Summit of field, trench 45 inches deep . . 40 
 
 5. Close to summit of field, trench 36 inches deep 26 
 
 6. trench 28 inches deep 28 
 
 7. Near summit of field, trench 36 inches deep 24 
 
 8. trench at. one end 39 
 inches deep ; the mould here graduated into 
 the underlying undisturbed sand, and its 
 thickness (24 inches) is somewhat arbitrary. 
 At the other end of the trench, a causeway 
 was encountered at a depth of only 7 inches, 
 and the mould was here only 7 inches thick 24 
 
 9. Trench close to the last, 28 inches in depth .. 15 
 
 10. Lower part of same field, trench 30 inches deep 15 
 
 11. trench 31 inches deep 17 
 
 12. trench 36 inches deep, 
 
 at which depth undisturbed sand was reached 28
 
 226 BURIAL OF THE REMAINS CHAP. IV. 
 
 Thickness 
 
 of mould in 
 
 inches. 
 
 13. In another part of same field, trench 9 inches 
 
 deep, stopped by concrete 9i 
 
 14. In another part of same field, trench 9 inches 
 
 deep, stopped by concrete .. .. .. 9 
 
 15. In another part of the same field, trench 24 
 
 inches deep, when sand was reached .. 16 
 
 16. In another part of same field, trench 30 inches 
 
 deep, when stones were reached ; at one end 
 of the trench mould 12 inches, at the other 
 end 14 inches thick 13 
 
 Small field between "Old Works" and 
 " Shop Leasows," I believe nearly as high as 
 the upper part of the latter field. 
 
 Thickness 
 
 of mould in 
 
 inches. 
 
 17. Trench 26 inches' deep 24 
 
 18. 10 inches deep, and then came upon a 
 causeway 10 
 
 19. Trench 34 inches deep 30 
 
 20. 31 inches deep 31 
 
 Field on the western side of the space 
 enclosed within the old walls. 
 
 Thickness 
 
 of mould in 
 
 inches. 
 
 21. Trench 28 inches deep, when undisturbed sand 
 
 was reached .. .. .. .. ..16 
 
 22. Trench 29 inches deep, when undisturbed sand 
 
 was reached .. .. .. .. .. 15 
 
 23. Trench 14 inches deep, and then came upon a 
 
 building .. .. .. .. .. 14 
 
 Dr. Johnson distinguished as mould the 
 earth which differed, more or less abruptly, in
 
 CHAP. IV. OF ANCIENT BUILDINGS. 22T 
 
 its dark colour and in its texture from the 1 
 underlying sand or rubble. In the specimen* 
 sent to me, the mould resembled that which 
 lies immediately beneath the turf in old 
 pasture-land, excepting that it often contained 
 small stones, too large to have passed through 
 the bodies of worms. But the trenches above- 
 described were dug in fields, none of which 
 were in pasture, and all had been long 
 cultivated. Bearing in mind the remarks 
 made in reference to Silchester on the effects 
 of long-continued culture, combined with the 
 action of worms in bringing up the finer 
 particles to the surface, the mould, as so- 
 designated by Dr. Johnson, seems fairly well 
 to deserve its name. Its thickness, where 
 there was no causeway, floor or walls beneath,, 
 was greater than has been elsewhere ob- 
 served, namely, in many places above 2 ft,. 
 and in one spot above 3 ft. The mould was 
 thickest on and close to the nearly level sum- 
 mit of the field called " Shop Leasows," and 
 in a small adjoining field, which, as I believe, 
 is of nearly the same height. One side of 
 the former field slopes at an angle of rather 
 above 2, and I should have expected that 
 
 R
 
 228 BUKIAL OF THE KEMAINS CHAP. IV. 
 
 the mould, from being washed down during 
 heavy rain, would have been thicker in the 
 lower than in the upper part; but this was 
 not the case in two out of the three trenches 
 here dug. 
 
 In many places, where streets ran beneath 
 the surface, or where old buildings stood, the 
 mould was only 8 inches in thickness; and 
 Dr. Johnson was surprised that in ploughing 
 the land, the ruins had never been struck by 
 the plough as far as he had heard. He thinks 
 that when the land was first cultivated the old 
 walls were perhaps intentionally pulled down, 
 and that hollow places were filled up. This 
 may have been the case; but if after the 
 desertion of the city the land was left for 
 many centuries uncultivated, worms would 
 have brought up enough fine earth to have 
 covered the ruins completely ; that is if 
 they had subsided from having been under- 
 mined. The foundations of some of the walls, 
 for instance those of the portion still stand- 
 ing about 20 feet above the ground, and 
 those of the market-place, lie at the extra- 
 ordinary depth of 14 feet; but it is highly 
 improbable that the foundations were gener-
 
 CHAP. IV. OP ANCIENT BUILDINGS. 229 
 
 ally so deep. The mortar employed in the 
 buildings must have been excellent, for it 
 is still in parts extremely hard. Wher- 
 ever walls of any height have been exposed 
 to view, they are, as Dr. Johnson believes, 
 still perpendicular. The walls with such 
 deep foundations cannot have been under- 
 mined by worms, and therefore cannot have 
 subsided, as appears to have occurred at 
 Abinger and Silchester. Hence it is very 
 difficult to account for their being now com- 
 pletely covered with earth; but how much 
 of this covering consists of vegetable mould 
 and how much of rubble I do not know. 
 The market-place, with the foundations at a 
 depth of 14 feet, was covered up, as Dr. 
 Johnson believes, by between 6 and 24 inches 
 of earth. The tops of the broken-down walls 
 of a caldarium or bath, 9 feet in depth, were 
 likewise covered up with nearly 2 feet of 
 earth. The summit of an arch, leading into 
 an ash-pit 7 feet in depth, was covered up 
 with not more than 8 inches of earth. When- 
 ever a building which has not subsided is 
 covered with earth, we must suppose, either 
 that the upper layers of stone have been at 
 
 R 2
 
 230 BUEIAL OF THE REMAINS CHAP. IV. 
 
 some time carried away by man, or that earth 
 has since been washed down during heavy 
 rain, or blown down during storms, from the 
 adjoining land ; and this would be especially 
 apt to occur where the land has long been 
 cultivated. In the above cases the adjoining 
 land is somewhat higher than the three speci- 
 fied sites, as far as I can judge by maps and 
 from information given me by Dr. Johnson. 
 If, however, a great pile of broken stones, 
 mortar, plaster, timber and ashes fell over the- 
 remains of any building, their disintegration 
 in the course of time, and the sifting action 
 of worms, would ultimately conceal the whole 
 beneath fine earth. 
 
 Conclusion. The cases given in this chapter 
 show that worms have played a considerable 
 part in the burial and concealment of several 
 Roman and other old buildings in England ; 
 but no doubt the washing down of soil from 
 the neighbouring higher lands, and the de- 
 position of dust, have together aided largely 
 in the work of concealment. Dust would be 
 apt to accumulate wherever old broken-down 
 walls projected a little above the then exist-
 
 CHAP. IV. OF ANCIENT BUILDINGS. 231 
 
 ing surface and thus afforded some shelter. 
 The floors of the old rooms, halls and passages 
 have generally sunk, partly from the settling 
 of the ground, but chiefly from having been 
 undermined by worms; and the sinking has 
 commonly been greater in the middle than 
 near the walls. The walls themselves, when- 
 ever their foundations do not lie at a great 
 depth, have been penetrated and undermined 
 by worms, and have consequently subsided. 
 The unequal subsidence thus caused, probably 
 explains the great cracks which may be seen 
 in many ancient walls, as well as their 
 inclination from the perpendicular.
 
 232 DISINTEGRATION CHAP. V. 
 
 CHAPTER Y. 
 
 THE ACTION OF WORMS IN THE DENUDATION 
 OP THE LAND. 
 
 Evidence of the amount of denudation which the land has 
 undergone Sub-aerial denudation The deposition of dust 
 Vegetable mould, its dark colour and fine texture largely due 
 to the action of worms The disintegration of rocks by the 
 humus-acids Similar acids apparently generated within the 
 bodies of worms The action of these acids facilitated by the 
 continued movement of the particles of earth A thick bed of 
 mould checks the disintegration of the underlying soil and 
 rocks. Particles of stone worn or triturated in the gizzards of 
 worms Swallowed stones serve as mill-stones The levi- 
 gated state of the castings Fragments of brick in the castings 
 over ancient buildings well rounded. The triturating power of 
 worms not quite insignificant under a geological point of view. 
 
 No one doubts that our world at one time 
 consisted of crystalline rocks, and that it is to 
 their disintegration through the action of air, 
 water, changes of temperature, rivers, waves 
 of the sea, earthquakes and volcanic outbursts, 
 that we owe our sedimentary formations. 
 These after being consolidated and sometimes
 
 CHAP. V. AND DENUDATION. 233 
 
 recrystallized, have often 'been again dis- 
 integrated. Denudation means the removal 
 of such disintegrated matter to a lower level. 
 Of the many striking results due to the 
 modern progress of geology there are hardly 
 any more striking than those which relate to 
 denudation. It was long ago seen that 
 there must have been an immense amount 
 of denudation ; but until the successive forma- 
 tions were carefully mapped and measured, 
 no one fully realised how great was the 
 amount. One of the first and most remark- 
 able memoirs ever published on this subject 
 was that by Ramsay,* who in 1846 showed 
 that in Wales from 9000 to 11,000 feet in 
 thickness of solid rock had been stripped off 
 large tracks of country. Perhaps the plainest 
 evidence of great denudation is afforded by 
 faults or cracks, which extend for many miles 
 across certain districts, with the strata on one 
 side raised even ten thousand feet above the 
 corresponding strata on the opposite side ; and 
 yet there is not a vestige of this gigantic 
 displacement visible on the surface of the 
 
 * " On the denudation of South Wales," &c., Memoirs of the 
 Geological Survey of Great Britain,' vol. i., p. 297, 134G
 
 2H4 DISINTEGRATION CHAP. V. 
 
 land. A Luge pile of rock has been planed 
 iiway on one side and not a remnant left. 
 
 Until the last twenty or thirty years, most 
 geologists thought that the waves of the sea 
 were the chief agents in the work of denuda- 
 tion ; but we may now feel sure that air and 
 rain, aided by streams and rivers, are much 
 more powerful agents, that is if we consider 
 the whole area of the land. The long lines of 
 escarpment which stretch across several parts 
 of England were formerly considered to be 
 undoubtedly ancient coast-lines ; but we now 
 know that they stand up above the general 
 surface merely from resisting air, rain and 
 frost better than the adjoining formations. 
 It has rarely been the good fortune of a 
 geologist to bring conviction to the minds of 
 his fellow- workers on a disputed point by a 
 single memoir ; but Mr. Whitaker, of the 
 Geological Survey of England, was so for- 
 tunate when, in 1867, he published his paper 
 " On sub-aerial Denudation, and on Cliffs and 
 Escarpments of the Chalk." * Before this 
 
 * 'Geological Magazine,' October and November, 18G7, vol. 
 iv. pp. 447 and 483. Copious references on the subject are given 
 in this remarkable memoir. 

 
 CHAP. Y. AND DENUDATION. 235 
 
 paper appeared, Mr. A. Tylor had adduced 
 important evidence on sub-aerial denudation, 
 by showing that the amount of matter 
 brought down by rivers must infallibly lower 
 the level of their drainage-basins by many 
 feet in no immense lapse of time. This line 
 of argument has since been followed up in the 
 most interesting manner by Archibald Geikie, 
 Croll and others, in a series of valuable 
 memoirs.* For the sake of those who have 
 never attended to this subject, a single 
 instance may be here given, namely, that of 
 the Mississippi, which is chosen because the 
 amount of sediment brought down by this 
 great river has been investigated with especial 
 care by order of the United States Govern- 
 ment. The result is, as Mr. Croll shows, that 
 the mean level of its enormous area of 
 
 * A. Tylor " On changes of the sea-level," &c., ' Philosophical 
 Mag.' (Ser. 4th) vol. v., 1853, p. 258. Archibald Geikie, 
 Transactions Geolog. Soc. of Glasgow, vol. iii., p. 153 (read March, 
 1868). Croll "On Geological Time," 'Philosophical Mag.,' 
 May, August, and November, 1868. See also Croll, * Climate 
 and Time,' 1875, Chap. XX. For some recent information on 
 the amount of sediment brought down by rivers, see ' Nature, 1 
 Sept. 23rd, 1880. Mr. T. Mellard Reade has published some 
 interesting articles on the astonishing amount of matter 
 brought down in solution by rivers. See Address, Geolog. Soc., 
 Liverpool, 1876-77.
 
 236 DISINTEGRATION CHAP. Y. 
 
 drainage must be lowered 45 1 66 of a foot 
 annually, or 1 foot in 4566 years. Con- 
 sequently, taking the best estimate of the 
 mean height of the North American continent, 
 viz. 748 feet, and looking to the future, the 
 whole of the great Mississippi basin will be 
 washed away, and " brought down to the sea- 
 " level in less than 4,500,000 years, if no 
 " elevation of the land takes place." Some 
 rivers carry down much more sediment re- 
 latively to their size, and some much less than 
 the Mississippi. 
 
 Disintegrated matter is carried away by 
 the wind as well as by running water.. 
 During volcanic outbursts much rock is 
 triturated and is thus widely dispersed; and 
 in all arid countries the wind plays an im- 
 portant part in the removal of such matter. 
 Wind-driven sand also wears down the 
 hardest rocks. I have shown* that during 
 four months of the year a large quantity of 
 dust is blown from the north-western shores 
 of Africa, and falls on the Atlantic over a 
 
 * " An account of the fine dust which often falls on Vessels ia 
 the Atlantic Ocean," Proc. Geolog. Soc. of London, June 4th,. 
 1845.
 
 CHAP. V. AND DENUDATION. 237 
 
 space of 1600 miles in latitude, and for a 
 distance of from 300 to 600 miles from the 
 coast. But dust has been seen to fall at a 
 distance of 1030 miles from the shores of 
 Africa. During a stay of three weeks at 
 St. Jago in the Cape Verde Archipelago, the 
 atmosphere was almost always hazy, and ex- 
 tremely fine dust coming from Africa was con- 
 tinually falling. In some of this dust which 
 fell in the open ocean at a distance of between 
 330 and 380 miles from the African coast, there- 
 were many particles of stone, about y^o of an 
 inch square. Nearer to the coast the water 
 has been seen to be so much discoloured by 
 the falling dust, that a sailing vessel left a 
 track behind her. In countries, like the Cape 
 Verde Archipelago, where it seldom rains 
 and there are no frosts, the solid rock never- 
 theless disintegrates ; and in conformity with 
 the views lately advanced by a distinguished 
 Belgian geologist, De Koninck, such disin- 
 tegration may be attributed in chief part to 
 the action of the carbonic and nitric acids, 
 together with the nitrates and nitrites of 
 ammonia, dissolved in the dew. 
 
 In all humid, even moderately humid,
 
 238 DISINTEGRATION CHAP. V. 
 
 countries, worms aid in the work of denuda- 
 tion in several ways. The vegetable mould 
 which covers, as with a mantle, the surface 
 of the land, has all passed many times 
 through their bodies. Mould differs in ap- 
 pearance from the subsoil only in its dark 
 colour, and in the absence of fragments or 
 particles of stone (when such are present in 
 the subsoil), larger than those which can pass 
 through the alimentary canal of a worm. 
 This sifting of the soil is aided, as has already 
 been remarked, by burrowing animals of 
 many kinds, especially by ants. In countries 
 where the summer is long and dry, the 
 mould in protected places must be largely 
 increased by dust blown from other and more 
 exposed places. For instance, the quantity 
 of dust sometimes blown over the plains of 
 La Plata, where there are no solid rocks, is 
 so great, that during the " gran seco," 1827 
 to 1830, the appearance of the land, which 
 is here unenclosed, was so completely changed 
 that the inhabitants could not recognise the 
 limits of their own estates, and endless law- 
 suits arose. Immense quantities of dust are 
 likewise blown about in Egypt and in the
 
 CHAP. V. AND DENUDATION. 23 
 
 south of France. In China, as Bichthofcn 
 maintains, beds appearing like fine sediment, 
 several hundred feet in thickness and extend- 
 ing over an enormous area, owe their origin 
 to dust blown from the high lands of central 
 Asia.* In humid countries like Great 
 Britain, as long as the land remains in its 
 natural state clothed with vegetation, the 
 mould in any one place can hardly be much 
 increased by dust ; but in its present con- 
 dition, the fields near high roads, where there 
 is much traffic, must receive a considerable 
 amount of dust, and when fields are harrowed 
 during dry and windy weather, clouds of dust 
 may be seen to be blown away. But in all 
 these cases the surface-soil is merely trans- 
 ported from one place to another. The dust 
 which falls so thickly within our houses con- 
 
 * For La Plata, see my ' Journal of Researches,' during the 
 voyage of the Beagle, 1845, p. 133. Elie de Beaumont has 
 given (' Lecons de Geolog. pratique,' torn. 1. 1845, p. 183) an 
 excellent account of the enormous quantity of dust which is 
 transported in some countries. I cannot but think that Mr. 
 Proctor has somewhat exaggerated (' Pleasant Ways in Science,' 
 1879, p. 379) the agency of dust in a humid country like Great 
 Britain. James Geikie has given (' Prehistoric Europe,' 1880, 
 p. 165) a full abstract of Richthofen's views, which, however, 
 he disputes,
 
 "240 DISINTEGRATION CHAP. V. 
 
 sists largely of organic matter, and if spread 
 over the land would in time decay and dis- 
 appear almost entirely. It appears, however, 
 from recent observations on the snow-fields 
 of the Arctic regions, that some little meteoric 
 dust of extra mundane origin is continually 
 falling. 
 
 The dark colour of ordinary mould is 
 obviously due to the presence of decaying 
 organic matter, which, however, is present in 
 but small quantities. The loss of weight 
 which mould suffers when heated to redness 
 seems to be in large part due to water in com- 
 bination being dispelled. In one sample of 
 fertile mould the amount of organic matter 
 was ascertained to be only 1*76 per cent. ; in 
 some artificially prepared soil it was as much 
 as 5' 5 per cent., and in the famous black soil of 
 Russia from 5 to even 12 per cent.* In leaf- 
 mould formed exclusively by the decay of 
 leaves the amount is much greater, and in 
 peat the carbon alone sometimes amounts to 
 
 * These statements are taken from Hensen in 'Zeitschrift 
 fur wissenschaft. Zoologie' Bd. xxviii., 1877, p. 360. Those 
 with respect to peat are taken from Mr. A. A. Julien in ' Proc. 
 American Assoc. Science,' 1879 p. 314.
 
 CHAP. V. AND DENUDATION. 241 
 
 64 per cent. ; but with these latter cases we 
 are not here concerned. The carbon in the 
 soil tends gradually to oxidise and to dis- 
 appear, except where water accumulates and 
 the climate is cool ; * so that in the oldest 
 pasture-land there is no great excess of 
 organic matter, notwithstanding the con- 
 tinued decay of the roots and the underground 
 stems of plants, and the occasional addition 
 of manure. The disappearance of the organic 
 matter from mould is probably much aided 
 by its being brought again and again to the 
 surface in the castings of worms. 
 
 Worms, on the other hand, add largely to 
 the organic matter in the soil by the astonish- 
 ing number of half-decayed leaves which 
 they draw into their burrows to a depth of 2 
 or 3 inches. They do this chiefly for obtain- 
 ing food, but partly for closing the mouths 
 of their burrows and for lining the upper 
 part. The leaves which they consume are 
 moistened, torn into small shreds, partially 
 digested, and intimately commingled with 
 
 * I have given some facts on the climate necessary or favour* 
 able for the formation of peat, in my * Journal of Researches,' 
 1845, p. 287.
 
 242 DISINTEGRATION CHAP. Y. 
 
 earth ; and it is this process which gives to 
 vegetable mould its uniform dark tint. It is 
 known that various kinds of acids are gene- 
 rated by the decay of vegetable matter ; and 
 from the contents of the intestines of worms and 
 from their castings being acid, it seems pro- 
 bable that the process of digestion induces an 
 analogous chemical change in the swallowed, 
 triturated, and half-decayed leaves. The large 
 quantity of carbonate of lime secreted by the 
 calciferous glands apparently serves to neutra- 
 lise the acids thus generated ; for the digestive 
 fluid of worms will not act unless it be alkaline. 
 As the contents of the upper part of their in- 
 testines are acid, the acidity can hardly be due 
 to the presence of uric acid. We may there- 
 fore conclude that the acids in the alimentary 
 canal of worms are formed during the diges- 
 tive process; and that probably they are 
 nearly of the same nature as those in ordinary 
 mould or humus. The latter are well known to 
 have the power of de-oxidising or dissolving 
 per-oxide of iron, as may be seen wherever 
 peat overlies red sand, or where a rotten root 
 penetrates such sand. Now I kept some 
 worms in a pot filled with very fine reddish
 
 HAP. V. AND DENUDATION. 243 
 
 sand, consisting of minute particles of silex 
 coated with the red oxide of iron ; and the 
 burrows, which the worms made through this 
 sand, were lined or coated in the usual manner 
 with their castings, formed of the sand mingled 
 with their intestinal secretions and the refuse 
 of the digested leaves; and this sand had 
 almost wholly lost its red colour. When 
 small portions of it were placed under the 
 microscope, most of the grains were seen to 
 be transparent and colourless, owing to the 
 dissolution of the oxide ; whilst almost all the 
 grains taken from other parts of the pot were 
 coated with the oxide. Acetic acid produced 
 hardly any effect on this sand ; and even 
 hydrochloric, nitric and sulphuric acids, 
 diluted as in the Pharmacopoeia, produced 
 less effect than did the acids in the intestines 
 of the worms. 
 
 Mr. A. A. Julien has lately collected all 
 the extant information about the acids gen- 
 erated in humus, which, according to some 
 chemists, amount to more than a dozen 
 different kinds. These acids, as well as their 
 acid salts (i.e., in combination with potash, 
 soda, and ammonia), act energetically on 
 
 8
 
 244 DISINTEGRATION CHAP. V, 
 
 carbonate of lime and on the oxides of iron. 
 It is also known that some of these acids,. 
 which were called long ago by Thenard azo- 
 humic, are enabled to dissolve colloid silica in 
 proportion to the nitrogen which they contain.* 
 In the formation of these latter acids worms 
 probably afford some aid, for Dr. H. Johnson 
 informs me that by Nessler's test he found, 
 O'OIS per cent, of ammonia in their castings. 
 It may be here added that I have recently 
 been informed by Dr. Grilbert "that several 
 " square yards on his lawn were swept clean, 
 " and after two or three weeks all the worin- 
 " castings on the space were collected and 
 '* dried. These were found to contain 0'35 
 *' of nitrogen. This is from two to three times 
 " as much as we find in our ordinary arable 
 " surface-soil ; more than in our ordinary 
 " pasture surface-soil ; but less than in rich 
 " kitchen-garden mould. Supposing a quantity 
 "of castings equal to 10 tons in the dry 
 
 * A. A. Julieu " On the Geological action of the Humus-acids," 
 'Proc. American Assoc. Science,' vol. xxviii., 1879, p. 311. 
 Also on " Chemical erosion on Mountain Summits ;" ' New York 
 Academy of Sciences,' Oct. 14, 1878, as quoted in the ' American 
 Naturalist.' See also, on this subject, S. W. Johnson, ' How 
 Crops Feed,' 1870, p. 138.
 
 CHAP. V. AND DENUDATION. 245 
 
 " state were annually deposited on an acre, 
 " this would represent a manuring of 78 Ibs. 
 " of nitrogen per acre per annum ; and this 
 "is very much more than the amount of 
 " nitrogen in the annual yield of hay per 
 "acre, if raised without any nitrogenous 
 " manure. Obviously, so far as the nitrogen 
 "in the castings is derived from surface- 
 " growth or from surface-soil, it is not a gain 
 "to the latter; but so far as it is derived from 
 " below, it is a gain." 
 
 The several humus-acids, which appear, as 
 we have just seen, to be generated within the 
 bodies of worms during the digestive process, 
 and their acid salts, play a highly important 
 part, according to the recent observations of 
 Mr. Julien, in the disintegration of various 
 kinds of rocks. It has long been known that 
 the carbonic acid, and no doubt nitric and 
 nitrous acids, which are present in rain-water, 
 act in like manner. There is, also, a great 
 excess of carbonic acid in all soils, especially 
 in rich soils, and this is dissolved by the water 
 in the ground. The living roots of plants, 
 moreover, as Sachs and others have shown, 
 quickly corrode and leave their impressions 
 
 s 2
 
 '246 DISINTEGKATION CHAP. V. 
 
 on polished slabs of marble, dolomite and 
 phosphate of lime. They will attack even 
 basalt and sandstone.* But we are not here 
 concerned with agencies which are wholly 
 independent of the action of worms. 
 
 The combination of any acid with a base 
 is much facilitated by agitation, as fresh 
 surfaces are thus continually brought into 
 contact. This will be thoroughly effected 
 with the particles of stone and earth in the 
 intestines of worms, during the digestive pro- 
 cess ; and it should be remembered that the 
 entire mass of the mould over every field, 
 passes, in the course of a few years, through 
 their alimentary canals. Moreover as the old 
 'burrows slowly collapse, and as fresh castings 
 are continually brought to the surface, the 
 whole superficial layer of mould slowly re- 
 solves or circulates; and the friction of the 
 particles one with another will rub off the 
 finest films of disintegrated matter as soon as 
 they are formed. Through these several 
 means, minute fragments of rocks of many 
 
 kinds and mere particles in the soil will be 
 
 
 
 * See, for references on this subject, S. W. Johnson, ' How 
 'Crops Feed, 1 1870, p. 326.
 
 CHAP. V. AND DENUDATION. 247' 
 
 continually exposed to chemical decomposi- 
 tion ; and thus the amount of soil will tend 
 to increase. 
 
 As worms line their burrows with their 
 castings, and as the burrows penetrate to a- 
 depth of 5 or G, or even more feet, some- 
 small amount of the humus-acids will be- 
 carried far down, and will there act on the- 
 underlying rocks and fragments of rock, 
 Thus the thickness of the soil, if none be re- 
 moved from the surface, will steadily though 
 slowly tend to increase ; but the accumulation 
 will after a time delay the disintegration of" 
 the underlying rocks and of the more deeply 
 seated particles. For the humus-acids which 
 are generated chiefly in the upper layer of 
 vegetable mould, are extremely unstable com- 
 pounds, and are liable to decomposition before 
 they reach any considerable depth.* A thick" 
 bed of overlying soil will also check the: 
 downward extension of great fluctuations of 
 temperature, and in cold countries will check 
 the powerful action of frost. The free access 
 of air will likewise be excluded. From these- 
 
 * This statement is taken from Mr. Julien, ' Proc. American 
 Assoc. Science,' vol. xxviii., 1879, p. 330.
 
 248 DISINTEGRATION CHAP. V. 
 
 several causes disintegration would be almost 
 arrested, if the overlying mould were to 
 increase much in thickness, owing to none or 
 little being removed from the surface.* In 
 my own immediate neighbourhood we have a 
 curious proof how effectually a few feet of 
 clay checks some change which goes on in 
 flints, lying freely exposed; for the large 
 ones which have lain for some time on the 
 surface of ploughed fields cannot be used for 
 building ; they will not cleave properly and 
 are said by the workmen to be rotten, f It is 
 therefore necessary to obtain flints for build- 
 ing purposes from the bed of red clay over- 
 
 * The preservative power of a layer of mould and turf is often 
 /hown by the perfect state of the glacial scratches on rocks when 
 first uncovered. Mr. J. Geikie maintains, in his last very inter- 
 esting work (' Prehistoric Europe,' 1881), that the more perfect 
 scratches are probably due to the last access of cold and increase 
 of ice, during the long-continued, intermittent glacial period. 
 
 f Many geologists have felt much surprise at the complete 
 disappearance of flints over wide and nearly level areas, from 
 which the chalk has been removed by subaerial denudation. 
 But the surface o every flint is coated by an opaque modified 
 layer, which will just yield to a steel point, whilst the freshly- 
 fractured, translucent surface will not thus yield. The re- 
 moval by atmospheric agencies of the outer modified surfaces 
 of freely exposed flints, though no doubt excessively slow, to- 
 gether with the modification travelling inwards, will, as may be 
 suspected, ultimately lead to their complete disintegration, not- 
 withstanding that they appear to be so extremely durable.
 
 CHAP. Y AND DENUDATION. 249 
 
 jying the chalk (the residue of its dissolution 
 "by rain-water) or from the chalk itself. 
 
 Not only do worms aid indirectly in the 
 chemical disintegration of rocks, but there is 
 good reason to believe that they likewise act 
 in a direct and mechanical manner on the 
 smaller particles. All the species which 
 swallow earth are furnished with gizzards; 
 and these are lined with so thick a chitinous 
 membrane, that Perrier speaks of it,* as " une 
 veritable armature." The gizzard is sur- 
 rounded by powerful transverse muscles, 
 which, according to Claparede, are about ten 
 times as thick as the longitudinal ones ; and 
 Perrier saw them contracting energetically. 
 Worms belonging to one genus, Digaster, 
 have two distinct but quite similar gizzards; 
 and in another genus, Moniligaster, the 
 second gizzard consists of four pouches, one 
 succeeding the other, so that it may almost 
 be said to have five gizzards.:]" In the same 
 manner as gallinaceous and struthious birds 
 swallow stones to aid in the trituration of 
 
 * Archives de Zoolog. expeVtom. iii. 1874, p. 409. 
 t ' Nouvelles Archives du Muse'um,' torn, \viii. 1872, p. 95, 
 131.'
 
 250 DISINTEGRATION CHAP. V. 
 
 their food, so it appears to be with terricolous 
 worms. The gizzards of thirty-eight of our 
 common worms were opened, and in twenty- 
 five of them small stones or grains of sand, 
 sometimes together with the hard calcareous 
 concretions formed within the anterior cal- 
 ciferous glands, were found, and in two others- 
 concretions alone. In the gizzards of the 
 remaining worms there were no stones; but 
 some of these were not real exceptions, as 
 the gizzards were opened late in the autumn, 
 when the worms had ceased to feed and their 
 gizzards were quite empty.* 
 
 When worms make their burrows through 
 earth abounding with little stones, no doubt 
 many will be unavoidably swallowed ; but 
 it must not be supposed that this fact 
 accounts for the frequency with which stones 
 and sand are found in their gizzards. For 
 beads of glass and fragments of brick and of 
 hard tiles were scattered over the surface 
 of the earth, in pots in which worms were 
 kept and had already made their burrows; 
 
 * Morren, In speaking of the earth in the alimentary canals of 
 worms, says, " praesepfc cum lapillis commixtam vidi : " ' De 
 Lumbrici terrestris Hist. Nat.' &c., 1829, p. 16.
 
 CHAP. V. AND DENUDATION. 251 
 
 and very many of these beads and fragments 
 were picked up and swallowed by the worms, 
 for they were found in their castings, intes- 
 tines, and gizzards. They even swallowed 
 the coarse red dust, formed by the pounding 
 of the tiles. Nor can it be supposed that 
 they mistook the beads and fragments for 
 food ; for we have seen that their taste is 
 delicate enough to distinguish between dif- 
 ferent kinds of leaves. It is therefore 
 manifest that they swallow hard objects, 
 such as bits of stone, beads of glass and 
 angular fragments of bricks or tiles for 
 some special purpose ; and it can hardly be 
 doubted that this is to aid their gizzards 
 in crushing and grinding the earth, which 
 they so largely consume. That such hard 
 objects are not necessary for crushing 
 leaves, may be inferred from the fact 
 that certain species, which live in mud 
 or water and feed on dead or living 
 vegetable matter, but which do not swallow 
 earth, are not provided with gizzards,* and 
 therefore cannot have the power of utilising 
 stones. 
 
 * Perrier, 'Archives de Zoolog. exper.' torn. iii. 1874, p. 419.
 
 252 DISINTEGRATION CHAP. V. 
 
 During the grinding process, the particles 
 of earth must be rubbed against one another, 
 and between the stones and the tough 
 lining membrane of the gizzard. The softer 
 particles will thus suffer some attrition, and 
 will perhaps even be crushed. This con- 
 clusion is supported by the appearance of 
 freshly ejected castings, for these often re- 
 minded me of the appearance of paint which 
 has just been ground by a workman between 
 two flat stones. Morren remarks that the 
 intestinal canal is " impleta tenuissima terra, 
 veluti in pulverem redacta." * Perrier also 
 .speaks of " 1'e'tat de pate excessivement fine a 
 laquelle est reduite la terre qu'ils rejettent," 
 
 As the amount of trituration which the 
 particles of earth undergo in the gizzards 
 of worms possesses some interest (as we 
 shall hereafter see), I endeavoured to obtain 
 evidence on this head by carefully examining 
 many of the fragments which had passed 
 through their alimentary canals. "With 
 "worms living in a state of nature, it is of 
 
 * Morren, ' De Lumbrici terrestris Hist. Nat.' &c., p. 16. 
 f ' Archives de Zoolog. expdr.' torn. iii. 1874, p. 418.
 
 CHAP. V. AND DENUDATION. 253 
 
 course impossible to know how much the 
 fragments may have been worn before they 
 were swallowed. It is, however, clear that 
 worms do not habitually select already 
 rounded particles, for sharply angular bits 
 of flint and of other hard rocks were often 
 found in their gizzards or intestines. On 
 three occasions sharp spines from the stems 
 of rose-bushes were thus found. "Worms kept 
 in confinement repeatedly swallowed angular 
 fragments of hard tile, coal, cinders, and even 
 the sharpest fragments of glass. Gallinaceous 
 and struthious birds retain the same stones 
 in their gizzards for a long time, which thus 
 become well rounded ; but this does not 
 appear to be the case with worms, judging 
 from the large number of the fragments of 
 tiles, glass beads, stones, &c., commonly found 
 in their castings and intestines. So that 
 unless the same fragments were to pass re- 
 peatedly through their gizzards, visible signs 
 of attrition in the fragments could hardly be 
 expected, except perhaps in the case of very 
 :soft stones. 
 
 I will now give such evidence of attrition 
 as I have been able to collect. In the
 
 254 DISINTEGKATION CHAP. Y, 
 
 gizzards of some worms dug out of a thin bed 
 of mould over the chalk, there were many well- 
 rounded small fragments of chalk, and two 
 fragments of the shells of a land-mollusc (as 
 ascertained by their microscopical structure), 
 which latter were not only rounded but 
 somewhat polished. The calcareous concre- 
 tions formed in the calciferous glands, which 
 are often found in their gizzards, intestines, 
 and occasionally in their castings, when of 
 large size, sometimes appeared to have been 
 rounded ; but with all calcareous bodies 
 the rounded appearance may be partly or 
 wholly due to their corrosion by carbonic 
 acid and the humus-acids. In the gizzards 
 of several worms collected in my kitchen 
 garden near a hothouse, eight little frag- 
 ments of cinders were found, and of these, 
 six appeared more or less rounded, as were 
 two bits of brick ; but some other bits were 
 not at all rounded. A farm-road near 
 Abinger Hall had been covered seven years 
 before with brick-rubbish to the depth of 
 about 6 inches ; turf had grown over this 
 rubbish on both sides of the road for a 
 width of 18 inches, and on this turf there
 
 HAP. V. AND DENUDATION. 255 
 
 were innumerable castings. Some of them 
 were coloured of a uniform red owing to 
 the presence of much brick-dust, and they 
 contained many particles of brick and of 
 hard mortar from 1 to 3 mm. in diameter, 
 most of which were plainly rounded; but 
 all these particles may have been rounded 
 before they were protected by the turf and 
 were swallowed, like those on the bare parts 
 of the road which were much worn. A hole 
 in a pasture-field had been filled up with 
 brick-rubbish at the same time, viz., seven 
 years ago, and was now covered with turf; 
 and here the castings contained very many 
 particles of brick, all more or less rounded ; 
 .and this brick-rubbish, after being shot into 
 the hole, could not have undergone any 
 attrition. Again, old bricks very little 
 broken, together with fragments of mortar, 
 were laid down to form walks, and were 
 then covered with from 4 to 6 inches of 
 gravel; six little fragments of brick were 
 extracted from castings collected on these 
 walks, three of which were plainly worn. 
 There were also very many particles of hard 
 mortar, about half of which were well
 
 256 DISINTEGRATION CHAP. V. 
 
 rounded; and it is not credible that these 
 could have suffered so much corrosion from 
 the action of carbonic acid in the course of 
 only seven years. 
 
 Much better evidence of the attrition of 
 hard objects in the gizzards of worms, is 
 afforded by the state of the small fragments 
 of tiles or bricks, and of concrete in the 
 castings thrown up where ancient buildings 
 once stood. As all the mould covering a 
 field passes every few years through the 
 bodies of worms, the same small fragments 
 will probably be swallowed and brought to 
 the surface many times in the course of cen- 
 turies. It should be premised that in the 
 several following cases, the finer matter was 
 first washed away from the castings, and 
 then all the particles of bricks, tiles and con- 
 crete were collected without any selection, and 
 were afterwards examined. Now in the cast- 
 ings ejected between the tesserae on one of the 
 buried floors of the Roman villa at Abinger, 
 there were many particles (from J to 2 mm. 
 in diameter) of tiles and concrete, which it 
 was impossible to look at with the naked eye 
 or through a strong lens, and doubt for a
 
 CHAP. V. AND DENUDATION. 257 
 
 moment that they had almost all undergone 
 much attrition. I speak thus after haying- 
 examined small water-worn pebbles, formed 
 from Roman bricks, which M. Henri de 
 Saussure had the kindness to send me, and 
 which he had extracted from sand and gravel 
 beds, deposited on the shores of the Lake of 
 Geneva, at a former period when the water 
 stood at about two metres above its present 
 level. The smallest of these water-worn 
 pebbles of brick from Geneva resembled 
 closely many of those extracted from the 
 gizzards of worms, but the larger ones were 
 somewhat smoother. 
 
 Four castings found on the recently un- 
 covered, tesselated floor of the great room in 
 the Roman villa at Brading, contained many 
 particles of tile or brick, of mortar, and of 
 hard white cement ; and the majority of these 
 appeared plainly worn. The particles of 
 mortar, however, seemed to have suffered 
 more corrosion than attrition, for grains .of 
 silex often projected from their surfaces. 
 Castings from within the nave of Beaulieu 
 Abbey, which was destroyed by Henry VIII.,. 
 were collected from a level expanse of turf,,
 
 258 DISINTEGBATION CHAP. V. 
 
 overlying the buried tesselated pavement, 
 through which worm-burrows passed ; and 
 these castings contained innumerable particles 
 of tiles and bricks, of concrete and cement, 
 the majority of which had manifestly under- 
 gone some or much attrition. There were 
 also many minute flakes of a micaceous slate, 
 the points of which were rounded. If the above 
 supposition, that in all these cases the same 
 minute fragments have passed several times 
 through the gizzards of worms, be rejected, 
 notwithstanding its inherent probability, we 
 must then assume that in all the above cases 
 the many rounded fragments found in the 
 castings had all accidentally undergone much 
 attrition before they were swallowed ; and 
 this is highly improbable. 
 
 On the other hand it must be stated that 
 fragments of ornamental tiles, somewhat 
 harder than common tiles or bricks, which 
 had been swallowed only once by worms kept 
 in confinement, were with the doubtful ex- 
 ception of one or two of the smallest grains, 
 not at all rounded. Nevertheless some of 
 them appeared a little worn, though not 
 rounded. Notwithstanding these cases, if we
 
 CHAP. V. AND DENUDATION. 259 
 
 consider the evidence above given, there can 
 be little 'doubt that the fragments, which serve 
 as millstones in the gizzards of worms, suffer, 
 when of a not very hard texture, some amount 
 of attrition; and that the smaller particles in 
 the earth, which is habitually swallowed in 
 such astonishingly large quantities by worms, 
 are ground together and are thus levigated. 
 If this, be the case, the " terra tenuissima," 
 the "pate excessivemerit fine," of which the 
 castings largely consist, is in part due to the 
 mechanical action of the gizzard ; * and this 
 fine matter, as we shall see in the next chapter, 
 is that which is chiefly washed away from the 
 innumerable castings on every field during 
 each heavy shower of rain. If the softer stones 
 yield at all, the harder ones will suffer 
 some slight amount of wear and tear. 
 
 The trituration of small particles of stone 
 
 * This conclusion reminds me of the vast amount of extremely 
 fine chalky mud which is found within the lagoons of many 
 atolls, where the sea is tranquil and waves cannot triturate the 
 blocks of coral. This mud must, as I believe (' The Structure and 
 Distribution of Coral-Reefs,' 2nd edit. 1874, p. 19), be attributed 
 to the innumerable annelids and other animals which burrow 
 into the dead coral, and to the fishes, Holothurians, &c., which 
 browse.on the living corals. 
 
 T
 
 260 DISINTEGRATION CHAP. V. 
 
 in the gizzards of worms is of more import- 
 ance under a geological point of view than 
 may at fir.<t appear to be the case; for Mr. 
 Sorby has clearly shown that the ordinary 
 means of disintegration, namely, running 
 water and the waves of the sea, act with 
 less and less power on fragments of rock the 
 smaller they are. " Hence," as he remarks, 
 "even making no allowance for the extra 
 " buoying up of very minute particles by a 
 " current of water, depending on surface 
 " cohesion, the effects of wearing on the form 
 *' of the grains must vary directly as their 
 " diameter or thereabouts. If so, a grain y 1 ^ 
 " of an inch in diameter would be worn ten 
 " times as much as one y^-g- of an inch in 
 " diameter, and at least a hundred times as 
 "much as one -y^Vff of an inch in diameter. 
 ** Perhaps, then, we may conclude that a 
 "grain y 1 ^ of an inch in diameter would be 
 " worn as much or more in drifting a mile as 
 " a grain yoVg- of an inch in being drifted 
 " 100 miles. On the same principle a pebble 
 "one inch in diameter would be worn re- 
 *' latively more by being drifted only a few
 
 CHAP. V. AND DENUDATION. 261 
 
 " hundred yards." * Nor should we forget, in 
 considering the power which worms exert in 
 triturating particles of" rock, that there is good 
 evidence that on each acre of land, which is 
 sufficiently damp and not too sandy, gravelly 
 or rocky for worms to inhabit, a weight of 
 more than ten tons of earth annually passes 
 through their bodies and is brought to the 
 surface. The result for a country of the size 
 of Great Britain, within a period not very 
 long in a geological sense, such as a million 
 years, cannot be insignificant ; for the ten tons 
 of earth has to be multiplied first by the above 
 number of years, and then by the number of 
 acres fully stocked with worms; and in 
 England, together with Scotland, the land 
 which is cultivated and is well fitted for these 
 animals, has been estimated at above 32 
 million acres. The product is 320 million 
 million tons of earth. 
 
 * Anniversary Address : ' The Quarterly Journal of the 
 Geological Soc.' May 1880, p. 59. 
 
 T 2
 
 262 DENUDATION OF THE LAND CHAP. VI. 
 
 CHAPTER VI. 
 
 THE DENUDATION OF THE LAND Continued, 
 
 Denudation aided by recently ejected castings flowing down 
 inclined grass-covered surfaces The amount of earth which 
 annually flows downwards The effect of tropical rain on 
 worm castings The finest particles of earth washed com- 
 pletely away from castings The disintegration of dried cast- 
 ings into pellets, and their rolling down inclined surfaces 
 The formation of little ledges on hill-sides, in part due to the 
 accumulation of disintegrated castings Castings blown to 
 leeward over level land An attempt to estimate the amount 
 thus blown The degradation of ancient encampments and 
 tumuli The preservation of the crowns and furrows on land 
 anciently ploughed The formation and amount of mould 
 over the Chalk formation. 
 
 WE are now prepared to consider the more 
 direct part which worms take in the denuda- 
 tion of the land. When reflecting on sub- 
 aerial denudation, it formerly appeared to 
 me, as it has to others, that a nearly level or 
 very gently inclined surface, covered with 
 turf, could suffer no loss during even a long 
 lapse of time. It may, however, be urged 
 that at long intervals, debacles of rain or
 
 CHAP. VI, AIDED BY WORMS. 263 
 
 water-spouts would remove all the mould 
 from a i ver y gentle slope ; but when ex- 
 amining the steep, turf-covered slopes in 
 Glen Roy, I was struck with the fact how 
 rarely any such event could have happened 
 since the Glacial period, as was plain from the, 
 well-preserved state of the three successive 
 <4 roads" or lake-margins. But the difficulty 
 in believing that earth in any .appreciable 
 quantity can be removed from a gently in- 
 clined surface, covered with vegetation and 
 matted with roots, is removed through the. 
 agency of worms. For the many castings 
 which are thrown up during rain, and those 
 thrown up some little time before heavy rain, 
 flow for a short distance down an inclined 
 surface. Moreover much of the finest levi- 
 gated earth is washed completely away from 
 the castings. During dry weather castings 
 often disintegrate into small rounded pellets, 
 and these from their weight often roll down 
 any slope. This is more especially apt to 
 occur when they are started by the wind, 
 and probably when started by the touch of an 
 animal, however small. We shall also see 
 that a strong wind blows all the castings,
 
 264 DENUDATION OF THE LAND CHAP. VI. 
 
 even on a level field, to leeward, whilst they 
 are soft; and in like manner the pellets 
 when they are dry. If the wind blows in 
 nearly the direction of an inclined surface, 
 the flowing down of the castings is much 
 aided. 
 
 The observations on which these several 
 statements are founded must now be given in 
 some detail. Castings when first ejected are 
 viscid and soft ; during rain, at which time 
 worms apparently prefer to eject them, they 
 are still softer ; so that I have sometimes 
 thought that worms must swallow much 
 water at such times. However this may 
 be, rain, even when not very heavy, if 
 long continued, renders recently-ejected 
 castings semi-fluid ; and on level ground 
 they then spread out into thin, circular, flat 
 discs, exactly as would so much honey or 
 very soft mortar, with all traces of their 
 vermiform structure lost. This latter fact 
 was sometimes made evident, when a worm 
 had subsequently bored through a flat circular 
 disc of this kind, and heaped up a fresh 
 vermiform mass in the centre. These flat 
 subsided discs have been repeatedly seen b^ f
 
 CHAP. VI. AIDED BY WORMS. 265 
 
 me after heavy rain, in many places on land 
 of all kinds. 
 
 On the flowing of wet castings, and tlie 
 rolling of dry disintegrated castings down 
 inclined surfaces. When castings are ejected 
 on an inclined surface during or shortly 
 before heavy rain, they cannot fail to flow a 
 little down the slope. Thus, on some steep 
 slopes in Knole Park, which were covered 
 with coarse grass and had apparently existed 
 in this state from time immemorial, I found 
 (Oct. 22, 1872) after several wet days that 
 almost all the many castings were con- 
 siderably elongated in the line of the slope ; 
 and that they now consisted of smooth, only 
 slightly conical masses. Whenever the 
 mouths of the burrows could be found from 
 which the earth had been ejected, there was 
 more earth below than above them. After 
 some heavy storms of rain (Jan. 25, 1872) 
 two rather steeply inclined fields near Down, 
 which had formerly been ploughed and were 
 now rather sparsely clothed with poor grass, 
 were visited, and many castings extended 
 down the slopes for a length of 5 inches, 
 which was twice or thrice the usual diameter
 
 26ft DENUDATION OP THE LAND CHAP. Vl 
 
 of the castings thrown up on the level parts 
 of these same fields. On some fine grassy 
 slopes in Holwood Park, inclined at angles 
 between 8 and 11 30' with the horizon, 
 where the surface apparently had never been 
 disturbed by the hand of man, castings 
 abounded in extraordinary numbers : and a 
 space 16 inches in length transversely to the 
 slope and 6 inches in the line of the slope, 
 was completely coated, between the blades of 
 grass, with a uniform sheet of confluent and 
 subsided castings. Here also in many places 
 the castings had flowed down the slope, and 
 now formed smooth narrow patches of earth, 
 6, 7, and 7J inches in length. Some of these 
 consisted of two castings, one above the other, 
 which had become so completely confluent 
 that they could hardly be distinguished. On 
 my lawn, clothed with very fine grass, most 
 of the castings are black, but some are 
 yellowish from earth having been brought 
 up from a greater depth than usual, and the 
 flowing-down of these yellow castings after 
 heavy rain, could be clearly seen where the 
 slope was 5 ; and where it was less than 1 
 some evidence of their flowing down could
 
 CHAP. VI. AIDED BY WORMS. 267 
 
 still be detected. On another occasion, after 
 rain which was never heavy, but which lasted 
 for 18 hours, all the castings on this same 
 gently inclined lawn had lost their vermiform 
 structure ; and they had flowed, so that fully 
 two-thirds of the ejected earth lay below the 
 mouths of the burrows. 
 
 These observations led me to make others 
 with more care. Eight castings were found on 
 my lawn, where the grass-blades are fine and 
 close together, and three others on a field with 
 coarse grass. The inclination of the surface at 
 the eleven places where these castings were 
 collected varied between 4 30' and 17 30' ; 
 the mean of the eleven inclinations being 
 9 26'. The length of the castings in the 
 direction of the slope was first measured with 
 as much accuracy as their irregularities would 
 permit. It was found possible to make these 
 measurements within about ^ of an inch, but 
 one of the castings was too irregular to admit 
 of measurement. The average length in the 
 direction of the slope of the remaining ten 
 castings was 2*03 inches. The castings were 
 then divided with a knife into two parts along 
 a horizontal line passing through the mouth
 
 268 DENUDATION OF THE LAND CHAP. VI. 
 
 of the burrow, which was discovered by slicing 
 off the turf; and all the ejected earth was 
 separately collected, namely, the part above 
 the hole and the part below. Afterwards 
 these two parts were weighed. In every 
 case there was much more earth below than 
 above ; the mean weight of that above being 
 103 grains, and of that below 205 grains ; so 
 that the latter was very nearly double the 
 former. As on level ground castings are 
 commonly thrown up almost equally round 
 the mouths of the burrows, this difference in 
 weight indicates the amount of ejected earth 
 which had flowed down the slope. But very 
 many more observations would be requisite 
 to arrive at any general result ; for the 
 nature of the vegetation and other accidental 
 circumstances, such as the heaviness of the 
 rain, the direction and force of the wind, &c., 
 appear to be more important in determining 
 the quantity of the earth which flows down a 
 slope than its angle. Thus with four castings 
 on my lawn (included in the above eleven) 
 where the mean slope was 7 19', the difference 
 in the amount of earth above and below the 
 burrows was greater than with three other
 
 CHAP. VI. AIDED BY WORMS. 269 
 
 castings on the- same lawn where the mean 
 slope was 12 5'. 
 
 We may, however, take the above eleven 
 cases, which are accurate as far as they go, 
 and calculate the weight of the ejected earth 
 which annually flows down a slope having a 
 mean inclination of 9 26'. This was done 
 by my son George. It has been shown 
 that almost exactly two-thirds of the ejected 
 earth is found below the mouth of the 
 burrow and one-third above it. Now if the 
 two-thirds which is below the hole be divided 
 into two equal parts, the upper half of this 
 two-thirds exactly counterbalances the one- 
 third which is above the hole, so that as far 
 as regards the one-third above and the upper 
 half of the two-thirds below, there is no flow 
 of earth down the hill-side. The earth con- 
 stituting the lower half of the two-thirds is, 
 however, displaced through distances which 
 are different for every part of it, but which 
 may be represented by the distance between 
 the middle point of the lower half of the 
 two-thirds and the hole. So that the average 
 distance of displacement is a half of the 
 whole length of the worm-casting, Now the
 
 270 DENUDATION OF THE LAND CHAP. VI. 
 
 average length of ten out of the ahove eleven 
 castings was 2*03 inches, and half of this we 
 may take as heing 1 inch. It may therefore 
 be concluded that one-third of the whole 
 earth brought to the surface was in these 
 cases carried down the slope through 1 inch.* 
 It was shown in the third chapter that on 
 Leith Hill Common, dry earth weighing at 
 least 7'453 Ibs. was brought up by worms to 
 the surface on a square yard in the course of 
 a year. If a square yard be drawn on a 
 hill-side with two of its sides horizontal, then 
 it is clear that only -^g- part of the earth 
 brought up on that square yard would be 
 near enough to its lower side to cross it, 
 supposing the displacement of the earth to 
 be through one inch. But it appears that 
 only ^ of the earth brought up can be con- 
 sidered to flow downwards ; hence -g- of -^ or 
 y^-g- of V'453 Ibs. will cross the lower side of 
 our square yard in a year. Now -j-J^ of 
 7'453 Ibs. is I'l oz. Therefore I'l oz. of dry 
 earth will annually cross each linear yard run- 
 
 * Mr James Wallace Has pointed out that it is necessary to 
 take into consideration the possibility of burrows being made at 
 right angles to the surface instead of vertically down, in which 
 case the lateral displacement of the soil would be increased.
 
 CHAP. VI. AIDED BY WORMS. 271 
 
 ning horizontally along a slope having the 
 above inclination ; or very nearly 7 Ibs. will 
 annually cross a horizontal line, 100 yards in 
 length, on a hill-side having this inclination. 
 
 A more accurate, though still very rough, 
 calculation can be made of the bulk of earth, 
 which in its natural damp state annually 
 flows down the same slope over a yard-line 
 drawn horizontally across it. From the 
 several cases given in the third chapter, it 
 is known that the castings annually brought 
 to the surface on a square yard, if uniformly 
 spread out would form a layer *2 of an incli 
 in thickness : it therefore follows by a 
 calculation similar to the one already given, 
 that -J- of "2 x 36, or 2'4 cubic inches of damp 
 earth will annually cross a horizontal line one 
 yard in length on a hill-side with the above 
 inclination. This bulk of damp castings 
 was found to weigh 1*85 oz. Therefore 
 11*56 Ibs. of damp earth, instead of 7" Ibs. of 
 dry earth as by the former calculation, would 
 annually cross a line 100 yards in length on 
 our inclined surface. 
 
 In these calculations it has been assumed 
 that the castings flow a short distance down-
 
 272 DENUDATION OF THE LAND CHAP. VI. 
 
 wards during the whole year, but this occurs 
 only with those ejected during or shortly 
 before rain ; so that the above results are 
 thus far exaggerated. On the other hand, 
 during rain much of the finest earth is 
 washed to a considerable distance from the 
 castings, even where the slope is an ex- 
 tremely gentle one, and is thus wholly lost 
 as far as the above calculations are concerned. 
 Castings ejected during dry weather and 
 which have set hard, lose in the same 
 manner a considerable quantity of fine earth. 
 Dried castings, moreover, are apt to disinte- 
 grate into little pellets, which often roll or 
 are blown down any inclined surface. There- 
 fore the above result, namely, that 2'4 cubic 
 inches of earth (weighing T85 oz. whilst 
 damp) annually crosses a yard-line of the 
 specified kind, is probably not much if at all 
 exaggerated. 
 
 This amount is small ; but we should bear 
 in mind how many branching valleys inter- 
 sect most countries, the whole length of 
 which must be very great ; and that earth is 
 steadily travelling down both turf-covered 
 sides of each valley. For every 100 yards in
 
 CHAP. VI. AIDED BY WORMS. 273 
 
 length in a valley with sides sloping as in the 
 foregoing cases, 480 cubic inches of damp 
 earth, weighing above 23 pounds, will annu- 
 ally reach the bottom. Here a thick bed of 
 alluvium will accumulate, ready to be washed 
 away in the course of centuries, as the stream 
 in the middle meanders from side to side. 
 
 If it could be shown that worms generally 
 excavate their burrows at right angles to 
 an inclined surface, and this would be 
 their shortest course for bringing up earth 
 from beneath, then as the old burrows col- 
 lapsed from the weight of the superincum- 
 bent soil, the collapsing would inevitably 
 cause the whole bed of vegetable mould to 
 sink or slide slowly down the inclined sur- 
 face. But to ascertain the direction of many 
 burrows was found too difficult and trouble- 
 some. A straight piece of wire was, however, 
 pushed into twenty-five burrows on several 
 sloping fields, and in eight cases the burrows 
 were nearly at right angles to the slope ; whilst 
 in the remaining cases they were indifferently 
 directed at various angles, either upwards or 
 downwards with respect to the slope. 
 
 In countries where the rain is very heavy,
 
 274 DENUDATION OF THE LAND CHAP. VI, 
 
 as in the tropics, the castings appear, as 
 might have been expected, to be washed 
 down in a greater degree than in England. 
 Mr. Scott informs me that near Calcutta the 
 tall columnar castings (previously described), 
 the diameter of which is usually between 1 
 and 1^ inch, subside on a level surface, 
 after heavy rain, into almost circular, thin, 
 flat discs, between 3 and 4 and sometimes 5 
 inches in diameter. Three fresh castings, 
 which had been ejected in the Botanic 
 Gardens "on a slightly inclined, grass- 
 " covered, artificial bank of loamy clay," were 
 carefully measured, and had a mean height 
 of 2*17, and a mean diameter of T43 inches ; 
 these after heavy rain, formed elongated 
 patches of earth, with a mean length in the 
 direction of the slope of 5*83 inches. As the 
 earth had spread very little up the slope, a 
 large part, judging from the original diameter 
 of these castings, must hava flowed bodily 
 downwards about 4 inches. Moreover some 
 of the finest earth of which they were com- 
 posed must have been washed completely 
 away to a still greater distance. In drier 
 sites near Calcutta, a species of worm ejects
 
 CHAP. VI. AIDED BY WORMS. 275 
 
 its castings, not in vermiform masses, but in 
 little pellets of varying sizes : these are very 
 numerous in some places, and Mr. Scott says 
 that they " are washed away by every 
 " shower." 
 
 I was led to believe that a considerable 
 quantity of fine earth is washed quite away 
 from castings during rain, from the surfaces 
 of old ones being often studded with coarse 
 particles. Accordingly a little fine precipi- 
 tated chalk, moistened with saliva or gum- 
 water, so as to be slightly viscid and of the 
 same consistence as a fresh casting, was 
 placed on the summits of several castings and 
 gently mixed with them. These castings 
 were then watered through a very fine rose, 
 the drops from which were closer together 
 than those of rain, but not nearly so large as 
 those in a thunder-storm ; nor did they strike 
 the ground with nearly so much force as 
 drops during heavy rain. A casting thus 
 treated subsided with surprising slowness, 
 owing as I suppose to its viscidity. It did 
 not flow bodily down the grass-covered sur- 
 face of the lawn, which was here inclined at 
 an angle of 16 20'; nevertheless many pax 1 
 
 u
 
 276 DENUDATION OF THE LAND CHAP. VI. 
 
 tides of the chalk were found three inches 
 below the casting. The experiment was re- 
 peated on three other castings on different 
 parts of the lawn, which sloped at 2 30', 
 3 and 6; and particles of chalk could be 
 seen between 4 and 5 inches below the cast- 
 ing ; and after the surface had become dry, 
 particles were found in two cases at a distance 
 of 5 and 6 inches. Several other castings 
 with precipitated chalk placed on their 
 summits were left to the natural action of 
 the rain. In one case, after rain which was 
 not heavy, the casting was longitudinally 
 streaked with white. In two other cases the 
 surface of the ground was rendered some- 
 what white for a distance of one inch from 
 the casting ; and some soil collected at a dis- 
 tance of 2J- inches, where the slope was 7, 
 effervesced slightly when placed in acid. 
 After one or two weeks, the chalk was wholly 
 or almost wholly washed away from all the 
 castings on which it had been placed, and 
 these had recovered their natural colour. 
 
 It may be here remarked that after very 
 heavy rain shallow pools may be seen on level 
 or nearly level fields, where the soil is not
 
 CHAP. VI. AIDED BY WORMS 277 
 
 very porous, and the water in them is often 
 slightly muddy ; when such little pools have 
 dried, the leaves and blades of grass at their 
 bottoms are generally coated with a thin layer 
 of mud. This mud I believe is derived in 
 large part from recently ejected castings. 
 
 Dr. King informs me that the majority of 
 the before described gigantic castings, which 
 he found on a fully exposed, bare, gravelly 
 knoll on the Nilgiri Mountains in India, had 
 been more or less weathered by the previous 
 north-east monsoon ; and most of them pre- 
 sented a subsided appearance. The worms 
 here eject their castings only during the rainy 
 season ; and at the time of Dr. King's visit no 
 rain had fallen for 110 days. He carefully 
 examined the ground between the place 
 where these huge castings lay, and a little 
 water-course at the base of the knoll, and 
 nowhere was there any accumulation of fine 
 earth, such as would necessarily have been 
 left by the disintegration of the castings if 
 they had not been wholly removed. He 
 therefore has no hesitation in asserting that 
 the whole of these huge castings are annually 
 washed during the two monsoons (when 
 
 u 2
 
 278 DENUDATION OF THE LAND CHAP. VI. 
 
 about 100 inches of rain fall) into the little 
 water-course, and thence into the plains 
 lying below at a depth of 3000 or 4000 feet. 
 
 Castings ejected before or during dry 
 weather become hard, sometimes surprisingly 
 hard, from the particles of earth having been 
 cemented together by the intestinal secre- 
 tions. Frost seems to be less effective in 
 their disintegration than might have been 
 expected. Nevertheless they readily disin- 
 tegrate into small pellets, after being alter- 
 nately moistened with rain and again dried. 
 Those which have flowed during rain down a 
 slope, disintegrate in the same manner. Such 
 pellets often roll a little down any sloping 
 surface ; their descent being sometimes much 
 aided by the wind. The whole bottom of a 
 broad dry ditch in my grounds, where there 
 were very few fresh castings, was completely 
 covered with these pellets or disintegrated 
 castings, which had rolled down the steep 
 sides, inclined at an angle of 27. 
 
 Near Nice, in places where the great cylin- 
 drical castings, previously described, abound, 
 the soil consists of very fine arenaceo-cal- 
 careous loam ; and Dr. King informs me that
 
 CHAP. VI. AIDED BY WORMS. 279 
 
 these castings are extremely liable to crumble 
 during dry weather into small fragments, 
 which are soon acted on by rain, and then 
 sink down so as to be no longer distinguish- 
 able from the surrounding soil. He sent me 
 a mass of such disintegrated castings, collected 
 on the top of a bank, where none could have 
 rolled down from above. They must have 
 been ejected within the previous five or six 
 months, but they now consisted of more or less 
 rounded fragments of all sizes, from f of an 
 inch in diameter to minute grains and mere 
 dust. Dr. King witnessed the crumbling 
 process whilst drying some perfect castings, 
 which he afterwards sent me. Mr. Scott also 
 remarks on the crumbling of the castings 
 near Calcutta and on the mountains of 
 Sikkim during the hot and dry season. 
 
 When the castings near Nice had been 
 ejected on an inclined surface, the disinte- 
 grated fragments rolled downwards, without 
 losing their distinctive shape ; and in some 
 places could " be collected in basketfuls." Dr. 
 King observed a striking instance of this fact 
 on the Corniche road, where a drain, about 
 2^ feet wide and 9 inches deep, had been made
 
 280 DENUDATION TO LAND CHAP. VI. 
 
 to Catch the surface drainage from the adjoin- 
 ing hill-side. The bottom, of this drain was 
 covered for a distance of several hundred 
 yards, to a depth of from 1 J to 3 inches, by a 
 layer of broken castings, still retaining their 
 characteristic shape. Nearly all these in- 
 numerable fragments had rolled down from 
 above, for extremely few castings had been 
 ejected in the drain itself. The hill-side was 
 steep, but varied much in inclination, which 
 Dr. King estimated at from 30 to 60 with 
 the horizon. He climbed up the slope, and 
 " found every here and there little embank- 
 " ments, formed by fragments of the castings 
 " that had been arrested in their downward 
 " progress by irregularities of the surface, 
 " by stones, twigs, &c. One little group of 
 " plants of Anemone hortensis had acted in this 
 " manner, and quite a small bank of soil had 
 "collected round it. Much of this soil had 
 " crumbled down, but a great deal of it still 
 " retained the form of castings." Dr. King 
 dug up this plant, and was struck with 
 the thickness of the soil which must have 
 recently accumulated over the crown of the 
 rhizoma, as shown by the length of the
 
 CHAP. VI. LEDGES ON HILL-SIDES. 281 
 
 bleached petioles, in comparison with those 
 of other plants of the same kind, where 
 there had been no such accumulation. The 
 earth thus accumulated had no doubt been 
 secured (as I have everywhere seen) by the 
 smaller roots of the plants. After describing 
 this and other analogous cases, Dr. King con- 
 cludes : " I can have no doubt that worms 
 " help greatly in the process of denudation." 
 
 Ledges of earth on steep hill-sides. Little 
 horizontal ledges, one above another, have been 
 observed on steep grassy slopes in many parts 
 of the world. Their formation has been 
 attributed to animals travelling repeatedly 
 along the slope in the same horizontal lines 
 while grazing, and that they do thus move and 
 use the ledges is certain ; but Professor Hens- 
 low (a most careful observer) told Sir J. Hooker 
 that he was convinced that this was not the 
 sole cause of their formation. Sir J. Hooker 
 saw such ledges on the Himalayan and Atlas 
 ranges, where there were no domesticated 
 animals and not many wild ones ; but these 
 latter would, it is probable, use the ledges at 
 night while grazing like our domesticated 
 animals. A friend observed for me the ledges
 
 282 DENUDATION TO LAND CHAP. VI 
 
 on the Alps of Switzerland, and states that 
 they ran at 3 or 4 ft. one above the other, 
 and were about a foot in breadth. They had 
 been deeply pitted by the feet of grazing cows. 
 Similar ledges were observed by the same 
 friend on our Chalk downs, and on an old 
 talus of chalk-fragments (thrown out of a 
 quarry) which had become clothed with turf. 
 My son Francis examined a Chalk escarp- 
 ment near Lewes ; and here on a part which 
 was very steep, sloping at 40 with the 
 horizon, about 30 flat ledges extended hori- 
 zontally for more than 100 yards, at an average 
 distance of about 20 inches, one beneath the 
 other. They were from 9 to 10 inches in 
 breadth. When viewed from a distance they 
 presented a striking appearance, owing to their 
 parallelism ; but when examined closely, they 
 were seen to be somewhat sinuous, and one 
 often ran into another, giving the appearance 
 of the lodge having forked into two. They 
 are formed of light-coloured earth, which on 
 the outside, where thickest, was in one case 
 9 inches, and in another case between 6 and 
 7 inches in thickness. Above the ledges, the 
 thickness of the earth over the chalk was in
 
 HAP. VI. LEDGES ON HILL-SIDES. 283 
 
 the former case 4 and in the latter only 3 
 inches. The grass grew more vigorously on 
 the outer edges of the ledges than on any 
 other part of the slope, and here formed a 
 tufted fringe. Their middle part was bare, but 
 whether this had been caused by the trampling 
 of sheep, which sometimes frequent the ledges, 
 my son could not ascertain. Nor could he 
 feel sure how much of the earth on the middle 
 and bare parts, consisted of disintegrated 
 worm-castings which had rolled down from 
 above ; but he felt convinced that some had 
 thus originated ; and it was manifest that the 
 ledges with their grass-fringed edges would 
 arrest any small object rolling down from 
 above. 
 
 At one end or side of the bank bearing 
 these ledges, the surface consisted in parts of 
 bare chalk, and here the ledges were very 
 irregular. At the other end of the bank, the 
 slope suddenly became less steep, and here the 
 ledges ceased rather abruptly ; but little em- 
 bankments only a foot or two in length were 
 still present. The slope became steeper lower 
 down the hill, and the regular ledges then re- 
 appeared. Another of my sons observed, on
 
 284 DENUDATION TO LAND CHAP. VL 
 
 the inland side of Beacliy Head, where the 
 surface sloped at about 25, many short little 
 embankments like those just mentioned. 
 They extended horizontally and were from a 
 few inches to two or three feet in length. 
 They supported tufts of grass growing 
 vigorously. The average thickness of the 
 mould of which they were formed, taken 
 from nine measurements, was 4*5 inches; 
 while that of the mould above and beneath 
 them was on an average only 3*2 inches, and 
 on each side, on the same level, 3*1 inches. 
 On the upper parts of the slope, these em- 
 bankments showed no signs of having been 
 trampled on by sheep, but in the lower parts 
 such signs were fairly plain. No long con- 
 tinuous ledges had here been formed. 
 
 If the little embankments above the Cor- 
 niche road, which Dr. King saw in the act 
 of formation by the accumulation of dis- 
 integrated and rolled worm-castings, were to 
 become confluent along horizontal lines, ledges 
 would be formed. Each embankment would 
 tend to extend laterally by the lateral extension 
 of the arrested castings; and animals grazing on 
 a steep slope would almost certainly make use
 
 CHAP. VI. LEDGES ON HILL-SIDES. 285 
 
 of every prominence at nearly the same level, 
 and would indent the turf between them ; and 
 such intermediate indentations would again 
 arrest the castings. An irregular ledge when 
 once formed would also tend to become more 
 regular and horizontal by some of the castings 
 rolling laterally from the higher to the lower 
 parts, which would thus be raised. Any pro- 
 jection beneath a ledge would not afterwards 
 receive disintegrated matter from above, 
 and would tend to be obliterated by rain and 
 other atmospheric agencies. There is some 
 analogy between the formation, as here sup- 
 posed, of these ledges, and that of the ripples 
 of wind-drifted sand as described by Lyell.* 
 
 The steep, grass-covered sides of a 
 mountainous valley in Westmoreland, called 
 Grisedale, was marked in many places with 
 innumerable lines of miniature cliffs, with 
 almost horizontal, little ledges at their bases. 
 Their formation was in no way connected with 
 the action of worms, for castings could not 
 anywhere be seen (and their absence is an 
 inexplicable fact), although the turf lay in 
 many places over a considerable thickness of 
 
 * 'Elements of Geology,' 1865, p. 20.
 
 286 DENUDATION OF THE LAND. CHAP. VI. 
 
 boulder-clay and moraine rubbish. Nor, as 
 far as I could judge, was the formation of 
 these little cliffs at all closely connected with 
 the trampling of cows or sheep. It appeared 
 as if the whole superficial, somewhat argil- 
 laceous earth, while partially held together 
 by the roots of the grasses, had slided a little 
 way down the mountain sides; and in thus 
 sliding, had yielded and cracked in horizontal 
 lines, transversely to the slope. 
 
 Castings blown to leeward by the wind. We 
 have seen that moist castings flow, and that 
 disintegrated castings roll down any inclined 
 surface ; and we shall now see that castings, 
 recently ejected on level grass-covered 
 surfaces, are blown during gales of wind ac- 
 companied by rain to leeward. This has been 
 observed by me many times on many fields 
 during several successive years. After such 
 gales, the castings present a gently inclined 
 and smooth, or sometimes furrowed, surface 
 to windward, while they are steeply inclined 
 or precipitous to leeward, so that they resem- 
 ble on a miniature scale glacier-ground hillocks 
 of rock. They are often cavernous on the
 
 CHAP. VI. CASTINGS BLOWN TO LEEWAKD. 287 
 
 leeward side, from the upper part having 
 curled over the lower part During one un- 
 usually heavy south-west gale with torrents 
 of rain, many castings were wholly blown to 
 leeward, so that the mouths of the burrows 
 were left naked and exposed on the windward 
 side. Eecent castings naturally flow down 
 an inclined surface, but on a grassy field, 
 which sloped between 10 and 15, several 
 were found after a heavy gale blown up the 
 slope. This likewise occurred on another 
 occasion on a part of my lawn where the 
 slope was somewhat less. On a third occasion, 
 the castings on the steep, grass-covered sides 
 of a valley, down which a gale had blown, 
 were directed obliquely instead of straight 
 down the slope ; and this was obviously due 
 to the combined action of the wind and 
 gravity. Four castings on my lawn, where 
 the downward inclination was 45', 1, 3 and 
 3 30' (mean 2 45') towards the north-east, 
 after a heavy south-west gale with rain, were 
 divided across the mouths of the burrows and 
 weighed in the manner formerly described. 
 The mean weight* of the earth below the 
 mouths of burrows and to leeward, was to that
 
 288 DENUDATION OF THE LAND. CHAP. VI. 
 
 above the mouths and on the windward side 
 as 2 1 to 1 ; whereas we have seen that with 
 several castings which had flowed down slopes 
 having a mean inclination of 9 26', and with 
 three castings where the inclination was 
 above 12, the proportional weight of the 
 earth below to that above the burrows was 
 as only 2 to 1. These several cases show how 
 efficiently gales of wind accompanied by rain 
 act in displacing recently-ejected castings. 
 "We may therefore conclude that even a 
 moderately strong wind will produce some 
 slight effect on them 
 
 Dry and indurated castings, after their dis- 
 integration into small fragments or pellets, are 
 sometimes, probably often, blown by a strong 
 wind to leeward. This was observed on four 
 occasions, but I did not sufficiently attend to 
 this point. One old casting on a gently slop- 
 ing bank was blown quite away by a strong 
 south-west wind. Dr. King believes that 
 the wind removes the greater part of the 
 old crumbling castings near Nice. Several 
 old castings on my lawn were marked with 
 pins and protected from any disturbance. 
 They were examined after an interval of 10
 
 CHAP. VI. CASTINGS BLOWN TO LEEWAED. 289 
 
 weeks, during which time the weather had 
 been alternately dry and rainy. Some, which 
 were of a yellowish colour had been washed 
 almost completely away, as could be seen 
 by the colour of the surrounding ground. 
 Others had completely disappeared, and these 
 no doubt had been blown away. Lastly, 
 others still remained and would long remain, 
 as blades of grass had grown through them. 
 On poor pasture land, which has never been 
 rolled and has not been much trampled on 
 by animals, the whole surface is sometimes 
 dotted with little pimples, through and on 
 which grass grows; and these pimples con- 
 sist of old worm-castings. 
 
 In all the many observed cases of soft cast 
 ings blown to leeward, this had been effected 
 by strong winds accompanied by rain. As 
 such winds in England generally blow from 
 the south and south-west, earth must on the 
 whole tend to travel over our fields in a 
 north and north-east direction. This fact is 
 interesting, because it might be thought that 
 none could be removed from a level, grass- 
 covered surface by any means. In thick and 
 level woods, protected from the wind, castings
 
 290 DENUDATION OF THE LAND. CHAP. VI 
 
 will never be removed as long as the wood 
 lasts ; and mould will here tend to accumulate 
 to the depth at which worms can work. I 
 tried to procure evidence as to how much 
 mould is blown, whilst in the state of cast- 
 ings, by our wet southern gales to the north- 
 east, over open and flat land, by looking to 
 the level of the surface on opposite sides of 
 old trees and hedge-rows ; but I failed owing 
 to the unequal growth of the roots of trees 
 and to most pasture-land having been formerly 
 ploughed. 
 
 On an open plain near Stonehenge, there 
 exist shallow circular trenches, with a low 
 embankment outside, surrounding level spaces 
 50 yards in diameter. These rings appear 
 very ancient, and are believed to be contem- 
 poraneous with the Druidical stones. Castings 
 ejected within these circular spaces, if blown 
 to the north-east by south-west winds would 
 form a layer of mould within the trench, 
 thicker on the north-eastern than on any other 
 side. But the site was not favourable for the 
 action of worms, for the mould over the 
 surrounding Chalk formation with flints, was 
 only 3-37 inches in thickness, from a mean of
 
 CHAP. VI. CASTINGS BLOWN TO LEEWARD. 291 
 
 six observations made at a distance of 10 yards 
 outside the embankment. The thickness of 
 the mould within two of the circular trenches 
 was measured every 5 yards all round, on the 
 inner sides near the bottom. My son Horace- 
 protracted these measurements on paper ; and 
 though the curved line representing the thick- 
 ness of the mould was extremely irregular, yet 
 in both diagrams it could be seen to be thicker 
 on the north-eastern side than elsewhere. 
 When a mean of all the measurements in both- 
 the trenches was laid down and the line- 
 smoothed, it was obvious that the mould was 
 thickest in the quarter of the circle between- 
 north-west and north-east; and thinnest in> 
 the quarter between south-east and south- 
 west, especially at this latter point. Besides 
 the foregoing measurements, six others were- 
 taken near together in one of the circular 
 trenches, on the north-east side; and the- 
 mould here had a mean thickness of 2*29' 
 inches ; while the mean of six other measure- 
 ments on the south-west side was only 1'46- 
 inches. These observations indicate that the 
 castings had been blown by the south-west 
 winds from the circular enclosed space into 
 
 x
 
 292 DENUDATION OF THE LAND. CHAP. VI. 
 
 the trench on the north-east side ; but many 
 more measurements in other analogous cases 
 would be requisite for a trustworthy result. 
 
 The amount of fine earth brought to the 
 surface under the form of castings, and after- 
 wards transported by the winds accompanied 
 by rain, or that which flows and rolls down 
 an inclined surface, no doubt is small in the 
 course of a few scores of years ; for otherwise 
 all the inequalities in our pasture fields would 
 be smoothed within a much shorter period 
 than appears to be the case. But the amount 
 which is thus transported in the course of 
 thousands of years cannot fail to be consider- 
 able and deserves attention. E. de Beaumont 
 looks at the vegetable mould which every- 
 where covers the land as a fixed line, 
 from which the amount of denudation may 
 be measured.* He ignores the continued 
 formation of fresh mould by the disintegra- 
 tion of the underlying rocks and fragments of 
 rock ; and it is curious to find how much 
 more philosophical were the views, main- 
 
 * 'Le9ons de Geologic pratique, 1845; cinquieme Lecon.' 
 All Elie de Beaumont's arguments are admirably controverted 
 by Prof. A. Geikie in his essay in Transact. Geolog. Soc. of 
 Glasgow, vol. iii. p. 153, 1868.
 
 'CHAP. VI. ANCIENT MOUNDS. 293 
 
 tained long ago, by Play fair, who, In 1802, 
 wrote, "In the permanence of a coat of 
 " vegetable mould on the surface of the earth, 
 " we have a demonstrative proof of the con- 
 "*' tinued destruction of the rocks."* 
 
 Ancient encampments and tumuli. E. de 
 Beaumont adduces the present state of many 
 ancient encampments and tumuli and of old 
 ploughed fields, as evidence that the surface 
 of the land undergoes hardly any degradation. 
 But it does not appear that he ever examined 
 ~fche thickness of the mould over different 
 parts of such old remains. He relies chiefly 
 on indirect, but apparently trustworthy, evi- 
 dence that the slopes of the old embankments 
 are the same as they originally were ; and it 
 is obvious that he could know nothing about 
 their original heights. In Knole Park a 
 mound had been thrown up behind the rifle- 
 targets, which appeared to have been formed 
 of earth originally supported by square blocks 
 of turf. The sides sloped, as nearly as I could 
 estimate them, at an angle of 45 or 50 with 
 the horizon, and they were covered, especially 
 on the northern side, with long coarse grass, 
 
 * * Illustrations of the Huttonian Theory of the Earth,' p. 107. 
 
 x 2
 
 294 DENUDATION OF THE LAND. CHAP. VL 
 
 beneath which many worm-castings were 
 found. These had flowed bodily downwards, 
 and others had rolled down as pellets. Hence 
 it is certain that as long as a mound of this 
 kind is tenanted by worms, its height will be 
 continually lowered. The fine earth which 
 flows or rolls down the sides of such a mound 
 accumulates at its base in the form of a talus. 
 A bed, even a very thin bed, of fine earth is 
 eminently favourable for worms ; so that a 
 greater number of castings would tend to be 
 ejected on a talus thus formed than elsewhere ; 
 and these would be partially washed away by 
 every heavy shower and be spread over the 
 adjoining level ground. The final result 
 would be the lowering of the whole mound,, 
 whilst the inclination of the sides would not 
 be greatly lessened. The same result would 
 assuredly follow with ancient embankments 
 and tumuli ; except where they had been 
 formed of gravel or of nearly pure sand, as such 
 matter is unfavourable for worms. Many old 
 fortifications and tumuli are believed to be at 
 least 2000 years old ; and we should bear in 
 mind that in many places about one inch of 
 mould is brought to the surface in 5 years or
 
 CHAP. VI. ANCIENTLY PLOUGHED FIELDS. 295 
 
 two inches in 10 years. Therefore in so long 
 a period as 2000 years, a large amount of 
 earth will have heen repeatedly brought to 
 the surface on most old embankments and 
 tumuli, especially on the talus round their 
 bases, and much of this earth will have been 
 washed completely away. We may therefore 
 conclude that all ancient mounds, when not 
 formed of materials unfavourable to worms, 
 will have been somewhat lowered in the 
 course of centuries, although their inclina- 
 tions may not have been greatly changed. 
 
 Fields formerly ploughed. From a very 
 remote period and in many countries, land 
 has been ploughed, so that convex beds, 
 called crowns or ridges, usually about 8 feet 
 across and separated by furrows, have been 
 thrown up. The furrows are directed so as 
 to carry off the surface water. In my 
 attempts to ascertain how long a time these 
 crowns and furrows last, when ploughed land 
 has been converted into pasture, obstacles of 
 many kinds were encountered. It is rarely 
 kuown when a field was last ploughed ; and 
 some fields which were thought to have been 
 in pasture from time immemorial were after-
 
 296* DENUDATION OF THE LAND. CHAP. VI.. 
 
 wards discovered to- have- been ploughed only 
 50 or 60 years before. During the early 
 part of the present century, when the price 
 of corn was very high, land of all kinds seems 
 to have been ploughed in Britain. There is, 
 however, no reason to doubt that in many 
 cases the old crowns and furrows have been 
 preserved from a very ancient period.* That 
 they should have been preserved for very 
 unequal lengths of time would naturally 
 follow from the crowns, when first thrown 
 up, having differed much in height in dif- 
 ferent districts, as is now the case with 
 recently ploughed land. 
 
 In old pasture fields, the mould, wherever 
 measurements were made, was found to be 
 from i to 2 inches thicker in the furrows than 
 
 * Mr. E. Tylor in his Presidential address ('Journal of the 
 Anthropological Institute,' May 1880, p. 451) remarks: "It 
 appears from several papers of the Berlin Society as to the 
 German 'high-fields' or 'heathen-fields' (Hochacker, and 
 Heidenacker) that they correspond much in their situation on hills 
 and wastes with the * elf-furrows ' of Scotland, which popular 
 mythology accounts for by the story of the fields having been 
 put under a Papal interdict, so that people took to cultivating 
 the hills.- There seems reason to suppose that, like the tilled 
 plots in the Swedish forests which tradition ascribes to the old 
 * hackers,' the German- heathen-fields represent tillage by an. 
 ancient and barbaric population."
 
 CHAP. VI. ANCIENTLY PLOUGHED FIELDS. 297 
 
 on the crowns ; but this would naturally 
 follow from the finer earth having been 
 washed from the crowns into the furrows 
 before the land was well clothed with turf; 
 and it is impossible to tell what part worms 
 may have played in the work. Nevertheless 
 from what we have seen, castings would 
 certainly tend to flow and to be washed during 
 heavy rain from the crowns into the furrows. 
 But as soon as a bed of fine earth had by any 
 means been accumulated in the furrows, it 
 would be more favourable for worms than the 
 other parts, and a greater number of castings 
 would be thrown up here than elsewhere ; and 
 as the furrows on sloping land are usually 
 directed so as to carry off the surface water, 
 some of the finest earth would be washed 
 from the castings which had been here ejected 
 and be carried completely away. The result 
 would be that the furrows would be filled 
 up very slowly, while the crowns would be 
 lowered perhaps still more slowly by the 
 flowing and rolling of the castings down 
 their gentle inclinations into the furrows. 
 
 Nevertheless it might be expected that old 
 furrows, especially those on a sloping surface,
 
 -298 DENUDATION OF THE LAND. CHAP. VI. 
 
 would in the course of time be filled up and 
 disappear. Some careful observers, however, 
 who examined fields for me in Gloucestershire 
 and Staffordshire, could not detect any dif- 
 ference in the state of the furrows in the 
 upper and lower parts of sloping fields, sup- 
 posed to have been long in pasture ; and they 
 came to the conclusion that the crowns and 
 furrows would last for an almost endless 
 number of centuries. On the other hand the 
 process of obliteration seems to have com- 
 menced in some places. Thus in a grass 
 field in North Wales, known to have been 
 ploughed about 65 years ago, which sloped at 
 an angle of 15 to the north-east, the depth 
 of the furrows (only 7 feet apart) was care- 
 fully measured, and was found to be about 
 4 J inches in the upper part of the slope, and 
 only 1 inch near the base, where they could 
 be traced with difficulty. On another field 
 sloping at about the same angle to the south- 
 west, the furrows were scarcely perceptible 
 in the lower part ; although these same 
 furrows when followed on to some adjoining 
 level ground were from 2^ to 3J inches in 
 depth. A third and closely similar case was
 
 OHAP. VI. ANCIENTLY PLOUGHED FIELDS. 299 
 
 observed. In a fourth case, the mould in a 
 furrow in the upper part of a sloping field 
 was 2J inches, and in the lower part 4^ 
 inches in thickness. 
 
 On the Chalk Downs at about a mile dis- 
 tance from Stonehenge, my son William ex- 
 amined a grass-covered, furrowed surface, 
 sloping at from 8 to 10, which an old shep- 
 herd said had not been ploughed within the 
 memory of man. The depth of one furrow 
 was measured at 16 points in a length of 68 
 paces, and was found to be deeper where the 
 slope was greatest and where less earth would 
 naturally tend to accumulate, and at the 
 base it almost disappeared. The thickness of 
 the mould in this furrow in the upper part 
 was 2t| inches, which increased to 5 inches a 
 little above the steepest part of the slope ; and 
 at the base, in the middle of the narrow 
 valley, at a point which the furrow if con- 
 iinued would have struck, it amounted to 7 
 inches. On the opposite side of the valley, 
 there were very faint, almost obliterated, 
 traces of furrows. Another analogous but 
 not so decided a case was observed at a few 
 miles' distance from Stonehenge. On the
 
 300 DENUDATION OF THE LAND. CHAP. VI. 
 
 whole it appears that the crowns and fur- 
 rows on land formerly ploughed, but now 
 covered with grass, tend slowly to disappear 
 when the surface is inclined ; and this is pro- 
 bably in large part due to the action of 
 worms ; but that the crowns and furrows last 
 for a very long time when the surface is 
 nearly level. 
 
 Formation and amount of mould over the 
 Chalk Formation. Worm-castings are often 
 ejected in extraordinary numbers on steep, 
 grass-covered slopes, where the Chalk comes 
 close to the surface, as my son William 
 observed near Winchester and elsewhere. If 
 such castings are largely washed away during 
 heavy rains, it is difficult to understand at 
 first how any mould can still remain on our 
 Downs, as there does not appear any evident 
 means for supplying the loss. There is, more- 
 over, another cause of loss, namely, in the per- 
 colation of the finer particles of earth into the 
 fissures in the chalk and into the chalk itself. 
 These considerations led me to doubt for a time 
 whether I had not exaggerated the amount 
 of fine earth which flows or rolls down grass- 
 covered slopes under the form of castings ; and
 
 CHAP. VI. MOULD OVER THE CHALK. SOX 
 
 I sought for additional information. In some 
 places, the castings on Chalk Downs consist 
 largely of calcareous matter, and here the 
 supply is of course unlimited. But in other- 
 places, for instance on a part of Teg Down 
 near Winchester, the castings were all black 
 and did not effervesce with acids. The mould 
 over the chalk was here only from 3 to 4 
 inches in thickness. So again on the plain 
 near Stonehenge, the mould, apparently free 
 from calcareous matter, averaged rather less 
 than 3J inches in thickness. Why worms 
 should penetrate and bring up chalk in some 
 places and not in others I do not know. 
 
 In many districts where the land is nearly 
 level, a bed several feet in thickness of red 
 clay full of unworn flints overlies the Upper 
 Chalk. This overlying matter, the surface 
 of which has been converted into mould, con- 
 sists of the undissolved residue from the chalk. 
 It may be well here to recall the case of the 
 fragments of chalk buried beneath worm- 
 castings on one of my fields, the angles of 
 which were so completely rounded in the 
 course of 29 years that the fragments now 
 resembled water-worn pebbles. This must
 
 302 DENUDATION OF THE LAND. CHAP. VL 
 
 have been effected by the carbonic acid in 
 the rain and in the ground, by the humus- 
 acids, and by the corroding power of living 
 roots. Why a thick mass of residue has not 
 been left on the Chalk, wherever the land is 
 nearly level, may perhaps be accounted for 
 by the percolation of the fine particles into 
 the fissures, which are often present in the 
 chalk and are either open or are filled up 
 with impure chalk, or into the solid chalk 
 itself. That such percolation occurs can 
 hardly be doubted. My son collected some 
 powdered and fragmentary chalk beneath the 
 turf near Winchester ; the former was found 
 by Colonel Parsons, R.E., to contain 10 per 
 cent., and the fragments 8 per cent, of earthy 
 matter. On the flanks of the escarpment near 
 Abinger in Surrey, some chalk close beneath 
 a layer of flints, 2 inches in thickness and 
 covered by 8 inches of mould, yielded a re- 
 sidue of 3'7 per cent, of earthy matter. On 
 the other hand the Upper Chalk properly 
 contains, as I was informed by the late David 
 Forbes who had made many analyses, only 
 from 1 to 2 per cent, of earthy matter ; and 
 two samples from pits near my house con-
 
 CHAP. VI. MOULD OVER THE CHALK. SOS 
 
 tained 1*3 and 0'6 per cent. I mention these 
 latter cases because, from the thickness of the 
 overlying bed of red clay with flints, I had 
 imagined that the underlying chalk might 
 here be less pure than elsewhere. The cause 
 of the residue accumulating more in some 
 places than in others, may be attributed to a 
 layer of argillaceous matter having been left 
 at an early period on the chalk, and this 
 would check the subsequent percolation of 
 earthy matter into it. 
 
 From the facts now given we may conclude 
 that castings ejected on our Chalk Downs suffer 
 some loss by the percolation of their finer 
 matter into the chalk. But such impure 
 superficial chalk, when dissolved, would leave 
 a larger supply of earthy matter to be 
 added to the mould than in the case of pure 
 chalk. Besides the loss caused by percola- 
 tion, some fine earth is certainly washed 
 down the sloping grass-covered surfaces of 
 our Downs. The washing-down process, how- 
 ever, will be checked in the course of time ; 
 for although I do not know how thin a layer 
 of mould suffices to support worms, yet a limit 
 must at last be reached ; and then their cast-
 
 304 DENUDATION OF THE LAND. CHAP. VI. 
 
 ings would cease to be ejected or would 
 become scanty. 
 
 The following cases show that a consider- 
 able quantity of fine earth is washed down. 
 The thickness of the mould was measured at 
 points 12 yards apart across a small valley 
 in the Chalk near Winchester. The sides 
 sloped gently at first ; then became inclined 
 at about 20 ; then more gently to near the 
 bottom, which transversely was almost level 
 and about 50 yards across. In the bottom, 
 the mean thickness of the mould from five 
 measurements was 8'3 inches; whilst on the 
 sides of the valley, where the inclination 
 varied between 14 and 20, its mean thick- 
 ness was rather less than 3*5 inches. As the 
 turf-covered bottom of the valley sloped at an 
 angle of only between 2 and 3, it is probable 
 that most of the 8'3-inch layer of mould had 
 been was'hed down from the flanks of the 
 valley, and not from the upper part. But as 
 a shepherd said that he had seen water flow- 
 ing in this valley after the sudden thawing of 
 snow, it is possible that some earth may have 
 been brought down from the upper part ; or, 
 on the other hand, that some may have been
 
 CHAP. VI. MOULD OVER THE CHALK. 305 
 
 carried further down the valley. Closely 
 similar results, with respect to the thickness of 
 the mould, were obtained in a neighbouring 
 valley. 
 
 St. Catherine's Hill, near Winchester, is 
 327 feet in height, and consists of a steep 
 cone of chalk about 1 of a mile in diameter. 
 The upper part was converted by the Romans, 
 or, as some think, by the ancient Britons, into 
 an encampment, by the excavation of a deep 
 and broad ditch all round it. Most of the 
 chalk removed during the work was thrown 
 upwards, by which a projecting bank was 
 formed ; and this effectually prevents worm- 
 castings (which are numerous in parts), stones, 
 and other objects from being washed or rolled 
 into the ditch. The mould on the upper and 
 fortified part of the hill was found to be in 
 most places only from 2J to 3^ inches in 
 thickness ; whereas it had accumulated at the 
 foot of the embankment above the ditch to a 
 thickness in most places of from 8 to 9J 
 inches. On the embankment itself the mould 
 was only 1 to 1J inch in thickness; and 
 within the ditch at the bottom it varied from 
 2% to 3J, but was in one spot 6 inches in
 
 306 DENUDATION OP THE LAND. CHAP. VL 
 
 thickness. On the north-west side of the 
 hill, either no embankment had ever heen 
 thrown up above the ditch, or it had subse- 
 quently been removed ; so that here there 
 was nothing to prevent worm-castings, earth 
 and stones being washed into the ditch, at the 
 bottom of which the mould formed a layer 
 from 11 to 22 inches in thickness. It should 
 however be stated that here and on other 
 parts of the slope, the bed of mould often con- 
 tained fragments of chalk and flint which 
 had obviously rolled down at different times 
 from above. The interstices in the under- 
 lying fragmentary chalk were also filled up 
 with mould. 
 
 My son examined the surface of this hill to 
 its base in a south-west direction. Beneath 
 the great ditch, where the slope was about 
 24, the mould was very thin, namely, from 
 l to 2 inches ; whilst near the base, where 
 the slope was only 3 to 4, it increased to 
 between 8 and 9 inches in thickness. We 
 may therefore conclude that on this artificially 
 modified hill, as well as in the natural valleys 
 of the neighbouring Chalk Downs, some fine 
 earth, probably derived in large part from
 
 CHAP. VI. MOULD OVER THE CHALK. 307 
 
 worm-castings, is washed down, and accumu- 
 lates in the lower parts, notwithstanding the 
 percolation of an unknown quantity into the 
 underlying chalk ; a supply of fresh earthy 
 matter being afforded by the dissolution of 
 the chalk through atmospheric and other 
 agencies.
 
 30& CONCLUSION. CHAP. VIL 
 
 CHAPTER VII. 
 
 CONCLUSION. 
 
 Summary of the part which worms have played in the history 
 of the world Their aid in the disintegration of rocks In the 
 denudation of the land In the preservation of ancient remains- 
 In the preparation of the soil for the growth of plants 
 Mental powers of worms Conclusion. 
 
 WORMS have played a more important part 
 in the history of the world than most persons 
 would at first suppose. In almost all humid 
 countries they are extraordinarily numerous, 
 and for their size possess great muscular 
 power. In many parts of England a weight 
 of more than ten tons (10,516 kilogrammes) 
 of dry earth annually passes through their 
 bodies and is brought to the surface on each 
 acre of land ; so that the whole superficial 
 bed of vegetable mould passes through their 
 bodies in the course of every few years 
 From the collapsing of the old burrows the 
 mould is in constant though slow movement,
 
 CHAP. VII. CONCLUSION. 309 
 
 and the particles composing it are thus 
 rubbed together. By these means fresh sur- 
 faces are continually exposed to the action of 
 the carbonic acid in the soil, and of the 
 humus-acids which appear to be still more 
 efficient in the decomposition of rocks. The 
 generation of the humus-acids is probably 
 hastened during the digestion of the many 
 half-decayed leaves which worms consume. 
 Thus the particles of earth, forming the 
 superficial mould, are subjected to conditions 
 eminently favourable for their decomposition 
 and disintegration. Moreover, the particles 
 of the softer rocks suffer some amount of 
 mechanical trituration in the muscular giz- 
 zards of worms, in which smail stones serve 
 as mill-stones. 
 
 The finely levigated castings, when brought 
 to the surface in a moist condition, flow during 
 rainy weather down any moderate slope ; and 
 the smaller particles are washed far down 
 even a gently inclined surface. Castings 
 when dry often crumble into small pellets 
 and these are apt to roll down any sloping 
 surface. Where the land is quite level and 
 is covered with herbage, and where the 
 
 T 2
 
 CONCLUSION. CHAP. VIL 
 
 climate is humid so that much dust cannot be 
 blown away, it appears at first sight im- 
 possible that there should be any appreciable 
 amount of sub-aerial denudation ; but worm- 
 'Castings are blown, especially whilst moist 
 and viscid, in one uniform direction by the 
 prevalent winds which are accompanied by 
 rain. By these several means the superficial 
 mould is prevented from accumulating to a 
 great thickness ; and a thick bed of mould 
 checks in many ways the disintegration of 
 ,the underlying rocks and fragments of rock. 
 
 The removal of worm-castings by the above 
 i means leads to results which are far from 
 insignificant. It has been shown that a 
 layer of earth, *2 of an inch in thickness, is in 
 many places annually brought to the surface ; 
 .and if a small part of this amount flows, or 
 rolls, or is washed, even for a short distance, 
 down every inclined surface, or is repeatedly 
 blown in one direction, a great effect will 
 Jbe produced in the course of ages. It was 
 found by measurements and calculations that 
 on a surface with a mean inclination of 
 9 26', 2'4 cubic inches of earth which had 
 been ejected by worms crossed, in the course
 
 CHAP. VII. CONCLUSION. 31$ 
 
 of a year, a horizontal line one yard in length; 
 so that 240 cubic inches would cross a line 
 100 yards in length. This latter amount in a 
 damp state would weigh 114 pounds. Thus- 
 a considerable weight of earth is continually 
 moving down each side of every valley, and 
 will in time reach its bed. Finally this earth 
 will be transported by the streams flowing in 
 the valleys into the ocean, the great receptacle- 
 for all matter denuded from the land. It is- 
 known from the amount of sediment annually 
 delivered into the sea by the Mississippi, that 
 its enormous drainage-area must on an aver- 
 age be lowered "00263 of an inch each year - 
 and this would suffice in four and half million 
 years to lower the whole drainage-area to the 
 level of the sea-shore. So that, if a small- 
 fraction of the layer of fine earth, -2 of an 
 inch in thickness, which is annually brought 
 to the surface by worms, is carried away, a 
 great result cannot fail to be produced within 
 a period which no geologist considers ex- 
 tremely long. 
 
 Archaeologists ought to be grateful to 
 worms, as they protect and preserve for ai>
 
 812 CONCLUSION. CHAP. VII. 
 
 indefinitely long period every object, not 
 liable to decay, which is dropped on the 
 surface of the land, by burying it beneath 
 their castings. Thus, also, many elegant and 
 curious tesselated pavements and other ancient 
 remains have been preserved ; though no 
 doubt the worms have in these cases been 
 largely aided by earth washed and blown 
 from the adjoining land, especially when cul- 
 tivated. The old tesselated pavements have, 
 however, often suffered by having subsided 
 unequally from being unequally undermined 
 by the worms. Even old massive walls may 
 be undermined and subside ; and no building 
 is in this respect safe, unless the foundations 
 lie 6 or 7 feet beneath the surface, at a depth 
 at which worms cannot work. It is probable 
 that many monoliths and some old walls have 
 fallen down from having been undermined 
 by worms. 
 
 Worms prepare the ground* in an excel- 
 lent manner for the growth of fibrous-rooted 
 plants and for seedlings of all kinds. They 
 
 * White of Selborne has some good remarks on the service 
 performed by worms in loosening, &c., the soiL Edit, by 
 L. Jenyns, 1843, p. 281.
 
 CHAP. VII. CONCLUSION. 313 
 
 periodically expose the mould to the air, and 
 sift it so that no stones larger than the par- 
 ticles which they can swallow are left in it 
 They mingle the whole intimately together, 
 like a gardener who prepares fine soil for his 
 choicest plants. In this state it is well fitted 
 to retain moisture and to absorb all soluble 
 substances, as well as for the process of nitri- 
 fication. The bones of dead animals, the 
 liarder parts of insects, the shells of land- 
 molluscs, leaves, twigs, &c., are before long 
 all buried beneath the accumulated castings of 
 worms, and are thus brought in a more or 
 less decayed state within reach of the roots 
 of plants. Worms likewise drag an infinite 
 number of dead leaves and other parts of 
 plants into their burrows, partly for the sake 
 of plugging them up and partly as food. 
 
 The leaves which are dragged into the bur- 
 TOWS as food, after being torn into the finest 
 shreds, partially digested, and saturated with 
 .the intestinal and urinary secretions, are com- 
 mingled with much earth. This earth forms 
 the dark coloured, rich humus which almost 
 everywhere covers the surface of the land 
 with a fairly well-defined layer or mantle.
 
 314 CONCLUSION. CHAP. VIT. 
 
 Hensen* placed two worms in a vessel 
 18 inches in diameter, which was filled with 
 sand, on which fallen leaves were strewed ; 
 and these were soon dragged into their bur- 
 rows to a depth of 3 inches. After about 
 6 weeks an almost uniform layer of sand, a 
 centimeter (*4 inch) in thickness, was con- 
 verted into humus by having passed through 
 the alimentary canals of these two worms. 
 It is believed by some persons that worm- 
 burrows, which often penetrate the ground 
 almost perpendicularly to a depth of 5 or 6 
 feet, materially aid in its drainage ; notwith- 
 standing that the viscid castings piled over 
 the mouths of the burrows prevent or check 
 the rain-water directly entering them. They 
 allow the air to penetrate deeply into the 
 ground. They also greatly facilitate the 
 downward passage of roots of moderate size ; 
 and these will be nourished by the humus 
 with which the burrows are lined. Many 
 seeds owe their germination to having been 
 covered by castings; and others buried to 
 a considerable depth beneath accumulated 
 castings lie dormant, until at some future 
 
 * ' Zeitschrift fur wissenscbaft. Zoolog.' B. xxviii. 1877, p. 36(X
 
 CHAP. VII. CONCLUSION. 315 
 
 time they are accidentally uncovered and 
 germinate. 
 
 Worms are poorly provided with sense- 
 organs, for they cannot be said to see, 
 although they can just distinguish between 
 light and darkness ; they are completely deaf, 
 and have only a feeble power of smell ; the 
 sense of touch alone is well developed. They 
 can therefore learn but little about the outside 
 world, and it is surprising that they should 
 exhibit some skill in lining their burrows 
 with their castings and with leaves, and in 
 the case of some species in piling up their 
 castings into tower-like constructions. But it 
 is far more surprising that they should ap- 
 parently exhibit some degree of intelligence 
 instead of a mere blind instinctive impulse, in 
 their manner of plugging up the mouths of 
 their burrows. They act in nearly the same 
 manner as would a man, who had to close a 
 cylindrical tube with different kinds of leaves, 
 petioles, triangles of paper, &c., for they 
 commonly seize such objects by their pointed 
 ends. But with thin objects a certain number 
 are drawn in by their broader ends. They do 
 not act in the same unvarying manner in all
 
 .316 CONCLUSION. CHAP. VII. 
 
 cases, as do most of the lower animals; for 
 instance, they do not drag in leaves by their 
 foot-stalks, unless the basal part of the blade 
 is as narrow as the apex, or narrower than it. 
 
 When we behold a wide, turf-covered 
 -expanse, we should remember that its smooth- 
 ness, on which so much of its beauty depends, 
 is mainly due to all the inequalities having 
 been slowly levelled by worms. It is a mar- 
 vellous reflection that the whole of the super- 
 ficial mould over any such expanse has passed, 
 and will again pass, every few years through 
 the bodies of worms. The plough is one of 
 the most ancient and most valuable of man's 
 inventions; but long before he existed the 
 land was in fact regularly ploughed, and still 
 continues to be thus ploughed by earth-worms. 
 It may be doubted whether there are many 
 other animals which have played so important 
 ;a part in the history of the world, as have 
 these lowly organised creatures. Some other 
 animals, however, still more lowly organised, 
 namely corals, have done far more conspicuous 
 work in having constructed innumerable reefs 
 and islands in the great oceans ; but these are 
 almost confined to the tropical zones-.
 
 INDEX. 
 
 Abinger, Eoman villa at, 180 
 
 , castings from Eoman villa at, with rounded 
 
 particles, 256 
 
 Acids of humus, action on rocks, 242 
 Africa, dust from, 237 
 Air, currents of, worms sensitive to, 29 
 Amount of earth brought to the surface by worms, 131 
 Ants, intelligence of, 95 
 Archiac, D', criticisms on my views, 4 
 Artemisia, leaves of, not eaten by worms, 34 
 Ash-tree, petioles of, 81 
 
 Beaulieu Abbey, burial of the old pavement, 195 
 , castings from, with rounded particles, 
 
 258 
 
 Beaumont, Elie de, on vegetable mould, 2 
 ' on the rubbish underlying great cities, 
 
 180 
 
 on the transport of dust, 239 
 
 on the permanence of mould, 292 
 
 on the permanence of ancient tumuli, 
 
 293 
 
 Beech-forests, stones not buried under by castings, 146 
 Bengal, worms of, 125 
 Boa-constrictor lubricating its prey, 44 
 Bones, crushed, burial of, under castings, 148 
 JBrading, Koman villa at^201
 
 318 INDEX. 
 
 Brading, castings from, with rounded particles, 257 
 Bridgman, Mr., on worms eating leaves of a Phlox, 34 
 Buckman on grasses profiting by being rolled, 10 
 Burial of the remains of ancient buildings by worms,, 
 
 178 
 Burrows, depth of, 111 
 
 direction of, on a slope, 273 
 
 excavation of, 100 
 
 lined with black earth, 113 
 
 lined with leaves, 114 
 
 mouths of, worms lie motionless near, 15 
 
 old, their collapse, 120 
 
 plugged up, 60 
 
 terminating in a small chamber, often lined with, 
 
 stones or seeds, 116 
 
 Calciferous glands, 17, 45 
 Cannibal worms, 37 
 Carabus attacking worms, 65 
 Carnagie, Mr., depth of burrows, 116 
 Castings, acid, 53 
 
 from Beaulieu, 103 
 
 in cellars, 107 
 
 tower-like, near Nice, 108 
 
 ejection of, 118 
 
 tower-like, from near Calcutta, 125 
 
 of great size on the Nilgiri Mountains, 128 
 
 weight of, from a single burrow and from a given 
 
 area, 163 
 
 thickness of layer formed from, during a year, 171 
 
 ejected over ancient buildings, 256 
 
 flowing down slopes, 264 
 
 washed away, 275 
 
 dry, disintegration of, 278 
 
 blown to leeward, 286
 
 INDEX. 319 
 
 Cellars, castings in, 107 
 
 Cells, free, with calcareous matter in the calciferous 
 
 glands, 48 
 
 Cellulose, digestion of, 38 
 Chalk-formation, surface of, much denuded, 139 
 Chalk, residue of, forming a superficial deposit, 140 
 
 fragments of, soon buried and corroded, 141 
 
 formation of mould over, 300 
 
 Ched worth, Roman villa of, 199 
 
 Circular trenches near Stonehenge, 290 
 
 Claparede on the structure of the intestines of worms, 19 
 
 on the salivary glands of worms, 44 
 
 on the calciferous glands, 45 
 
 on the pharynx adapted for suction, 58 
 
 doubts whether earth serves worms as food, 
 
 104, 107 
 
 on the gizzards of worms, 249 
 
 Clematis, petioles of, used in plugging up burrows, 60, 
 
 80 
 
 Cobra-snake, intelligence of, 96 
 Collapsing of old burrows, 120 
 Concluding remarks, 308 
 Concretions of lime in the anterior calciferous glands, 47 
 
 calcareous, use of, 55 
 
 Corals, mud derived from, 259 
 
 Corniche road, disintegrated castings on, 279, 284 
 
 Croll, Mr., on denudation, 235 
 
 Crowns or ridges on old ploughed fields, 295 
 
 Currents of air, worms sensitive to, 29 
 
 Dancer, Mr., on the action and number of worms, 148, 
 
 162 
 
 Deafness of worms, 26 
 
 Debris over the Roman remains at Silchester, 203 
 Decay of leaves not hastened by the secretion with which 
 
 they are bathed, 39
 
 320 INDEX. 
 
 Denudation of the land, 232 
 Depth to which worms burrow, 111 
 Digaster, 249 
 Digestion of worms, 38 
 
 extra-stomachal, 44 
 
 Disintegration of rocks aided by worms, 238 
 
 Distribution of worms, 122 
 
 Down, amount of earth here brought annually to the- 
 
 surface, 139 
 
 Downs near Winchester, valleys in, 304 
 Dust, distance transported, 237-239 
 
 Earth, amount of, brought to the surface by worms, 
 131 
 
 amount of, which flows down a given slope, 269 
 
 swallowed as food, 102 
 
 weight of, ejected from a single burrow, 163 
 
 Eisen on the number of species of worms, 9 
 
 on the depth of burrows, 112 
 
 Ejection of castings, 118 
 Embankments on hill-sides, 281, 285 
 Encampments, ancient, 293 
 Ernst, Dr., on worms at Caracas, 123 
 Excavation of the burrows, 100 
 
 Fabre, M., on the instincts 'of Sphex, 95 
 
 Farrer, Mr. T. H., on the Roman villa at Abinger, 
 
 180-190 
 
 Fat eaten by worms, 38 
 Fields formerly ploughed, 295 
 Fish, Mr., criticisms on my views, 6 
 Flints standing vertically in the residue over the chalk, 
 
 140 
 acted on externally and internally by atmospheric 
 
 agencies, 248
 
 INDEX. 321 
 
 Flowing down of castings, 264 
 Fluid, digestive, of worms, 38 
 Food of worms, leaves, 36 
 
 earth, 102 
 
 Foster, Michael, on the pancreatic ferment, 38 
 on the acidity of the contents of tliO' 
 
 intestines, 53 
 Foundations, deep, of the Eoman buildings at Wroxeter, 
 
 229 
 
 Fredericq, Leon, on the digestive juice of worms, 38 
 Furrows on old ploughed fields, 295 
 
 Galton, Mr., on the number of dead worms, 14 
 Geikie, Archibald, on Denudation, 235 
 
 controverts ~E. de Beaumont's views on 
 
 Denudation, 292 
 
 , James, controverts Kichthofen's views, 239 
 
 on glaciated rocks, 248 
 
 Geographical distribution of worms, 122 
 
 Gilbert, Dr., on the amount of nitrogen in worm-castings,, 
 
 244 
 
 Gizzards of worms, 249 
 Glands, calciferous, 17, 45 
 
 function of, 50 
 
 Glen Boy, evidence of rarity of debacles, 263 
 
 Haast, Von, on aboriginal instruments in New Zealand 
 
 found buried, 150 
 Hearing, sense of, 26 
 Heat, perception of, 25 
 Heaths, inhabited by few worms, except where patb 
 
 cross them, 10 
 Hensen on the number of worms in gardens, 5 
 
 on worms not subsisting on earth, 110 
 
 on the depth of burrows, 112
 
 322 INDEX. 
 
 Hensen on number of worms living in a given area, 161 
 
 on the composition of mould, 240 
 
 on the amount of humus formed by two 
 
 worms, 314 
 
 Henslow, Prof., on ledges on hill-sides, 281 
 Hoffmeister, number of species of worms, 9 
 
 on worms hybernating in company, 35 
 
 perception of light by worms, 20, 22 
 
 on the enemies of worms, 65 
 
 depth of burrows, 112 
 
 on hybernation of worms, 116 
 
 Hooker, Sir J., on ledges of earth on the Himalaya, 281 
 Horner, Mr., on castings in a cellar, 108 
 Humus acids, action of, on rocks, 242, 247 
 
 Instinct of worms, 36 
 Intelligence of worms, 36, 66 
 Intestines of worms, their contents acid, 52 
 Islands inhabited by worms, 122 
 
 Johnson, Dr. H., on the Roman remains at Wroxeter, 
 224-230 
 
 on ammonia in worm-castings, 244 
 
 Johnson, S. W., * How Crops Feed,' 244 
 Joyce, Rev. J. G., on the Roman remains at Silchester, 203 
 Julien, Mr. A. A., on the composition of peat, 240 
 on the humus-acids, 242, 247 
 
 Key, Rev. H., on the burial of cinders by worms, 148 
 King, Dr., on the formation of mould in forests in 
 
 France, 5 
 
 on castings near Nice, 108, 119 
 
 on great castings on the Nilgiri Mountains 
 
 and in Ceylon, 128 
 weight of castings near Nice, 165
 
 INDEX. 323 
 
 King, Dr., on disintegrated castings on the Corniche 
 
 road, 279, 284 
 on the washing away of the castings on the 
 
 Nilgiri Mountains, 277 
 
 Knole Park beech- woods, worms absent from, 12 
 Koninck, De, on the disintegration of rocks, 237 
 Krukenberg on the digestive fluid of worms, 38 
 
 Laburnum leaves, 70 
 
 Land, denudation of, 232 
 
 Lankester, Bay, on the structure of worms, 18 
 
 on worms from Kerguelen Land 123 
 
 La Plata, dust storms of, 238 
 
 Layard,Mr., on the habits of the cobra, 96 
 
 Leaves, worms distinguish the taste of different kinds of, 33 
 
 consumed by worms, 36 
 
 their decay not hastened by the alkaline secretion 
 
 with which they are bathed, 39 
 
 decayed, generate acids, 52 
 
 used in plugging up burrows, 67 
 
 used to line burrows, 114 
 
 Ledges of earth on hill-sides, 281 
 Light, perception of, by worms, 20 
 Lime, carbonate of, concretions of, 46 
 
 Maer Hall, amount of earth brought to surface, 132 
 Mallett, Mr., on the sinking of the ground under great 
 
 buildings, 161 
 
 Meat, raw, eaten by worms, 37 
 Mental qualities of worms, 34 
 Mint, leaves of, only nibbled, 34 
 Mississippi, drainage area of, 235 
 Moles pursuing worms, 28 
 Mobius on the habits of a pike, 96 
 Moniligaster, 249
 
 324 INDEX. 
 
 Moot-house, Mr., on peewits beating the ground, 28 
 
 JVIorren on worms surviving long immersion, 13 
 
 OH worms lying motionless near mouths of their 
 
 burrows, 15 
 
 on worms eating sugar, 37 
 
 on the disappearance of the calciferous glands 
 
 during winter, 50 
 
 on stones in the gizzards of worms, 250, 252 
 
 Mould, thickness of, annually ejected by worms, 171 
 thickness of, over Eoman remains at Chedworth. 
 
 201 
 
 nature and thickness of, over the Roman remains 
 
 at Silchester, 220 
 
 thickness of, at Wroxeter, 225 
 
 formation and thickness of, over the chalk, 800 
 
 Mountains, worms absent from, 12 
 
 Miiller, Fritz, on the worms in South Brazil, 124 
 
 Miiller, P. E., on earthworms, p. 7. 
 
 Nice, castings near, 108 
 
 disintegrated castings near, 279 
 
 Night, worms leave their burrows at, 14 
 Nilgiri Mountains, castings on, 128 
 
 Objects strewed on the surface soon buried under cast- 
 ings, 132 
 
 Obliteration of old furrows on ploughed land, 295 
 Odours, degree of sensitiveness to, by worms, 30 
 
 Pancreatic secretion, 38 
 
 not acid, 54 
 
 Paper, triangles of, 85 
 
 Parfitt, Mr., on the closing of the mouths of burrows, 65 
 
 Path, paved, burial of, by worm-castings, 147 
 
 Paths inhabited by worms, 10 
 
 Pavement, modern, undermined by worms, 194
 
 INDEX. 325 
 
 Pavements, ancient, subsidence of, at Sil Chester, 214 
 Peat, formation of, 241 
 Peewits beating the ground, 28 
 Percolation of earth into the chalk, 300 
 PerichsBta, naturalized near Nice, 108 
 Perrier, worms surviving long immersion, 13 
 
 on the calciferous glands, 45 
 
 on the action of the pharynx, 58 
 
 on the burrowing power of worms, 101 
 
 on naturalized worms, 108 
 
 on worms killed by acetic acid, 162 
 
 on the gizzards of worms, 249, 252 
 
 Petioles of Clematis, 80 
 
 of the ash, 81 
 
 Pharynx, action of, 58 
 
 Pike, stupidity of, 96 
 
 Pine-leaves used in plugging up burrows, 61, 73 
 
 lining burrows, 114 
 
 Pipes, formation of, in the chalk, 139 
 Playfair on Denudation, 293 
 Ploughed fields, old, 295 
 Plugging up of the burrows, 60 
 
 use of the process, 64 
 
 Prehension, power of, by worms, 58 
 
 Qualities, mental, of worms, 34 
 
 Eamsay, Mr., on the sinking of a pavement undemined by 
 worms, 194 
 
 on Denudation, 233 
 
 Eemains, ancient, buried by worms, 178 
 
 Rhododendron leaves, 71 
 
 Richthofen on dust deposits in China, 239 
 
 Robinia, petioles of, 83 
 
 Rocks, disintegration of, aided by worms, 238
 
 326 INDEX. 
 
 Rocks, triturated in the gizzards of worms, 252 
 
 Rolling down of dry castings, 278 
 
 Romanes, Mr., on the intelligence of animals, 97 
 
 Sachs on living roots corroding rocks, 245 
 
 Sage, leaves of, not eaten by worms, 34 
 
 Saliva, doubtful whether any secreted by worms, 44- 
 
 Saussure, H. de, on brick-pebbles, 257 
 
 Schmulewitsch on the digestion of cellulose, 39 
 
 Scolopendra attacking worms, 65 
 
 Scott, Mr. J., on worms near Calcutta, 125 
 
 Seeds preserved in the burrows of worms, 117 
 
 Semper on various animals swallowing sand, 104 
 
 Senses of worms, 19 
 
 Silchester, old Roman town, 203 
 
 Silica, colloid, acted on by the humus-acids, 244 
 
 Simpson, Mr., on worms dragging leaves, 60 
 
 Sinking of the pavements at Silchester, 214 
 
 Sites inhabited by worms, 9 
 
 Smell, sense of, 29 
 
 Social feelings of worms, 35 
 
 Sorby, Mr., on the trituration of small particles of 
 
 rock, 260 
 
 Stanley on peewits beating the ground, 28 
 Starch eaten by worms, 37 
 digestion of the granules in the cells of leaves, 
 
 43 
 
 St. Catherine's Hill, near Winchester, 305 
 Stones, great, undermined by worms at Leith Hill and at 
 
 Stonehenge, 151 
 
 small, heaped over burrows, 63 
 
 small, in the gizzards of worms, 250 
 
 rounded in the gizzards of worms, 252 
 
 Stonehenge, great stones of, undermined by worms, 157 
 circular trenches near, 290
 
 INDEX. 327 
 
 Structure of worms, 16 
 
 Sturtevaiit, Dr., on worms found coiled together, 35 
 
 Subsidence of the pavements at Silchester, 214 
 
 Suction, power of, 58 
 
 Sugar eaten by worms, 37 
 
 Summary of whole book, 308 
 
 Surface, objects strewed on, buried under castings, 132 
 
 Taste, power of, 33 
 
 Thickness of the layer of mould annually ejected by 
 
 worms, 171 
 
 of the mould over the remains at Chedworth, 201 
 
 of the mould over the remains at Silchester, 220 
 
 of the mould over the Roman remains at 
 
 Wroxeter, 225 
 
 Thyme, leaves of, not eaten by worms, 34 
 Touch, worms highly sensitive to, 29 
 Triangles of paper, 85 
 Trituration of particles of rock in the gizzards of worms, 
 
 252 
 
 Tumuli, ancient, 293 
 Tylor, Mr. A., on Denudation, 235 
 Tylor, Mr. E., on anciently ploughed land, 296 
 Typhlosolis, 19 
 
 Utricularia, bladders of, 111 
 
 Vibrations, worms sensitive to, 27 
 Vision, power of, in worms, 20 
 
 Wallace, Mr. J., on worm-burrows, p. 270. 
 
 Walls, ancient, at Abinger, penetrated by worms, 190 
 
 penetrated by worms at Silchester, 211 
 
 Washing away of castings, 275 
 
 Wedgwood, Mr., on the formation of mould, 3
 
 328 INDEX. 
 
 Weight of earth ejected from a single burrow, 163 
 
 Whitaker, Mr., on Denudation, 234 
 
 White on worms leaving their burrows at night, 14 
 
 Winchester, chalk formation near, 304 
 
 Wind, action of, on castings, 286 
 
 Worms, nocturnal, 13 
 
 large numbers occasionally die, 14 
 
 dead eaten by other worms, 34 
 
 contents of intestines acid, 52 
 
 their castings acid, 53 
 
 power of suction, 58 
 
 plugging up their burrows, 60 
 
 intelligence of, 66 
 
 formation of their burrows, 100 
 
 number of, living in a given area, 161 
 
 penetrating ancient walls, 190, 211 
 
 gizzards of, and the trituration of the contained 
 
 stones, 249 
 
 prefer to live in fine earth, 294 
 
 Wright, Mr., on the age of Wroxeter, 223 
 Wroxeter, old Roman town of, 223 
 
 Zincke, Rev. F. B.. on celts found at a depth of thrco 
 feet, 148 
 
 PRINTED BY WILLIAM CLOWES AND SONS, LIMITED 
 STAMFOBD STREET AND ClUEINO CBOSS.
 
 Date Due 
 
 MAY 2 
 
 31972 
 
 CAT. NO. 23 233 PRINTED IN U.S.A.
 
 REGIONAL LIBRARY FACILITY 
 
 A 000500919 6 
 
 QH365 
 .Al 
 
 1897 
 Darwir . 
 
 The formation of vegetable mould, 
 
 CALIFORNIA COLLEGE OF MEDICINE LIBRARY 
 
 UNIVERSITY OF CALIFORNIA, IRVINE 
 
 IRVINE, CALIFORNIA 92664