-NRLF 313 THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BY PROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID PALEONTOLOGY LIBRARY II y a eu une epoque ou notre planete ne possedait aucun germe de vie organised ; done la vie organisee y a commence sans germe anterieur. Toutes les apparitions nouvelles qui ont eu lieu dans le monde se sont faites, non par 1'acte incessamment renouvele d'un Etre Createur, mais par la force intime deposee une fois pour toutes au sein des choses." Ernest Renan. ' The utmost possibility for us is an interpretation of the process of things as it presents itself to our limited consciousness. . . . There is no mode of establishing the validity of any belief except that of showing its entire congruity with all other beliefs.' Herbert Spencer. THE BEGINNINGS OF LIFE BEING SOME ACCOUNT OF THE NATURE, MODES OF ORIGIN AND TRANSFORMATIONS OF LOWER ORGANISMS. H. CHARLTON BASTIAN, M. A., M. D., F. R. S. Fellow of the Royal College of Physicians ; Professor of Pathological Anatomy in University College, London; Physician to University College Hospital; Assistant Physician to the National Hospital for the Paralysed and Epilefiic. IN TWO VOLUMES. VOL. I. WITH NUMEROUS ILLUSTRATIONS. 0rk D. APPLETON AND CO. 1872. WTONTOLOGY LIBRARY Gift of C. A. Kofoid OXFORD: By T. Combe, M.A., E. B. Gardner, E. Pickard Hall, and J. H. Stacy. PRINTERS TO THE UNIVERSITY. Q-H- 3*5" P RE FAC E. RATHER more than three years ago, in the course of some investigations upon the microscopical characters of the blood of persons suffering from acute diseases, my attention was first thoroughly given to the great question of the Origin of Life. And as so much depended upon the proper solution of this problem not only for Science generally, but even with reference to the scientific basis of Medicine I deter- mined to undertake some investigations and endeavour to revise the grounds of opinion upon the subject. I did investigate, and in consequence was after a time compelled to renounce my old prepossessions, and adopt views concerning the origin of c living' matter which are as yet only very partially accepted in the world of science. The state of professional opinion on these questions, moreover, was such that it would have been unsuitable for me to have taught new doctrines based upon facts ascertained during these investigations, without having fully and publicly stated the grounds upon which I had adopted them. At much personal sacrifice, therefore, I resolved to attempt to produce a statement of the facts which should carry conviction to the minds of others. And VOL. i. b vi PREFACE. although at first wishing to do this in a work much smaller than that which I now submit to the public, it was soon found that more elaboration would be needed. The scope of the subject itself, moreover, widened so rapidly biological problems of such enormous import- ance were opened up that I at last felt compelled to pursue the investigation in a manner a little more com- mensurate with the magnitude of its dependent issues. The First Part of this work was written and printed nearly three years ago. It was intended to show the general reader, more especially, that the logical conse- quences of the now commonly accepted doctrines con- cerning the 'Conservation of Energy' and the c Cor- relation of the Vital and Physical Forces/ were wholly favourable to the possibility of the independent origin of c living ' matter. It also contains a review of the 'Cellular Theory of Organization/ which was written and was in type before I had had the pleasure of reading Prof. Strieker's essay on c Cells.' In the Second Part of the work, under the head c Archebiosis/ the question as to the present occurrence or non-occurrence of f spontaneous generation ' is fully considered. And in spite of all the difficulties in great part imaginary which have hitherto interfered with the acceptance of a positive solution of this problem, it seems to me one which is now not difficult to solve. It must be considered to turn almost wholly upon the possibility of the de novo origin of Bacteria ; since if such a mode of origin can be proved for them, it must also be conceded for other allied fungoid and algoid units. Evidence which is of the most convincing character when looked at from all sides, now shows PREFACE. vii that Bacteria are killed by a temperature of i4OF. Yet similar organisms will constantly appear and rapidly multiply within closed flasks containing organic fluids, although the flasks and their contents have been pre- viously exposed for some time to a temperature of 2i2F. The latter fact has been admitted by almost all experimenters including even Spallanzani and Pasteur and the inference from it must be quite obvious to those who accept this or any lower tem- perature as the thermal limit of organic life. In experi- ments yielding positive results, they would have to admit that the progenitors of the new, and more or less rapidly multiplying brood must have been evolved de novo within the previously superheated flasks. So that, even if nothing more could be said, the positive results which can almost invariably be obtained in experiments conducted with this temperature, should suffice, in the present state of science, to show that living matter may arise de novo more especially when such a conclusion is also supported by the utter break-down of the opposing Panspermic hypothesis. But much stronger evidence can be adduced ; since numerous similarly successful results have been obtained by Pasteur himself, by Pouchet, Mantegazza, Wyman, Cantoni, Oehl, and others although the closed flasks and their contents had been subjected to the influence of still more destructive tem- peratures, ranging from 212 F to rather over 300 F. Several of such experiments are now recorded for the first time ; and their results cannot be reasonably ex- plained except on the supposition that the living things obtained from the closed flasks had been developed from newly-evolved living matter. viii PREFACE. The probabilities in favour of this interpretation of the experimental evidence become, moreover, stronger and stronger in proportion as the problem is viewed by the light derived from various kinds of general evi- dence, which I have adduced in different parts of this work. We know that the molecules of elementary or mineral substances combine to form acids and bases by virtue of their own c inherent' tendencies; that these acids and bases unite so as to produce salts, which, in their turn, will often again combine and give rise to c double salts/ And at each stage in this series of ascending molecular complexities, we find the products endowed with properties wholly different from those of their con- stituents. Similarly, amongst the carbon compounds there is abundance of evidence to prove the existence of internal tendencies or molecular properties, which may and do lead to the evolution of more and more complex chemical compounds. And it is such synthetic processes, occurring amongst the molecules of colloidal and allied substances, which seem so often to engender or give c origin' to a kind of matter possessing that subtle combination of properties to which we are accustomed to apply the epithet c living. 5 The experimental evidence which I have brought forward not only goes to prove that living matter may originate in this natural manner, but that, like other kinds of matter, it comes into being by virtue of the operation of the same laws and molecular properties as suffice to regulate its c growth/ Would it not be deemed absurd if we were to assume, as a necessity, the existence of one set of agencies in order to bring PREFACE. ix about the origination of crystalline matter, and of another set for inducing and regulating the growth of crystals ? And may it not also be deemed just as absurd and unnecessary that any such demands should be made in reference to the origin of living matter and the growth of organisms? Both crystalline and living aggregates appear to be constantly separating de novo from different fluids, and both kinds of matter now seem to be naturally formable from their elements. It so happens, however, that one of the fundamental properties of living matter that is to say, its power of undergoing spontaneous division is constantly entailing results which, owing to their being of a more obvious nature, have long and unduly monopolized the attention of biologists and of the world in general. And yet the existence in living matter of this power of spontaneous division, by which processes of c reproduction ' are brought about, is rendered somewhat less exceptional and mysterious when we consider that a fragment of crystalline matter artificially severed from the parent mass will, under suitable con- ditions, grow into a crystal similar to the original form. The reproduction of similar matter takes place in each case ; and surely the mere fact that the initial repro- ductive separation may occur c spontaneously ' in the case of living matter, is no argument against the pro- bability that such matter may, like crystalline matter, also come into being by an independent elemental mode of origin. Our experimental evidence, therefore, merely goes to prove that such an elemental origin of living matter is continually taking place at the present day, that PREFACE. it still comes into being, in fact, by the operation of the same laws, and in the same manner as the majority of scientific men and a large section of the educated public believe that it must have originated in the early days of the earth's history when c living' compounds first began to appear upon the cooling surface of our planet. And if such synthetic processes took place then, why should they not take place now ? Why should the inherent molecular properties of various kinds of matter have undergone so much alteration ? Why should these particular processes of synthesis now be impossible, although other processes of a similar nature still go on? Whilst no attempt has ever been made to justify or explain such a supposed arbitrary curtailment of natural laws, it happens most fortunately that the ascending series of molecular combinations, to which we have already referred, does not end with the birth of c living ' matter. Steps which were previously beyond the reach of our senses, become, in some newly-dis- covered terms of the series, capable of ocular demon- stration. Whilst invisible colloidal molecules are sup- posed to combine and undergo re-arrangements in order to produce specks of new-born living matter, such specks of living matter may be actually seen to com- bine, fuse, and undergo molecular re-arrangements so as to lead to the origin of Fungus-germs, of Amoebse, of Monads, or of Ciliated Infusoria ; and, in the same manner, larger and still more complex living units of an algoid nature may actually be seen to fuse and become altered externally, whilst they undergo those obscure and mysterious molecular re-arrangements PREFACE. xi whereby they are converted into the embryos of large and complex Rotifers. Visible phenomena of Synthetic Heterogenesis thus serve, as it were, to demonstrate the mode in which, by invisible processes, the simplest living units may arise. So that after watching all the steps of the more complex phenomena, we may find it less difficult than we should otherwise have done to believe in the occur- rence of the simpler process of Archebiosis more espe- cially when its occurrence is attested by facts and probabilities of the highest independent value. Again, we know that simple mineral substances may exist in different allotropic conditions, just as numeri- cally-similar combinations of different elements may exist in two or more isomeric states. But, if mere differences in molecular arrangement may cause sulphur or arsenic, on different occasions, to present wholly different appearances and properties; or if a similar alteration in molecular arrangement may lead such salts as mercuric iodide to pass easily from one to another mode of crystallization, it should not be very difficult for us to believe that living matter might also, with comparative ease, undergo somewhat analogous mole- cular rearrangements, and that such changes might also entail some modifications in the form and other attributes of the living aggregate. And now, as matter of fact, we have to state that the occurrence of Hetero- genetic Transformations amongst lower living things and in portions of higher living things have been almost as well attested as the occurrence of allotropic and isomeric modifications amongst different kinds of not-living matter. xii PREFACE. Unmistakeable processes of Heterogenesis have been watched over and over again by some of the best ob- servers, amongst whom may be named Turpin, Kiitzing, Reissek, Hartig, Gros, Pringsheim, Pineau, Carter, Nicolet, Pouchet, Schaaffhausen, Braxton Hicks, and Trecul. And yet the careful investigations of these well-known naturalists have, upon this particular sub- ject, been either wholly disregarded or publicly repudiated by some leading biologists who not having worked over the same ground themselves rashly trust to their own theoretical convictions, rather than to the positive observations of so many workers. How un- warrantable this conduct has been, almost any compe- tent person however sceptical may learn for himself, if he will but devote two or three months to the careful study of the changes which are apt to take place in the substance of many of the fresh-water Algae, or in those beautiful green animalized organisms known by the name of Euglenae, some of whose marvellous trans- formations were faithfully described more than twenty years ago in the highly valuble but much neglected memoir of Dr. Gros. The time is doubtless not far distant when it will be a source of much wonder that those who had already heartily adopted the Evolution philosophy could even in the face of facts long ago known stop short of a belief in the present and continual occurrence of Arche- biosis and Heterogenesis. Do not the very simplest forms of life abound at the present day ? And, would the Evolutionist really have us believe that such forms are direct continuations of an equally structureless matter PREFACE. Xlll which has existed for millions and millions of years without having undergone any differentiation ? Would he have us believe that the simplest and most struc- tureless Amoeba of the present day can boast of a line of ancestors stretching back to such far-remote periods that in comparison with them the primseval men were but as things of yesterday? The notion surely is preposterously absurd; or, if true, the fact would be sufficient to overthrow the very first principles of their own Evolution philosophy. Again, may we not see at the present day all those minute shades of difference by which the primordial fissiparous act of reproduction gives place to the more and more specialized forms of bisexual reproduction? Even this could scarcely occur unless the excessively changeable forms of life which supply us with these various transitions were continually seething into existence afresh. Instead of having to do with a pretty accurate picture of the original process of evolution, each sectional mosaic of which has been faithfully transmitted for millions of years with little or no variation, we probably stand face to face with processes that have been independently repeated billions and billions of times and repeated in a more or less similar manner, simply because the processes themselves have always been the results of the conjoint action of the same external forces in conflict with similar material properties or tendencies. Like causes should produce like results: so that the primordial living units of to-day should undergo changes which are, in the main, similar to those passed through by the units of living matter which first came into being upon the surface of our globe. xiv PREFACE. Again, we find that the comparatively low forms of life in which all these developmental transitions are embodied, instead of being almost unchangeable as they ought to be if there were any truth in the con- tradictory doctrines to which we have already referred are variable in the highest degree. They pass through the most diverse and astounding transformations, and, as we have endeavoured to show in the Third Part of this work, such organisms are often seen to be derived from matrices wholly unlike themselves. In fact, these lower forms of life corresponding pretty closely with the Protista of Prof. Haeckel form an enormous and ever-growing plexus of vegetal and animal organisms, amongst which transitions from the one to the other mode of growth take place with the greatest ease and frequency. Here Heterogenesis is constantly encountered, and variability reigns supreme, so that those assemblages of definitely recurring indi- viduals, answering to what we call c species/ are not to be found amongst them. They are essentially tran- sitory and variable forms, which I have proposed to name c Ephemeromorphs/ Regularly recurring or homo- genetically produced types, both animal and vegetal, are, however, constantly arising out of this great ephe- meromorphic plexus, either by direct and sudden pro- cesses of transformation or by some intermediate and cyclical processes of so-called ' alternate generation.' And until such assemblages of repeating individuals make their appearance that is, until Homogenesis becomes the rule the c laws of heredity' can scarcely be said to come into operation. Hence the complexly- interrelated individuals, constituting this vast under- PREFACE. XV lying plexus of Infusorial and Cryptogamic life, must remain wholly uninfluenced, so far as their form and structure is concerned, by what Mr. Darwin has termed c Natural Selection.' Such vegetal and animal organisms, however, gradually tend to become more and more complex. An ascending development takes place, and as this occurs, the causes which originally sufficed to determine their form and structure, and which for a time continue to induce deviations, become less and less capable of bringing about structural modifications during the life of the individual. Changes have now to be perfected in a succession of individuals; and thus is the operation initiated of those subtle and more slowly modifying agencies which have been so admirably illustrated by Mr. Darwin. Throughout this work, whilst I have been anxious to consider the various aspects of the subject with as much thoroughness as was necessary in order to be able fairly to attempt to establish the truth of the principal doctrines now advanced, I have also tried to simplify the problems as much as possible. A limitation was, moreover, necessitated by the pressing nature of those more strictly professional duties, on account of which I was first induced to enter upon these investigations, and in the midst of which the work has been carried on. A rich harvest, therefore, remains for many other workers who may wish to develop the subject in all its collateral bearings. These volumes being, in great part, the record of a series of current investigations each section of which was written whilst the next division of the subject was xvi PREFACE. being investigated some forbearance may, perhaps, not unfairly be claimed for certain literary defects and in- consistencies, which were to some extent unavoidable. For although this order was definitely planned, yet it has happened that more than three-fourths of the work was actually printed before the new investigations de- tailed in the latter part were made and certainly at a time when I had scarcely hoped ever to witness such transformations as I have since been able to follow. I am deeply impressed with the conviction that we are but upon the threshold of our acquaintance with these marvellous heterogenetic transformations, the discovery of which already affords material for revolu- tionizing the old foundations of botanical and zoological science. But the path now opened must be followed up by other workers by faithful and competent ob- servers who are willing zealously to watch and wait through eager hours whilst Nature unfolds her secret processes by those true students who, instead of being blinded by any existing theories, are content to regard them as useful and modifiable aids to further progress. QUEEN ANNE STREET, CAVENDISH SQUARE, May 22, 1872. CONTENTS. Index .. .. .. .. .. .. .. page xx i PART I. The Nature and Source of the Vital Forces, and of Organizable Matter. CHAPTER I. Pages The Persistence of Force : Correlation of the Vital and Physical Forces 1-49 CHAPTER II. The 'Vital Principle': Nature of Life .. .. .. 5O~79 CHAPTER III. Nature of Organizable Materials and of lowest Living Things 80-128 CHAPTER IV. Relations of Animal, Vegetable, and Mineral Kingdoms : Theories of Organization .. .. .. .. 129-168 CHAPTER V. Modes of Origin of Reproductive Units and of Cells .. 169-239 xviii CONTENTS. PART II. Archebiosis. CHAPTER VI. Pages Meanings attached to term 'Spontaneous Generation' .. 243-264 CHAPTER VII. Mode of Origin of Primordial Living Things: Nature of Problem 265-395 CHAPTER VIII. The Limits of ' Vital Resistance ' to Heat . . - . . . . 306-343 CHAPTER IX. The Experimental Proof: Untenability of Pasteur's Con- clusions ... .. 344-399 CHAPTER X. Physical and Vital Theories of Fermentation .. .. 400-427 CHAPTER XI. Additional Proofs of the Occurrence of Archebiosis .. 428-475 LIST OF ILLUSTRATIONS. Fig. Page 1. Animals found in tufts of Moss and Lichen .. .. 106 2. Hydra viridis on Duckweed (Roesel) .. .. 112 3. Representatives of Monera (Haeckel) .. .. .. 119 4. Animal Cells (Kolliker) M5 5. Unicellular Organisms 152 6. Formation of Spore in Vaucheria (Hassall) .. .. 174 7. Development of Zoospores in Achlya (linger) .. .. 180 8. Development of Spores in Ascomycetous Fungi (Corda) 183 9. Development of 'Cells' in internodes of Chara (Carter) 187 10. Reproduction of Protomyxa (Haeckel) 194 11. Development of Reproductive Units in Amoeba (Nicolet) 198 12. Early Forms of Ova in Ascaris mystax (A. Thomson) .. 201 13. Graafian Follicles of a Mammal (Coste) 203 14. Portions of the Ovary of the Thrush (A. Thomson) .. 205 15. Segmentation of the Yolk after Fecundation (Kolliker) .. 209 16. Development of white blood-corpuscles 226 17. Some of the Primordial Forms of Life: Bacteria, Torulse, &c 272 1 8. Other Early Forms of Life from Organic Infusions .. 274 19. Oscillatorise and other Simple Fresh-water Algse (Hassall) 276 20. The ' Micrococci ' and ' Cryptococci ' of Hallier . . . . 284 21. Sarcina from Saline Solutions .. .. .. 287 22. Different Developmental Stages of 'Spores' (?) found in an Ammonic Carbonate Solution 290 23. Organisms found in Infusions of Hay with Carbolic Acid 356 XX LIST OF ILLUSTRATIONS. Fig. Page 24. Bacteria, Vibriones, and Leptothrix Filaments found in an Infusion of Turnip .. .. .. .. .. .. 358 25. Organisms found in a Simple Solution of Ferric and Ammonic Citrate . . . . . . . . . . . . 364 26. Organisms found in a Solution of Ferric and Ammonic Citrate, with minute fragments of wood . . . . . . 365 27. Fungus from a Solution of Potash and Ammonia Alum with Tartar-emetic .. .. .. .. .. .. 367 28. Torulse from a Solution of Ammonic Tartrate and Sodic Phosphate .. .. .. .. .. .. .. 369 29. Fungus from a Solution of Ammonic Tartrate and Sodic Phosphate .. .. .. .. .. .. .. 371 30. Organisms from a Neutralized Infusion of Turnip .. 442 31. Protamcebse, Monads, Torulse, &c., from an Infusion of Common Cress .. .. .. .. .. .. 444 32. Torulse from a Neutralized Infusion of Turnip .. .. 447 33. Pediastreae from a Solution containing Iron and Ammonic Citrate, &c 448 34. Green and Colourless Organisms from a Solution of Iron and Ammonic Citrate .. .. .. .. .. 450 35. Greenish, Desmid-like Organisms found in a Fluorescent Solution of Iron and Ammonic Citrate .. .. .. 453 36. Spore-like bodies from a Solution of Ammonic Carbonate and Sodic Phosphate .. .. .. .. .. 462 37. Bacteria and Spore-like bodies found in a Solution of Ammonic Carbonate and Sodic Phosphate .. .. 463 38. Fungus found in a Solution of Ammonic Tartrate and Sodic Phosphate .. .. .. .. .. .. 466 INDEX. {Pages of the Appendix are referred to by Roman Numerals.) ACHLYA, production of zoospores in, i. 179. Acinetee, developmental relation- ships of, xciv. Actinophrys, mode of origin of, ii. 381 ; transformation of Euglenee into, ii. 45 6 ; conversion of, into Ciliated Infusoria, ii. 485 ; sub- sequent development of, ii. 505 ; resolution of Rotifers into, ii. 523; transformation of, into Tardi- grades, ii. 524; into Nematoids, ii. 525. Agardh, on zoospores in Conferva, i. 171. Agassiz, on relation of Ciliata to Planaria, cvii. Air, germs in, ii. 6, 7, 264-288. Algae, transitions between Fungi and, ii. 159; relations of, to Pe- diastreae and Desmids, ii. 160; spores of, ii. 376; interchange- ability of Lichens and, ii. 452; lower, relations of, to Lichens, liii-lviii ; variability of, lix-lxii ; relations of, to Mosses, Ixiii-lxvi ; to Fungi, Ixxvi. Algoid corpuscles, resolution of Euglense into, ii. 4+2 ; transform- ation of, ii. 443 ; origin of Rotifers from, ii. 510. Alternate Generation, ii. 564 ; rela- tions of, to other processes, ii. 566 ; nature and mode of origin of, ii. 570. VOL. I. Ammonic Tartrate, preparation of, xvi ; crystals of, containing germs, xvi; examination of crystals of, xvii ; spores in crystals of, xviii. Amoebae, germ-formation in, i, 197 ; digestion in, ii. 132; interchange- ability of Monads and, ii. 218; encystment of, ii. 22 r; resolu- tion of, into Bacteria, ii. 222; production of, in Moss-radicles, ii. 376; modes of origin of, ii. 381, 388 ; origin of, in Vaucheria, ii. 395 ; in Nitella, ii. 404 ; from Chlorophyll corpuscles, ii. 408 ; transformation of Euglense into, ii. 456 ; formation of, in Pro- tonema, Ixx ; relations of, to Fungi, Ixxix ; to other Infusoria, xc ; relations of, to Actiuophrys, xcv. Amylobacter, origin of, ii. 318; conversion of crystalline mass into, ii. 322. Animal heat, origin of, i. 24 ; in- creased by muscular activity, i. 29 ; increase of, during nerve- activity, i. 40. Animals, functions of, related to those of plants, i. 129; forms of, interchangeable with those of ve- getals, ii. 431, 434. Antiseptic system of treatment in disease, cxxv. Arcellinse, 486 ; transformation of, into Ciliated Infusoria, ii. 487. XX11 INDEX. Archebiosis, meaning of, i. 232, 244; views of vitalists antagonistic to, i. 248 ; theory of, ii. 108 ; experi- ments bearing upon, i. 355-372, 434-468, xxx-lii ; relation of, to other processes, (Table) ii. 545, 546. Arlidge, Dr., on Phytozoa, Ixxxi. Ascarides, development of ova of, i. 200. Astasise, modes of origin of, ii. 390, 392, 420; heterogenetic changes in, ii. 434 ; relations of, to Proto- coccus. Ixxxiii ; Dr. Gros on trans- formations of, Ixxxv. Bacon, Lord, on Heat, i. 6. Bacteria, views concerning modes of origin of, i. 268 ; microscopical examination of, i. 294 ; origin of, compared with that of crystals, i. -298 ; vital resistance of, to heat, i. 317; living in air, ii. 2, 6, 7 ; desiccation of, ii. 3-5 ; different views concerning, ii. 134; varia- tions in development of, ii. 137- 140; relations of, to Torulse, ii. 140-146 ; in pellicle, ii. 207 ; pro- duction of, from Amoebse, ii. 2 2 2 ; from embryonal spheres, ii. 401 ; from Euglense, ii. 442 ; develop- mental tendencies of, xxii. Bacteridia, i. 275. Baer, Von, on development in plants and animals, ii. 125. Barry, De, on Myxogasteres, Ixxix; on development of zoospores in Cystopus, Ixxx. Bathybius, i. 122. Beale, Dr. Lionel, views concerning living units, i. 153-158 ; on germs within cells and tissues, ii. 342 ; Panspermic theory of, ii. 358. Bechamp, M., Bacteria in cells, ii. 342- Beclard, M., on development of heat during muscular activity, i. 29. Bennett, Prof. Hughes, on cellular theory of organization, i. 160, ii. 344 ; cellular crystals, ii. 59. Berkeley, Rev. M. J., on nature of Fungi, ii. 153; on Botrytis in- festans, ii. 341 ; development of mushrooms, ii. 433 ; relations of Fungi to Algse and Lichens, Ixxvi ; variability of Fungi, Ixxvii ; rela- tions of animal and vegetable life, Ixxx. - Biocsenosis, nature of, i. 234, (Table) ii. 545, 546. Biocrasis, ii. 193; nature of, i. 233 ; heterogenetic, ii. 62, (Table) ii. 545. 546. Biodioeresis, nature of, i. 233, (Table) ii. 545, 546. Bioparadosis, nature of, i. 234, (Table) ii. 545, 546- Birds, their specialized organization, ii. 627. Black-death, cxxix. Blood, constituents of, as sources of energy, i. 48 ; heterogenetic changes in, ii. 332 ; (Sang de rate) nature of, ii. 362 ; diseases of, cxii, cxvii. Bonnet, Charles, on Panspermi<=m, i. 259; theories concerning germs, ii. 266. Boussingault, M., on vital forces, i. 21 ; source of nourishment in plants, i. 135. Braun, Alexander, on formation of seed in Phanerogamia, i. 190 ; the cell, i. 216 ; formation of seed-cell in QEdogonium, i. 177. Brebisson, M. de, on origin of Mosses from Conferoe, ii. 454. Brongniart, M. Ad., on succession of life on the earth, i. 137-141. Brownian-movement, i. 318. Buffon, theory of life, ii. 1 74. Burdach, on Heterogeny, i. 246, 261. Calculi, artificial formation of, ii. 60-65. Cancer, non-specific nature of, cxiii, cxvii ; germs of, cxiii ; spread of, cxv; comparable with spread of epidemic diseases, cxviii. INDEX. xxin Cantoni, Professor, experiments of, with superheated flasks, i. 436 ; with bent-neck flasks, ii. 9. Carpenter, Dr., on correlation of forces, i. 18, 21 ; continuity of types of Foraminifera, ii. 104; views of, concerning individual- ity, ii. 553 ; on Foraminifera, ii. 6 1 1 ; epidemic diseases, cliii. Carter, Mr. H. J., on development of gonidial-cell in Characese, 1.187; heterogenetic changes in gonidial- cell, ii. 378 ; transformations in Spirogyra, ii. 387 ; mode of origin of Otostoma, 11.479; transform- ations of Ciliated Infusoria, ii. 497 ; relations of Amoebae to Astasise, Ixxxix. Cells, formation and nature of, i. 144-158; formation of gonidial- cell in Characese, i. 187; inde- pendent origin of, in Phaneroga- mia, i. 190 ; as products of deve- lopment, i. 216; origin of, in Blastemata, i. 220-231 ; another mode of origin of, i. 231 ; hete- rogenetic changes in, ii. 338- 345- Cellular theory, discussion of, i. 143- 168. Chara, M. Nicolet on transforma- tions in filaments of, ii. 474; origin of Ciliated Infusoria from protoplasm of, ii. 478. Characese, on development of goni- dial-cell in, i. 187. (See Nitella.'} Child, Dr., on original evolution of organic life, i. 92 ; experiments on fermentation, 1.416. Chlorococcus vesicles, transforma- tion of, into Oxytricha and Plce- sconia, ii. 467 ; aggregations of, into ' winter-egg ' of Hydatina, ii. 514; relation of, to Lichens, liii; developmental changes of, liv ; production of, from Proto- nema, Ixviii; relation of, to Gleo- capsa. Ixix. Chlorophyll, influence of, in meta- morphic changes, ii. 425. Chlorophyll-corpuscles, of Nitella, transformations of, ii. 407 ; of Euglenae into Enchelys, ii. 410; of Moss-radicles into Monads, ii. 41 1 ; of Vaucheria and Nitella into Desmids, ii. 418. Cholera, Dr. Aitken on, cxxix, cxxxviii. Cienkowski, views concerning Aci- netse and Vorticellre, xciv-xcvi. Ciliated Infusoria, mode of origin of, ii. 238, 288; reproduction of, ii. 290-297 ; relation of, to the pellicle, ii. 299; other influences affecting, ii. 302 ; digestion in, ii. 132 ; direct transformation of Euglense into, ii. 450 ; production of, from Monads and Amcebse, ii. 472 ; origin of, from protoplasm of Chara, ii. 478 ; from animal matrices, ii. 483 ; from eggs of Gasteropods and Rotifers, ii. 488; convertibility of forms of, ii. 492 ; ascending transformations of, ii. 500 ; encystment of, ii. 500 ; va- riations in habitat of, ii. 535 ; varied modes of reproduction of, xcvii-cv; successive forms of, in infusions, cvi ; relations of, to Planaria, cvii. Closterium, production of, from Euglenae, ii. 446. Cobbold, Dr., on Psorosperms, ii. 353- Cohn, Professor, on Bacteria, i. 270; on constitution of Pellicle, i. 278 ; on origin of Empusa. ii. 330 ; ex- periments with Stephanosphsera, Ixxxi ; observations on transform- ations of Protococcus, Ixxxii ; suc- cession of Ciliata in Infusions, cvi. Colloidal matter, bodies emerging from solutions of, ii. 65. Colloids, Professor Graham on dis- tinction between crystalloids and, i. 88 ; properties of, i. 89 ; insta- bility of, i. #6 ; interchangeability of crystalloids and, ii. 38 ; nature of, ii. 52. C 2 XXIV INDEX. Comparative Experiments, bearing upon occurrence of Archebiosis, xxx-lii. Conclusions, ii. 633-640. Confervse, origin of Mosses from, ii. 452- Consciousness, i. 42 ; not co-exten- sive with Mind, i. 43 ; changes in sphere of, i. 44 ; degree of corre- lation with nerve-action, i. 45 ; quantitative value of, i. 46. Contagion, theory of, ii. 360 ; mode in which brought about, cxviii ; early views concerning, cxix. Contagious element, action of, in parasitic diseases, ii. 361-365. Contagiousness, degrees of, cxiv, cxxxv; explanation of, cxlviii. Contractility of muscle, i. 26 ; de- pendent on blood-supply, i. 28. Corda, on Peziza, i. 184. Crystalline matter, causes of differ- ences in form of, ii. 87 ; cellular forms of, ii. 59. Crystalloids, distinction between colloids and, i. 88 ; interchange- ability of states of colloids and, ii. 38. Crystals, origin of, compared with that of lowest organisms, i. 298, ii. 71-85 ; Mr. Rainey on form- ation of modifications of, i. 302 ; formation of, under different con- ditions, ii. 55-65 ; size of, de- pends upon rate of collocation, ii. 69 ; influence of conditions on forms of, ii. 87, 113; development of, ii. 114. Darwin, Dr. Erasmus, views on Or- ganization, ii. 538. Darwin, Mr., on Natural Selection, ii- 57 2 > 576; influence of new conditions upon species, ii. 580, 591 ; not a believer in Progressive Development, ii. 590 ; converti- bility of peach and nectarine, ii. 596, 598 ; Correlated Varia- bility, ii. 601 ; Pangenesis, ii. 603 ; affiliation of existing organisms, ii. 606 ; variability of lower or- ganisms, ii. 607 ; stability of spe- cies through long periods, ii. 609. Davaine, M., on Bacteridia, i. 275 ; observations on Sang de rate, ii. 362. Davy, Sir Humphrey, on Heat, i. 8. Decolonization, process of, in deve- lopment of Nematoids and Roti- fers, ii. 532. Desmids, modes of origin of, ii. 41 2, 416, 418, 443, 446, 451 ; mode of reproduction of, ii. 420 ; converti- bility of, into Diatoms or Algae, ii. 455- Diatoms, origin of, ii. 412, 416, 418, 441, 444, 453 ; mode of reproduc- tion of, ii. 420 ; terminal forms of a divergent series, ii. 455. Diseases of skin, parasitic, ii. 346; blood-changes in, ii. 361 ; nature of, cxi ; causes of, cxi ; of general nature, ii. 360, cxii; of special nature, cxiii. Epidemic, mor- tality from, cix; importance of, ex ; problems as to origin of, ex, cxlv, cli-clv ; nature of, cxvii, cxlix; relations of, to Cancer and Tubercle, cxvii ; spread of, cxviii ; doctrines concerning, influenced by views on Fermentation, ex, cxx, cxlix ; predisposing causes of, cliii ; independent origin of, cliii ; contagious, how related to non- contagious, cxxx ; classification of, cxlvi ; how differing from general parasitic diseases, cxlvii. Distomata, direct development of some, explained, ii. 571. Dumas, M., functions of animals and plants compared, i. 130, 142. Dysentery, cxxxviii. Ehrenberg, on multiplication of In- fusoria, i. 262. Embryonal areas of pellicle, nature and developmental transforma- / N D E X. XXV tions of, ii. 198-254 ; spheres, changes in, ii. 40 r. Empusa, nature of, ii. 330. Entozoa, ii. 309. Ephemeromorphs, nature of, ii. 559 ; relation of, to crystals, ii. 571; not influenced by Natural Selec- tion, ii. 572; causes which regu- late their structure, ii. 600 ; have no long line of ancestors, ii. 606 ; Foraminifera to be included amongst, ii. 613. Epochs, Geological, forms of life in, ii. 621. Erysipelas, cxxxiv. Estor, M., Bacteria in cells of ani- mals, ii. 342. Euglenae, modes of origin of, ii. 421 ; heterogenetic transformations of, ii. 434 ; into fungus-germs, ii. 436 ; into Monads, ii. 440 ; into Dia- toms, ii. 441 ; into Algoid cor- puscles, ii. 442 ; external vesicu- lation of, ii. 436, 440 ; minor mo- difications of, ii. 443 ; transforma- tion of, into Diatoms, ii. 444; into Desmids and Pediastrese, ii. 446 ; into Vaucheria filament, ii. 449 ; into Actinophrys and Amoe- bae, ii. 456; direct transformation of, into Ciliated Infusoria, ii. 459 ; into Oxytricha and Trichoda, ii. 462 ; into Vorticella, ii. 464, 504 ; into Amoebae and Actinophrys, ii. 505; into Rotifers, ii. 506, 518, 525; into Tardigrades and Nema- toids, ii. 525 ; into Nematoids, ii. 527; relations of, to Protococcus and Oscillatorise, Ixxxiii ; on trans- formations of, Ixxxv. Evolution, hypothesis of, i. 92 ; arti- ficial, i. 92; of complex chemical compounds, ii. 24 ; simple, ii. 1 21 ; compound, ii. 122. Faraday, on indestructibility of force, 1.15. Fermentation, cause of, related to origin of life, i. 400; Liebig's physical theory of, i. 403; vital theory of, held by Pasteur and others, i. 404 ; presence of oxygen not essential for initiation of, i. 416; conclusions on subject of, i. 420 ; three principal modes of, 1.423; analogy of, to vital pro- cesses, 1.425, ii. 186; occurrence of, in bent-neck flasks, ii. 12; two degrees of, ii. 14; theories of, in their bearing upon Conta- gious Diseases, cxlix. Fevers, Intermittent and Remittent, cxxxv ; Yellow, cxxxvii ; Typhoid and Relapsing, cxl; Typhus, cxl, cxlii, cliv;. Scarlet, cxliii, cliv. Flagellum of Monads, development of, ii. 212. Fluidity, state of, ii. 42. Food, relation of, to vital forces, ii. 1 83 ; putrid articles of, cxxiv. Foraminifera, ancient descent of, ii. 104; nature of, ii. 611 ; types of, explanation of apparent persistence of, ii. 613. Force, inseparability of matter and, i. 5 ; indestructibility of, i. 14 ; origin and distribution of, in living bodies, ii. 18.3. Fox, Dr. Tilbury, on Parasitic skin- diseases, ii. 347. Fox, Dr. Wilson, experiments on inoculability of Tubercle, cxiv. Frankland, Prof., on vital and phy- sical forces, i. 22, 54; mode of preparation of experimental flasks, ii. 438. Fungi, relation of, to Bacteria, ii. 1 34 ; to Amcebse and Monads, ii. 157; to Algae and Lichens, ii. 159; mode of origin of micro- scopic, ii. 338 ; presence of, in closed cavities, ii. 349 ; influence of conditions on development of, ii. in; exogenous origin of, from Euglenoe, ii. 436 ; in solutions containing silicates, xi-xiii ; rela- tions of, to Algae and Lichens, Ixxvi; to Amoebae, Ixxix; varia- bility of, Ixxvii. XXVI INDEX. Fungus-germs, mode of origin of, i. 183, ii. 203 ; development of, in Ammonic-carbonate solution, i. 288 ; vital resistance of, to heat, i. 315 ; origin of, in pellicle, from segmentation of Amoebae, ii. 226; origin of, from embryonal areas, ii. 233; in blood, ii. 331; from milk-globules, ii. 310; from em- bryonal spheres, ii. 401 ; resolu- tion of Euglenae into, ii. 436; in- dependent origin of, within closed flasks (see Arcbebiosis, experiments relating to). Gavarret, M., on source of energy in animals, i. 23, 48 ; mode of action of muscle, i. 30. Gay-Lussac, views of, concerning fermentation, i. 416. Gemmae, ii. 520. Gerhard t, on fermentation, i. 416. Germ-cells, ii. 96. Germs, existence of, in air, ii. 305, 538 ; two theories concerning, ii. 266 ; M. Pasteur on unequal dis- tribution of, ii. 272; M. Pouchet and others on atmospheric, ii. 275-288 ; distribution of those of Rotifers and Nematoids, ii. 535 ; absence of, in crystals, xv ; abun- dance of, in old crystals, xxv; presence of, in crystals of Am- monic Tartrate, xvi, xviii ; mode of origin of, xix, xxi, xxiii, xxv- xxix ; absence of, in newly-formed crystals, xxi, xxiv. Germ-theory of disease, cxx-cxxvii. Glanders, cxxxii. Gleocapsa, origin of, ii. 411. Gomphonema, origin of, ii. 442. Gonidia, variation in modes of growth of, ii. 164 ; of Algae, Lich- ens, and Mosses, indistinguishable from one another, Ixxiii. Gonidial-cell, heterogenetic changes in, ii. 378. Goodsir, Prof., on centres of nutri- tion, i. 146. Graham, Prof., on colloids, i. 88, 53- Grant, Prof., views concerning evo- lution of living things, ii. 165; cause of organization, ii. 584. Gregarinae, nature of, xcii ; rela- tions of, to Amoebae, xci ; to Pso- rosperms, xcii. Gros, Dr., transformations of chlo- rophyll corpuscles of Euglense, ii. 410; origin of Desmids and Diatoms, ii. 412 ; heterogenetic changes in Astasiae and Euglenae, ii. 434 ; transformation of Eu- glense into Diatoms, ii. 444 ; into Micrasterias and Arthrodesmus, ii. 448; into Confervae, ii. 451; origin of Mosses from Confervae, ii. 453; direct transformation of Euglenae into Ciliated Infusoria, ii. 459 ; origin of Vorticella as outgrowth from algoid filaments, ii. 470; process of Pangenesis in Rotifers, ii. 484 ; origin of Cilia- ted Infusoria from Rotifer-eggs, ii. 488 ; ascending transformations of Ciliated Infusoria, ii. 500 ; transformation of Actinophrys into Ciliated Infusoria or Rotifers, ii. 505 ; of winter-spore of Vol- vox into Rotifers, ii. 506 ; of Euglenae into Rotifers, ii. 507 ; of Euglense into Nematoids, ii. 527; origin of Entozoa, ii. 539; transformations of Euglenae and Astasiae, Ixxxv. Grove, Mr., on correlation of phy- sical forces, i. 9, 18. Gruithuisen, on fermentative changes in infusions, i. 418. Guerin-Me'neville, M., on independ- ent origin of Muscardine, ii. 326. Haeckel, Prof., on original evolution of Life, i. 92 ; Protista and di- visions of, i. 115 ; reproduction of Protomyxa, i. 193. Halford, Prof., on snake-poisoning s / N D E X. XXVll Hallier, Prof., on micrococci, i. 283. Hartig, Prof., on transformation of Phytozoa of Liverworts, Ixxiv. Harvey, William, on Heterogenesis, i- 255. Hassall, Dr. A. H., on formation of spore of Vaucheria, i. 173. Heat, as a mode of motion, i. 7 ; relation of, to mechanical energy, i. 8-12 ; influence of, on vital processes, i. 21 ; its relation to nerve functions, i. 35 ; vital re- sistance to, i. 311; resistance of spores of Fungi to, i. 316; of Bacteria and Vibriones to, i. 317, 429 ; dissociating effect of, on compounds, ii. 43. Heredity, law of, ii. 94-103. Heterogenesis, i. 245 ; distinction between Archebiosis and, i. 249 ; various modes in which it may occur, (Table) i. 252 ; ancient and modern views concerning, ii. 172181 ; classification of varie- ties of, ii. 182 ; in products of animal secretions, ii. 310; in tis- sues of plants, ii. 317; frequency of, amongst lowest organisms, ii. 561 ; varieties of, ii. 563; origin of Monads, Fungus-germs, Ciliata, and Rotifers, by synthetic, ii. 192- 263, SH-S^i; limits to., ii. 539; future researches connected with, ii. 540 ; different varieties of, (Table) ii. 545. Hicks, Dr. Braxton, production of Amoebae in moss-radicles, ii. 376 ; of Monads, ii. 410 ; Gleocapsa, ii. 41 1 ; variability of lower Algae and their relations to Lichens and Mosses, liii-lxxiii. Hildgard, Mr. T. C., mode of origin of Vorticella, ii. 470; on trans- formations of Ciliata, ii. 495. Hofmeister, on free cell-formation in Phanerogamia, i. 190. Holland, Sir Henry, on spread of Epidemic Diseases, cxix. Homogeny, meaning of term, i. 245. Hooping-cough, cxliii, cliv. Huxley, Prof., on Bathybius, i. 122 ; on cellular theory, i. 158 ; doc- trine concerning living matter, i. 310; views concerning Individu- ality, ii. 553 ; on persistent types, ii. 614. Hydatina, origin of, from Chloro- coccus corpuscles, ii. 514; from Euglenre, ii. 518. Hydrophobia, cxxx, cxxxii, cxlviii. Individual, views concerning mean- ing of term, ii. 542 ; nature of, ii. 569. Individuality, views concerning, ii- 553 5 objections to views of Dr. Carpenter and Prof. Huxley, 553-556. Influenza, cxxxix. Iron, influence of, on new-born pro- toplasm, ii. 157. Itzigsohn, on transformation of Os- cillatorise, Ixxxiii. Johnson, Mr. Metcalfe, converti- bility of Ciliated Infusoria, ii. 496 ; transformation of these into Rotifers, ii. 504. Jones, Dr. Bence, on Physical Theory of Life, i. 62. Lamarck, doctrines of, concerning Life, i. 260 ; cause of Organiza- tion, ii. 584. Laticiferous vessels, alterations in globules of, ii. 318. Lavoisier, M., on source of animal heat, i. 25. Leptothrix filaments, description of, i. 277; development of, ii. 138, xxii. Leucocytes, mode of origin of, i. 221. Lewes, Mr. G. H., on neurility, i. 36 ; life and organization, i 69 ; on multiple evolutions of living matter, ii. 75 ; on theories of de- velopment, ii. 268. Lichens, origin of spores in, i. 183 ; XXV111 INDEX. relations of, to Fungi, ii. 159; to lower Algse, liii-lviii ; to Mosses and Fungi, Ixvi; interchangeabi- lity of Algse, ii. 452. Liebig, Baron, on physical theory of fermentation, i. 403 ; analogy of fermentation to some vital pro- cesses, i. 425 ; formation of albu- minates in plants, ii. 30. Life, views of ancient philosophers concerning, i. 56 ; vitalistic theo- ries of, i. 59 ; Dr. Bence Jones on physical theory of, i. 62 ; defini- tions of, i. 70-77; dependent upon certain material collocations, i. 78 ; not abruptly limited, i. 79 ; speculations concerning original evolution of, i. 93 ; physical the- ory of, reconcilable with vital phenomena, i. 104; succession of, on the earth, i. 137-142; charac- teristics of, displayed by proto- plasm, i. 153; doctrines concern- ing, i. 308 ; destruction of, by heat, ii. 3 ; evolution of, ii. 103 ; dependence of, upon decomposi- tion, ii. 185 ; theories concerning, ii. 1 74 ; variability of primordial forms of, ii. no, 137, 143, 145. Lindley, Dr., on reproduction of Algals by zoospores, i. 171; on zoospores in Achlya, i. 180. Lindsay, Dr. Lauder, on relationship between Fungi and Lichens, ii. 1 59. Living matter, conversion of not- living into, i. 103, ii. 77; no dis- tinct line between not-living and, i. 127; influence of heat upon,.i. 429 ; origin of, from colloid mole- cules, ii. 26 ; process of produc- tion of, ii. 27; the result of mole- cular combination, ii. 27 ; pro- duction of, in saline solutions, ii. 30; influence of organic impuri- ties on evolution of, within closed flasks, ii. 33 ; influence of exter- nal conditions on development of, ii. 107; nature of, ii. 123; differ- entiation of, identical with organ- ization, ii. 127; discontinuous growth of, ii. 138; various forms assumed by new-born, ii. 155 ; influence of iron upon, ii. 158; formation of, in living organisms, ii. 185; homogeneous, tends to become heterogeneous, ii. 585 ; heterogeneity of, principally de- pendent on internal polarities, ii. 586 ; initial differences of, ii. 592 ; possibility of silicon replacing carbon in, x. Living things, definition of, i. 72 ; nature of matter of, i. 83, 96 ; origin of lowest, compared with that of crystals, i. 298 ; resistance of, to heat, i. 317, 429; occur- rence of, in vacuo, i. 347-350 ; origin of, from organic matter, ii. 308 ; persistence of forms of low- est, ii. 104-108; modes of origin of, ii. 545 ; nature of lowest, ii. 557 ; Developmental tendencies of, ii. 558. Longet, on contractility of muscle, i. 28. Lyell, Sir Chas., on geological re- cord, ii. 623. Maddox, Dr., on atmospheric germs, ii. 283. Malaria, cxxxv. Man, origin of, ii. 622, 628; his advent, ii. 628 ; development of brain of, ii. 628, 630 ; his intel- lectual and moral nature, ii. 629 ; probable date of first appearance, ii. 629 ; limits to variation of ex- ternal form of, ii. 630 ; improve- ment in race of, ii. 631 ; preju- dices concerning origin of, ii. 631 ; future of the race, ii. 633. Mantegazza, Prof., researches of, i. 263, 434. Matter, indestructibility of, i. 3 ; in- separability of force and, i. 4. Max Schultze, nature of cell, i. 1 50. Measles, cxliii, cliv. Medicine, practice of, influenced by theories, cix. / N D EX. xxix Medusae, direct development of some explained, ii. 571. Metamorphosis (see Transforma- tion). Meunier, M. Victor, experiments of, with bent-neck flasks, ii. 8. Micrococci, Prof. Hallier, i. 283. Milk-globules, conversion of, into fungus-germs, ii. 310. Milne-Edwards, M., on Pansper- mism, ii. 271. Mites, probable mode of origin of, ii. 540 ; reproduction in, ii. 551. Mivart, Mr. St. G., on cause of or- ganization, ii. 583 ; on internal tendencies to, ii. 60 1. Molecular composition, nature of bodies dependent upon, ii. 49. Monads, description of, i. 267 ; evo- lution of, ii. 196, 388 ; origin of, in pellicle, ii. 196, 212, 214; interchangeability of Amoebae and, ii. 218; origin of, from embryonal spheres of Nitella, ii. 402 ; from chlorophyll corpuscles, ii. 409 ; from outgrowths of Eu- glense, ii. 436 ; resolution of Eu- glenae into, ii. 440. Monera, growth and reproduction of, i. 153. Montgomery, on cell-forms assumed by Myeline, i. 52. Mosses, origin of, from Confervae, ii. 452 ; observations of M. de Brebisson on, ii. 454 ; relations of, to Lichens and Algae, Ixiii-lxvi. Moxon, Dr., on fission of Ciliated Infusoria, ii. 291. Mucous membranes, development of organisms on, ii. 345. Miiller, O. F., on spontaneous gen- eration, ii. 179. Mumps, cxxxix. Murchison, Dr., on origin of fevers, cxl. Murphy, Mr., on origin of species in wild state, ii. 598. Muscardine, nature of, ii. 324-330. Muscle, contractility of, i. 26 ; mode of action of, i. 30; source of power in contraction of, i. 33, 54- Mushrooms, cultivation of, ii. 433. Nai'des, a probable origin of, ii. 540. Natural Selection, ii. 107 ; Mr. Dar- win on, ii. 572 ; meaning of phrase, ii. 572-576; limitation to influence of, ii. 573; two mean- ings of, ii. 574, 600. Nectarine, convertibility of, and Peach, ii. 596, 598. Needham, on spontaneous genera- tion, i. 258; theory of life, ii. 174. Nematoidea, development of ova in, i. 200 ; origin of, from Eu- glenae, ii. 466 ; transformation of Actinophrys into, ii. 525; mode of origin of, from resting-spore of Vaucheria, ii. 529; reproduction in, ii. 532. Nerve activity, source of heat during, i. 40. Nervous system, constituents of, i. 35 ; functions of, dependent on blood-supply, i. 37; persistence of function after apparent death, i- 37- Neurility, i. 36. Newport, Mr., on vital forces, i. 1 7. Nicolet, on germ-formation in Amoe- bae, i. 197; modes of origin of Amoebae and Actinophrys, ii. 382 ; mode of origin and transforma- tions of Trichomonas, ii. 384 ; transformations in Chara fila- ments, ii. 474 ; heterogenetic ori- gin of Rotifers, ii. 509 ; on Amoe- bae, xc. Nitella, transformations in, ii. 399 ; transformations of Chlorophyll corpuscles of, into Monads and Amoebae, ii. 407 ; formation of embryonal spheres in, ii. 400 ; their transformations into Bacte- ria and Pythium corpuscles, ii. 401 ; into Monads, ii. 402; into Amoebae and Actinophrys, ii. 404 ; into Ciliated Infusoria, ii. 494; XXX INDEX. into complex egg-like bodies, ii. 405. Nordmann, M., production of Cili- ated buds from embryos of Gaste- ropods, ii. 488. CEdogonium, mode of origin of 'seed-cell' in, i. 177. Onimus, M., on mode of origin of leucocytes, i. 221. Organic compounds, mode of for- mation of, in plants, i. 23 ; in- fluence of physical forces on evo- lution of, ii. 38 ; artificial pro- duction of, i. 50, 94; views con- cerning, i. 81. Organic molecules, Buffon on, ii. 174. Organisms, desiccation of, i. 104 ; tenacity of life in lowest, i. 106 ; death of higher, i. 108 ; degree of individuation in, i. 1 1 1 ; death in lower, i. 112; classification of lowest, i. 114; vital resistance of, to heat, i. 312 ; multiplication of, truest test of life, i. 320; views concerning origin of, ii. 71 ; on independent evolutions of, ii. 75 ; reproduction amongst, ii. 87-103, 116 ; cause of reproduction of, ii. no; origin of green, ii. 157; de- velopment of corpuscular, ii. 198 ; segmentation of lower, into fun- gus-germs, ii. 226 ; mode of origin of, in pellicle, ii. 235 ; assump- tions respecting, ii. 254; origin of living units from pre-existing, ii. 308 ; presence of, in bent-neck flasks, ii. 8 ; variability of lowest, ii. 259, 557, 607 ; modes of death of, ii. 37 1 ; tendency of, to develop into higher, ii. 432; convertibility of lower, ii. 492, 558 ; influence of size of heterogenetic matrix on forms of, ii. 473 ; modes of repro- duction in, ii. 548 ; frequency of hetercgenesis amongst lowest, ii. 561 ; varieties of heterogenesis . .arnongst, ii. 563 ; limits to, ii. 609, 610; lowest, of present day, their descent, ii. 617. Organizable matter, nature and composition of, i. 83 ; molecular re-arrangement of, i. 97 ; physical explanation of process, i. 98. Organization, discussion of cellular theory of, i. 158 ; molecular theory of, harmonizes with evolution hy- pothesis, i. 162 ; differentiation identical with, ii. 127 ; causes regulating complexity of, ii. 130; existence of internal principle of, ii. 582 ; internal tendencies to, ii. 591, 603; Dr. Erasmus Darwin's views on, ii. 583 ; Prof. Owen and Mr. St. George Mivart on cause of, ii. 583; Lamarck and Prof. Grant on cause of, ii. 584; nature of internal principle of, ii. 585 ; this not believed in by Mr. Spencer and Mr. Dai-win, ii. 585-594 ; strength of internal principle shown by similarity of lowest organisms in different regions, ii. 593. Origin of living things, experiments relating to, with calcined air, i. 337-343; different results obtained by other experimenters, i. 344 ; experiments relating to, with or- ganic solutions, i. 355-360; re- marks on, i. 360 ; experiments relating to, with saline solutions, i. 363-372; remarks on, i. 372; M. Pasteur's experiments and views concerning, i. 374-384 ; comparative experiments connect- ed with, i. 385-391, ii. 18; dele- terious effects of acidity of solu- tion increased by heat, i. 392-396 ; experiments concerning, in super- heated flasks, i. 441-470 ; remarks on, i. 471-475 ; facilitated by diminution of pressure, ii. 20 ; oc- curring in organic solutions, ii. 22, 71 ; theoretical views respect- ing, ii. 254. Otostoma, origin and development, ii. 479; origin of, from Nitella filament, ii. 482. I N D E X. XXXI Ova, in lower animals, i. 199-202 ; in higher animals, i. 203-211. Owen, Prof., on cause of organiza- tion, ii. 583 ; internal organizing tendencies, ii. 591. Oxytricha, origin of, from Euglense, ii. 462 ; from Chlorococcus vesi- cles, ii. 467 ; metamorphosis of Vorticella into, ii. 493 ; transform- ation of, into Trichoda, ii. 496. Palseontological Record, interpreta- tion of, ii, 620; imperfection of, ii. 622. Pangenesis, Mr. Darwin's hypothesis of, ii. 98, 603 ; previous use of term by Dr. Gros, ii. 484; in Tardigrades, ii. 549 ; peculiarities of, in Tardigrades and Rotifers, . 55i. Panspermism, views of Spallanzani and Bonnet on, i. 259 ; nature of theories, ii. 267 ; untenability of hypothesis of, ii. 305, 359, 367, 53. Paramecium, evolution of, from pellicle, ii. 240-250; its conver- sion into Nassula, ii. 251 ; trans- formations of, ii. 496. Parasites, higher, ii. 309, 539 ; lower, in blood of animals, ii. 324-337; in tissues of plants, ii. 317, 338-342; in tissues of ani- mals, ii. 342-358; within eggs of, ii. 366. Pasteur, M., on resistance to heat of spores of fungi, i. 316; double nature of results in experiments by, i- 34. 345 374. 3 8 45 vital theory of fermentation, i. 404 ; his explanation of experiments with bent-neck flasks, ii. ii ; on atmospheric germs, ii. 271-275, 286. Peach, converted into Nectarine, ii. 59 6 > 59 8 - Peacock, black-shouldered, origin of, ii. 598. Pbrine, nature of, ii. 352, cxxii. Pellicle, formation of, on organic infusion, i. 266; composition of, i. 277, ii. 193; formation of em- bryonal areas in, ii. 198; remarks concerning changes in, ii. 205 ; series of changes in, leading to evolution of Monads, ii. 215; other changes in, leading to evo- lution of Fungus-germs, ii. 231- 235 ; evolution of Ciliated Infu- soria from, ii. 237-254; changes in, throw light upon mode of ori- gin of living matter, ii. 262 ; con- ditions favourable to production of Ciliated Infusoria, ii. 244, 299. Penicillium, evolution of, ii. 195 ; conversion of milk-globules into, ii. 310. Peranemata, origin of, from Euglenae, ii. 459 ; from Rotifers, ii. 484 ; conversion of, into Ciliated Infu- soria, ii. 485. Peziza, Corda on formation of spores in, i. 184. Philodinioe, mode of origin of, ii. 54- Physcia, formation of spore in, i. 186. Physical Forces, convertibility of, i. 1 3 ; correlation of vital and, i. 16-49, 6>' action of, upon living tissues, i. 98 ; influence of, on evo- lution of organic compounds, ii. 38. Physiological units, ii. 23, 90, 98, 603, Phytoids, ii. 542, 553. Pineau, M., on formation of spore in Physcia, i. 186; observations of heterogenetic changes, i. 261 ; on origin of Penicillium, ii. 195 ; of Monads, ii. 196 ; of Vorticellse, ii. 252, 471 ; of Enchelys, ii. 238 ; metamorphoses of Vorticellce into Oxytrichse, ii. 493. Plaesconia, origin of, from Chloro- coccus vesicles, ii. 467. Plague, cxliii. Plants, functions of, related to those of Animals, i. 129; M. Brong- niart on development of, in past XXX11 I N D EX. ages, i. 137; M. Saussure on, i. 139; growth of, ii. 27; occurrence of heterogenesis in, ii. 317- Plastide-particles, i. 267, 270. Plastides, i. 152, 267. Polarity, Herbert Spencer on or- ganic, ii. 23, 94 ; its operation in higher organisms, ii. 595 ; an ever- potent cause of form and struc- ture, ii. 60 1. Pouchet, M., on vital force, i. 248 ; on spontaneous generation, i. 263; interchangeability of forms of Fungi, ii. 151 ; heterogenesis and vitalism, ii. 180; origin of Monads, ii. 196 ; of Paramecia, ii. 240; of Vorticellae, ii. 471 ; atmospheric germs, ii. 275 ; apparatus for showing connection of Ciliata with Pellicle, ii. 300. Pringsheim, Prof., on transformations in Algse, ii. 374. Pritchard, on Algse and their allies, ii. 1 60; modes of succession of organisms in infusions, ii. 502 ; variations in habitat of Infusoria, 535- Progressive development, ii. 583, 588, 590, 602. Protamcebae, i. 117, 121, 125. Protista, i. 115-126 ; divisions of, i. 117; modes of reproduction amongst, i. 116, 192, ii. 548. Protococcus, relation of, to Algse, Lichens, and Mosses, ii. 163 ; pro- ducts of transformations of, Ixxxii. Protomyxa, process of reproduction in, i. 193. Protonema, changes of, Ixvi-lxxii, Protoplasm, properties of, i. 127; independent origin of, ii. 31, 77. Protoplasta, i. 153; development of germs in, i. 197. Psorosperms, ii. 352,cxxii. Puerperal Fever, cxxxiv. Pyaemia, cxxxiv. Rainey, Mr., on 'molecular coal- escence,' i. 51 ; on formation of Calculi, ii. 60 ; nature of starch- grains, ii. 66. Redi, on spontaneous generation, i. 257- Reissek, Prof., on metamorphoses of Chlorophyll corpuscles and pollen -grains, ii. 432. Reproduction, act of, best sign of life of Bacteria, i. 320; funda- mental nature, ii. 91 ; limitations of process in complex organisms, ii. 95 ; in Rotifers, ii. 522 ; sexual mode of evolution of, ii. 548, 552; ultimate nature of, ii. 561 ; sexual modes, commencement of, ii. 564 ; nature of ' alternate ' pro- cesses of, ii. 565. Reproduction, different modes of, 'fable facing ii. 552. Reproductive units, mode of origin of, i. 169-214, 232. Robin, Charles, on independent origin of Leucocytes, i. 220 ; blood-change in parasitic dis- eases, ii. 361. Rotifers, resolution of, into Actino- phrys and Peranema, ii. 484 ; into Arcellinse, ii. 486 ; origin of Ciliated Infusoria from eggs of, ii. 488 ; modes of analytic hetero- genesis in, ii. 489 ; heterogenetic modes of origin of, ii. 501-523; reproduction in, ii. 522, 549. Rumford, Count, heat as a mode of motion, i. 7. Samuelson, Mr. James, on atmo- spheric germs, ii. 280. Sanderson, Dr. Burdon, effect of desiccation on Bacteria, ii. 5 ; Microzymes in air, ii. 7 ; experi- ments on inoculability of Tuber- cle, cxiv. Sang de rate, M. Davaine on, ii. 362. Sarcina, i. 286 ; nature of, iii ; pro- ducts allied to, v ; bodies resem- bling, in silicated solution, xiv. Schaaffhausen, Prof., on heterogene- tic transformations, ii. 453, 499. / N D EX. XXXlll Schelling, theory of life, i. 77. Schleiden, sources of nutriment of plants, i. 136. Schultze, on Panspermism, i. 262. Schwann, on origin of cells, i. 144 ; on Panspermism, i. 262 ; method of experimentation with calcined air, i. 337. Scolecida, modes of origin of repre- sentatives of, ii. 539. Seguin, M., on convertibility of forces, i. 9. Silicates, solutions of, containing Fungi, xi-xiii ; spiral fibres, xiv ; bodies resembling Sarcina, xiv. Silicon, as a possible substitute for carbon in living matter, x. Small-pox, views on, cxxvii ; origin of, cxliv ; contagiousness of, cxlix. Snake-poisoning, cxxviii, cxxx. Snow-flakes, ii. 280. Solution, nature of process, ii. 44. Spallanzani, l'Abb6, on Pansperm- ism, i. 259. Species, meaning of term, ii. 547 ; mutability of, ii. 548 ; nothing corresponding to, amongst lower forms, ii. 568 ; nature of, ii. 569 ; influenced by change in external conditions, ii. 577-582 ; by use and disuse, ii. 577; to what ex- tent influenced by natural selec- tion, ii. 578 ; Darwin on influence of new external conditions upon, ii. 591 ; variation of, ii. 598 ; fre- quency of spontaneous variation in unknown, ii. 599 ; modes in which transmutations are brought about, ii. 600 ; Mr. Darwin's views con- cerning, ii. 601-603. Spencer, Mr. Herbert, on converti- bility of forces, i. 13 ; on meaning of persistence force, i. 14 ; corre- lation of vital and physical forces, i. 22 ; consciousness, i. 45 ; mor- phological development, i. 52 ; characteristics of living things, i. 74 ; elements of organizable mat- ter, i. 84; instability of protein compounds, i. 86 ; original evolu- tion of life, i. 92 ; artificial evolu- tion of organic matter, i. 94; oper- ation of physical forces upon living tissues, i. 98 ; evolution of living matter, i. 163 ; organic polarity, ii. 23 ; physiological units, ii. 23, 90, 98 ; law of heredity, ii. 94, 97; nature of evolution, ii. 120; two meanings of natural selection, ii- 573 ; denies existence of internal organizing tendencies, ii. 585 ; cause of organization, ii. 587 ; his explanation of existence of undif- ferentiated organisms in present day, ii. 587-589; physiological units, ii. 603 ; limits to variability of species, ii. 610. Spermatozoa, development of, i. 213. Sperm-cells, ii. 96. Spiral fibres, v ; where found, viii ; in association with mycelium, viii ; in silicated solution, xiv. Spirillum, i. 277, ii. 139. Spirogyra, transformations in, ii. 3 8 7-393. Spontaneous Generation, reason for rejecting term, i. 244 ; views of ancient writers concerning, i. 253; other views concerning, i. 255- 263 ; two processes included under term, ii. 172. Spores, mode of formation of, in CEdogonium, i. I77 i n Zygne- meacese, i. 1 79 ; in Fungi and Lichens, i. 183 ; in Peziza, i. 184; in Hydrodictyon, i. 186 ; Physcia, i. 186. Starch-grains, production of, ii. 65. Steenstrup, on alternate generation, ii. 565. Stein, views concerning Acinetre and Vorticellse, xciv-xcvii. Survival of the fittest, ii. 575. Syphilis, cxxxii. Tables relating to : (i) origin of living things, i. 252 ; (2) modes of origin of independent living units, ii. 545 ; (3) modes of reproduction XXXIV INDEX. with reference to the origin and gradual appearance of sexual dif- ferentiation, Table facing ii. 552 ; (4) modes of development in relation to sexual multiplication occurring during its progress, ii. 567 ; (5) causes which determine forms of organisms, ii. 600; (6) communi- cable diseases, cxlvi. Tardigrades, origin of, from Eugle- nse, ii. 466 ; transformation of Actinophrys into, ii. 524; repro- duction in, ii. 532 ; Pangenesis in, ii. 549 ; peculiarities of Pangenesis in, ii. 551. Theory, test of true, ii. 605. Thomson, Prof. Allen, on develop- ment of ova in Ascarides, i. 200 ; on individuality, ii. 556. Thomson, Sir William, on geological time, ii. 619. Toruloe, i. 273 ; mode of origin of, in solutions, i. 281 ; nature of, ii. 141 ; development of, into Fungi, ii. 145-154; interchangeability of Bacteria and, ii. 143 ; origin of, within closed flasks (see Arcbebio- sis, experiments relating to). Transformations, in Spirogyra, ii. 374> 387 ; in Moss-radicles, ii. 376 ; in Gonidial-cell, ii. 378; of Trichomonas, ii. 384 ; in Vauche- ria, ii. 394 ; in Nitella, ii. 399 ; of Chlorophyll vesicles, ii. 415; of Chlorophyll vesicles of Vaucheria, Nitella, etc. into Desmids, ii. 418; of cell-contents of Conferva into Euglense, ii. 421 ; of Spirogyra into Astasiae, ii. 421 ; of Potamo- geton into Euglense, ii. 422; M. Kiitzing on, of vegetable organ- isms, ii. 432; Reissek on, of Chlo- rophyll vesicles and pollen-grains, ii. 432 ; of Euglense, ii. 436-466; of Ciliated Infusoria, ii. 492-504; of Actinophrys into Rotifers, ii. 504 ; of Vegetal vesicles into Ro- tifers, ii. 506-521 ; of Rotifers into Nematoids, ii. 522 ; of Acti- nophrys into Nematoids and Tar- digrades, ii. 524; of Euglense into Rotifers, Tardigrades, and Nema- toids, ii. 525 ; of resting-spore of Vaucheria into Nematoids, ii. 528. Trecul, M., on development of Toru- Ise, ii. 147 ; origin of Amylobacter, ii. 318. Treviranus, experiments in reference to heterogeny, i. 259. Trichoda, origin of, from Euglenae, ii. 462; metamorphosis of Oxy- trica into, ii. 496. Trichomonas, origin and transform- ations of, ii. 384. Tubercle, non-specific nature of, cxiii, cxvii ; generalization of, cxvi. Turpin, M., heterogenetic changes in milk-globules, ii. 311 ; mode of origin of Uredo, ii. 339. Types, persistence of, ii. 606; per- sistent, Prof. Huxley on, ii. 615; explanation of persistent, ii. 616- 619; dominant, ii. 621. 623; of fish and insect, ii. 624 ; estimation of worth of, ii. 625 ; vertebrate, ii. 626 ; elaboration of, ii. 627. Units, physiological, ii. 23, 90, 98. ii. 603. Variation, 'spontaneous,' meaning of, ii. 595 ; instances of, ii. 596- 599- Varicella, cxliii. Vaucheria, formation of spore of, i. 173; transformations in, ii. 394.; of spore of, into Nematoids, ii. 528. Vegetable forms; interchangeability of animal and, ii. 431, 434. Vibriones, nature of, i. 274; vital resistance of, to heat, i. 317. Virchow, Prof., doctrines concern- ing, i. 148 : cellular pathology, i. 158 ; activities of tissue-elements, i. 167. Vital forces, correlation of physical and, i. 16-49, 6 ; dependent on INDEX, XXXV oxidation of blood, i. 48 ; trans- mutation of physical force into, i. 67 ; no evidence for existence of a special, i. 83 ; relation of food to, ii. 183. Vital processes, effect of light and heat upon, i. 16 ; amenable to physico-chemical laws, i. 54 ; in- explicable nature of most inti- mate, i. 55, ii. 256, 534 ; analogy of fermentation to, i. 425, ii. 186. Vorticellse, mode of origin of, ii. 252 ; from Euglense, ii. 464; from Algoid-vesicles and Moss-sporan- gia, ii. 469 ; other modes of ori- gin of, ii. 469 ; from filaments of Nitella and hlamydococcus cor- puscles, ii. 470 ; by synthetic Heterogenesis, ii. 471 ; metamor- phosis of, into Oxytricha, ii. 493 ; into Rotifers, ii. 502, 511 ; origin of, from Actinophrys, xcv ; rela- tions of, to Acinetse, xcv ; conver- sion of, into Actinophrys, xcv. Wallace, Mr., on natural selection, ii. 574; on means of changing colour in feathers, ii. 597 ; test of true theory, ii. 604; age of human race, ii. 629 ; development of brain in man, ii. 630 ; future of human race, ii. 633. Watson, Sir Thomas, on non-suscep- tibility to contagion of small-pox and measles, cxlix. Winter-eggs, of Hydatina senta, ii. 514. W T yman, Prof. Jeffries, experiments relating to origin of living matter, i. 435 ; on analogical evidence concerning origin of living matter, i. 471 ; on atmospheric germs, ii. 282. Zooids, ii. 542, 553. Zoospores, mode of origin of, in Al- gse, i. 171 ; formation of, in Vau- cheria, i. 173; in Achlya, i. 180. PART I. THE NATURE AND SOURCE OF THE VITAL FORCES, AND OF ORGANIZABLE MATTER. THE BEGINNINGS OF LIFE. CHAPTER I. THE PERSISTENCE OF FORCE CORRELATION OF THE VITAL AND PHYSICAL FORCES. Indestructibility of Matter. Forces modes of motion. The doctrine of Conservation of Energy. History of. The unit of Heat. Con- vertibility of Physical Forces. Indestructibility of Force. Gradual growth of doctrine of Correlation of Physical and Vital Forces. Source of Energy manifested in Plants and Animals. Doctrines concerning Animal Heat. Its real mode of Origin. Power of movement in Animals. Laws regulating muscular Contractility. The Muscle a machine in which heat transforms itself into Me- chanical Energy. Comparison between Muscle and Steam- Engine. Nervous phenomena. Neurility. Sensory and motor nerves have similar functions. Dependence of Nerve action upon due supply of blood. Remarkable experiments illustrating this. Evolution of heat and increased chemical change accompaniments of Nerve action. Different functions of Nervous System. Relations of Con- sciousness and Mind. Correlations of Consciousness not ascertain- able. Conclusions. doctrine that Matter is indestructible may JL now be regarded as one of the most universally accepted utterances of science. It is already firmly rooted, and the belief in its truth is gradually spreading deeper and wider as education advances. All must admit that there is an immeasurable difference between B 2 THE BEGINNINGS OF LIFE. mere change of form and destruction, though in past times and even at present amongst the uneducated the former has been often mistaken for the latter. Such misconceptions, however, were natural enough in the past, and even now they are quite in harmony with the defective general knowledge of those who still entertain them: their occurrence does not in the least tend to diminish our well-grounded belief in the indestructibility of matter. Of late years, too, experimental investigators as well as purely speculative enquirers have alike been gradually tending towards the recognition of the com- plemental doctrine of the essential oneness and inde- structibility of Force. Matter, they say, is indestructible, and so also is force. Forces are c modes of motion,' and motion is continuous. The very idea of motion, however, cannot be realized in thought except it be in connection with a something which moves though the moving body may be infinitely great or infinitely small. We may imagine molar motion, or motion of a mass, as exhibited by the revolution of a planet or of a sun in its orbit ; and we may imagine molecular motion amongst the particles of a cosmical sether, even though this aether itself may be so subtle as to elude all present means of recognition. But, though motion is inseparable from matter, it is, as we have intimated, continuous or persistent, and, therefore, communicable from particle to particle. Ethereal pulses of solar derivation impinging upon the surface of our earth THE BEGINNINGS OF LIFE. may produce effects which, in part, manifest them- selves in our consciousness as sensations of heat ; or, acting upon other bodies, organic and inorganic, may in them produce such molecular re-arrangements such modifications of form and nature as will suffice to alter their qualities or attributes. Matter, then, may undergo changes of form it may be now solid, now liquid, and now an invisible gas ; whilst the disguised Force or Motion, owing to such different modes of collocation of the atoms of matter, may manifest itself to us in different ways, but in its essence it remains as the underlying and indestruct- ible cause of the attributes of matter. So that at the same time that force is indestructible, it is moreover incapable of existing alone and independently of matter. We cannot conceive force save as inhering in, and appertaining to some body; we cannot con- ceive a body, or matter, existing, devoid of all at- tributes or force manifestations. Both are mutable, both indestructible, and both, so far as we know, quite incapable of existing alone. The growth of modern scientific opinion concerning force has necessarily had much influence in modifying the doctrines concerning Life which were formerly in vogue. During the present century the labours of earnest workers of all kinds have done much towards the over- throw of the ancient and long-predominating meta- physical conceptions of Life. Chemists, physiologists, and others have striven manfully to dispel the mists THE BEGINNINGS OF LIFE. and darkness which previously enshrouded all vital phenomena, and few, we suppose, would deny that the results of their labours had sent gleams of light into corners previously unillumined. However much there may be of the mysterious and occult still remaining, some of the phenomena, at least, formerly looked upon as essentially c vital' and, therefore, well-nigh in- explicable are now recognized as depending in great part upon purely physical processes. But before stating what are the modern conceptions of Life what views are now possible it will be well to glance briefly at the labours of those who have helped to build up that doctrine of the Correlation of Forces, or Con- servation of Energy, whose influence has been so great in upsetting the old metaphysical conceptions to which we have referred. It is not to be expected that the doctrine of the Conservation of Energy should have sprung fully formed from the brain of any single man. The progress of scientific thought and experiment had been gradually tending in this direction during the closing years of the last century, and the doctrine has since been built up and perfected by the labours of many workers and thinkers. The germs of it are, however, to be found, stated with remarkable clearness, even more than two centuries ago, in the writings of Lord Bacon, who says in the twentieth Aphorism of his c Novum Organum:' c When I say of motion that it is the genus of which heat is a species, I would be understood to mean, not THE BEGINNINGS OF LIFE. that heat generates motion (though both are true in certain cases), but that heat itself, its essence and quiddity, is motion and nothing else Heat is a motion, expansive, restrained, and acting in its strife upon the smaller particles of bodies V Locke, also, shortly afterwards, expressed himself in much the same terms. He said: c Heat is a very brisk agitation of the insensible parts of the object, which produces in us that sensation from whence we denominate the subject hot- so that what in our sensation is heat^ in the object is nothing but motion? But it was not till quite the close of the last century, in 1798, that Benjamin Thompson, afterwards Count Rumford, announced to the Royal Society his conviction, based upon real experimental evidence, that heat was a mode of motion. Whilst superintending the boring of cannon in the military arsenal at Munich, Count Rumford was much struck with the heat acquired by the brass after it had been bored for a time, and also with the intense heat of the metallic chips which were separated by the borer 2 . He then instituted the most careful experiments to ascertain the source of this heat, and in his memoir, after having de- tailed the nature and results of these experiments, he made the following remarks in opposition to the then prevalent notion that heat was a material substance, a kind of igneous fluid named c caloric:' c We have 1 Bacon's Works, vol. iv. Spedding's Translation. 2 See Tyndall's ' Heat Considered as a Mode of Motion,' 1863, p. 53. THE BEGINNINGS OF LIFE. seen that a very considerable quantity of heat may be excited by the friction of two metallic surfaces, and given off in a constant stream or flux in all directions y without interruption or intermission, and without any signs of diminution or exhaustion. In reasoning on this subject we must not forget that most remarkable circum- stance^ that the source of the heat generated by friction in these experiments appeared evidently to be in- exhaustible. It is hardly necessary to add, that any- thing which any insulated body or system of bodies can continue to furnish without limitation cannot possibly be a material substance-, and it appears to me to be extremely difficult, if not quite impossible, to form any distinct idea of anything capable of being excited and communicated in those experiments, except it be MOTION.' In 1812 also, Sir Humphrey Davy in his first Memoir 1 brought forward most valuable scientific evi- dence to show that no such thing as c caloric ' existed, that heat was not an elastic fluid, and that the c laws of the communication of heat are precisely the same as those of the communication of motion.' One of his experiments was of the most conclusive nature. c He succeeded in melting two pieces of ice by rubbing them together in vacuo, at the same time preventing the access of external heat. The water produced in this experiment has a much higher relative heat than the ice; hence the potential heat which caused the ice to melt must have been obtained by the conversion of 1 Sir Humphrey Davy's Works, vol. ii. THE BEGINNINGS OF LIFE. the mechanical force employed for the friction V For, as Sir Humphrey Davy reasoned, a motion or vibration of the corpuscles of bodies must be necessarily gener- ated by friction and percussion, and so, he adds, c we may reasonably conclude that this motion or vibra- tion is heat, or the repulsive power.' Then, in 1827, Lardner Vanuxem published in Philadelphia an essay 2 in which he speaks of caloric, light, electricity, and magnetism as being mutually convertible. His utter- ances are, however, somewhat dubious, since he at first treats of them as c four different states' of c one kind of repulsive matter', though, further on, he ac- knowledges that the existence of these as c four dis- tinct fluids, or kinds of aethereal matter, is inadmis- sible; for this conversion or change of characters is analogous to what are called the properties of bodies and not to the bodies themselves.' Again, in 1839, Seguin, in a work entitled ' De {'Influence des Chemins de Fer,' called attention to the mutual convertibility of heat and mechanical force, and he gave a calculation of their equivalent relation not differing materially from that afterwards published by Mayer and Joule. In January, 1842, in a lecture delivered before the Royal Institution, Professor Grove declared that c light, heat, electricity, magnetism, motion, and chemical affinity are all convertible material affections;' and in 1 Orme's ' Science of Heat,' 1869, p. 163. 2 'On the Ultimate Principles of Chemistry, Natural Philosophy , and Physiology.' 10 THE BEGINNINGS OF LIFE. the recently published third edition of his c Correlation of the Physical Forces,' he says, c As far as I am now aware, the theory that the so-called imponderables are affections of ordinary matter, that they are resolvable into motion, that they are to be regarded in their action on matter as forces, and not as specific entities, and that they are capable of mutual reaction, thence alternately acting as cause and effect, had not at that time been publicly advanced/ But it was also in the year 1842, though in its latter part, that Dr. Mayer 1 , a physician of Heilbronn, announced independently a doctrine substantially similar, to the effect that the imponderables were forces at once indestructible and convertible. He actually calculated the mechanical equivalent of heat out of data derived from the velocity of sound in air an intellectual feat only possible to a man of rare originality. Professor Tyndall says 2 of him, c When we consider the circumstances of Mayer's life, and the period at which he wrote, we cannot fail to be struck with astonishment at what he has ac- complished. Here was a man of genius working in silence, animated solely by a love of his subject, and arriving at the most important results some time in advance of those whose lives were entirely devoted to Natural Philosophy. It was the accident of bleeding a feverish patient at Java, in 1 840, that led Mayer to 1 ' Bemerkungen iiber die Krafte der umbeleten Natur,' Liebig's Annalen, 1842, vol. xlii. 2 Loc. cit. p. 445. THE BEGINNINGS OF LIFE. 1 1 speculate on these subjects. He noticed that the venous blood of the tropics was of a much brighter red than in colder latitudes, and his reasoning on this fact led him into the laboratory of natural forces, where he has worked with such signal ability and success/ But in the following year, 1843, Mr. Joule of Manchester published his first paper on the c Mechanical Value of Heat,' in which he detailed the most valuable results of a series of experiments, conducted whilst he was in ignorance of the labours of Seguin and of the reason- ings of Mayer. It is to him that we are principally indebted for the actual experimental determination of the mechanical equivalent of heat. A paddle-wheel was made to revolve in a copper vessel containing a weighed quantity pf water at a known temperature, The mechanical force, derived from falling weights, which was employed in turning the wheel was known ; so that when, after the wheel had revolved for a cer- tain time, the temperature of the water was estimated, and the distance through which the weights had fallen in the same time was computed, it became easy to estimate the quantity of heat which corresponded to the fall of a known weight through a given distance. Of course, corrections had to be made, allowing for the heating of the copper vessel, and of the wheel itself, as well as for the loss of heat by radiation. Similar experiments were conducted with oil and with mer- cury, though under somewhat different conditions - y and in all cases the amount of heat evolved by the friction 1 2 THE BEGINNINGS OF LIFE. of the vanes of the wheel against the various fluids was ascertained with the greatest care. The uniform results obtained in these experiments enabled Mr. Joule most satisfactorily to establish the mechanical equiva- lent of what has been termed the unit of heat. He found that the energy of a body weighing one pound which had fallen from a height of 772 feet was exactly equal to the quantity of molecular motion or heat which suffices to raise the temperature of one pound of water by one degree of the Fahrenheit scale 1 . It is needless for us to follow further the ultimate developments of this doctrine with which the names of Clausius, Rankine, Thomson, and Helmholtz are associated. We have called attention to the experi- ments and reasonings by which it has been shown that an exact relation of equivalence exists between the motion of masses produced by mechanical force, and the motion of the particles of bodies manifesting itself as heat produced by friction. Heat, therefore, has been indubitably established to be a c mode of motion;' and there is the very best reason for believing that all the other forces or affections of matter are similarly re- lated to motion, whilst they are also mutually con- vertible. Each alike may arise from, or may give origin to motion either directly or indirectly. 1 The ' unit of heat ' therefore, or that amount of heat which will raise a pound of water i Fahr, is equal to 772 'foot-pounds,' if we call the actual energy of a body weighing one pound which has fallen one foot, a foot-pound. THE BEGINNINGS OF LIFE. 13 By the rubbing of substances of a different nature together electricity is produced, as in the ordinary electrical machine. Magnetism, again, may result from motion; either immediately, in a bar of soft iron, through a repetition of percussions, which, producing motion amongst the particles of the bar, facilitate their assumption of the magnetic mode of collocation; or mediately through the intervention of electricity which lias itself been generated by motion. And, as Mr. Her- bert Spencer says 1 , c The transformations of electricity into other modes of force are still more clearly demon- strable. Produced by the motions of heterogeneous bodies in contact, electricity, through attractions and repulsions, will immediately reproduce motion in neigh- bouring bodies. Now a current of electricity generates magnetism in a bar of soft iron ; and now the rotation of a permanent magnet generates currents of elec- tricity. Here we have a battery in which, from the play of chemical affinities, an electric current results; and there, in the adjacent cell, we have an electric current effecting chemical decomposition. In the con- ducting wire we witness the transformation of elec- tricity into heat ; while in the electric sparks and in the voltaic arc we see light produced That mag- netism produces motion is the ordinary evidence we have of its existence. In the magneto-electric machine we see a rotating magnet evolving electricity. And 1 ' First Principles,' p. 254. 14 THE BEGINNINGS OF LIFE. the electricity so evolved may immediately after ex- hibit itself as heat, light, or chemical affinity. Faraday's discovery of the effect of magnetism on polarized light, as well as the discovery that change of magnetic state is accompanied by heat, point to further like con- nections. Lastly, various experiments show that the magnetization of a body alters its internal structure ; and that, conversely, the alteration of its internal struc- ture, as by mechanical strain, alters its magnetic con- dition/ We need allude to all these possibilities of change no further ; those who wish for additional in- formation may find it in Mr. Grove's work. The most attentive consideration of the facts forces us to the conclusion even to an irresistible belief that though continually varying in its modes, Force itself is indestructible or persistent. As Mr. Herbert Spencer says, such an allegation really amounts to this, that a priori possibilities and experimental evidence alike warrant us in the belief c that there cannot be an isolated force beginning and ending in no- thing ; but that any force manifested implies an equal antecedent force from which it is derived, and against which it is a reaction. Further, that the force so originating cannot disappear without result- but must expend itself in some other manifestation of force, which, in being produced, becomes its reaction ; and so on continually.' If forces are nothing but the inseparable qualities, attributes, or affections of matter, and if matter is THE BEGINNINGS OF LIFE. 15 itself indestructible, then, of course, it must follow as an a priori necessity that forces, or the attributes of matter, are also indestructible \ As Professor Faraday expresses it 2 , c a particle of oxygen is ever a particle of oxygen nothing can in the least wear it. If it enter into combination and disappear as oxygen if it pass through a thousand combinations, animal, vegetable, and mineral if it lie hid for a thousand years, and then be evolved, it is oxygen with its first qualities. Neither more nor less. It has all its original force, and only that ; the amount of force which it dis- engaged when hiding itself has again to be employed in a reverse direction when it is set at liberty Just as the chemist owes all the perfection of his ex- periments to his dependence on the certainty of gravita- tion applied by the balance, so may the physical philo- sopher expect to find the greatest security and the utmost aid in the principle of the conservation of force. 1 Those who wish to follow this subject further, and to understand what are its ultimate implications, cannot do better than read chapters vi.-ix. of Mr. Herbert Spencer's ' First Principles.' They will then see that 'persistence of force ' is really the most ultimate notion, on which the doctrine of the ' indestructibility of matter ' as well as that of the ' continuity of motion ' are alike dependent. He says : ' By the Per- sistence of Force, we really mean the persistence of some power which transcends our knowledge and conception. The manifestations either as occurring in ourselves or outside of us do not persist ; but that which persists is the Unknown Cause of these manifestations. In other words, asserting the persistence of force is but another mode of asserting an Unconditional Reality, without beginning or end.' p. 255, ist edit. 2 ' Researches in Chemistry,' pp. 454, 459. 1 6 THE BEGINNINGS OF LIFE. All that we have that is good and safe, as the steam- engine, the electric telegraph, &c., witness to that principle. It would require a perpetual motion, a fire without heat, heat without a source, action without reaction, cause without effect, or effect without a cause, to displace it from its rank as a law of nature.' The time, therefore, must come when the really funda- mental doctrine of the persistence or indestructibility of Force will be recognized by all educated persons to have an equal validity with the secondary, though more familiar, doctrine of the indestructibility of Matter. The two doctrines are correlatives, and the admission of one implies the truth of the other as a necessary consequence. Having come to an understanding as to what views we are to take of Force and of the mutual relations of the several physical forces, we now have to enquire as to the relation in which these stand to the so-called c vital forces ' manifested by Living Organisms. The first real 1 step in explanation was taken in 1 In an 'Inaugural Address,' delivered in 1868 at the Jeafferson Medical College, U.S., by Dr. J. Aitken Meigs, he claims the credit for Dr. Metcalfe of having initiated this part of the doctrine. These claims, and also others concerning Lardner Vanuxem, have been con- sidered in the 'British Medical Journal/ January 16, 1869, p. 50. Dr. Metcalfe's work, published two years earlier, in 1843, was entitled, 'On Caloric ; its Mechanical, Chemical, and Vital Agencies in the Pheno- mena of Nature.' Dr. Metcalfe seems to have been a man of much power and originality, though he still looked upon heat as a material substance, an elastic fluid named caloric. This view, of course, vitiates his treatment of the subject, though it seems clear, from the passage THE BEGINNINGS OF LIFE. 17 1845 ty Mayer of Heilbronn, in a memoir on c Organic Movement in its Relation to Material Changes/ in which he showed that the processes taking place in living organisms, animal or vegetable, were produced by forces acting upon them from without, and that the changes in their composition brought about by these external agencies were the immediate sources of those modes of force apparently generated in the organisms themselves. In the same year also Mr. Newport was led by a consideration of the relations which had been shown to exist between light and electricity by Faraday, and between electricity and nervous power by Matte ucci *, as well as ' by the known dependence of most of the functions of the body on the latter, to consider light as the primary source of all vital and constructive power, the de- grees and variations of which may, perhaps, be re- ferred to modifications of this influence on the special organization of each animal body 2 .' In the following which we subjoin, that his notions otherwise were verging in the right direction. ' All the chemical changes,' he says, ' that mark the course of nature, are attended with changes of temperature, from the slowest process of fermentation to the most rapid combustion ; that is, all the decompositions and recombinations of matter are attended with the addition or subtraction of caloric. Without the continual agency of the solar beams, the vital air, the ocean, and the solid ground would become a motionless mass of inert and chaotic matter. Without the reception of caloric from the atmosphere by respiration, the wonderful mechanism of animal motion, sensation, and life, could not go on.' 1 Physical Phenomena of living beings. 2 This passage is to be found only in the ' Athenaeum ' for Dec. 6, C 1 8 THE BEGINNINGS OF LIFE. year Mr. Grove published his now well-known work on the c Correlation of the Physical Forces/ and in this, after having spoken of the relations existing between the several physical forces, he said, C I be- lieve that the same principles and mode of reasoning might be applied to the organic, as well as to the inorganic world; and that muscular force, animal and vegetable heat, &c., might, and at some time will, be shown to have similar definite correlations/ This view was taken up by Dr. Carpenter, and was much more fully elaborated by him. In an article contributed to the c British and Foreign Medico- Chirurgical Review' for January, 1848, Dr. Carpenter maintained c that the vita/ forces, of various kinds, bear the same relation to the several physical forces of the inorganic world that they bear to each other; the great essential modification or transformation being effected by their passage, so to speak, through the germ of the organic structure, somewhat after the same fashion that heat becomes electricity when passed through certain mixtures of metals/ Then, in 1850, a memoir was read before the Royal Society, and after- wards published in the c Philosophical Transactions/ entitled, c On the Mutual Relations of the Vital and Physical Forces,' in which the whole doctrine was much 1845. Though it originally formed part of a paper which afterwards appeared in the 2Oth vol. of the ' Transactions of the Linnaean Society, but from which this particular passage was omitted by desire of the officers of the Society. THE BEGINNINGS OF LIFE. 19 more fully discussed, and Dr. Carpenter laboured most successfully to show c that so close a mutual relation- ship exists between all the vital forces, that they may be legitimately regarded as modes of one and the same force V And he also maintained that these so-called vital forces were evolved within the living bodies of plants and of the lower animals by the transformation of the light, heat, and chemical action obtained from without, which were given back to the external world again, either during the life of the living beings, or after their death, in terms of motion and heat, and also, to a slight extent, in the form of light and elec- tricity. These doctrines are thus definitely expressed by him 2 : c The vital force which causes the prim- ordial cell of the germ first to multiply itself, and then to develope itself into a complex and extensive organism, was not either originally locked up in that single cell, nor was it latent in the materials which are progressively assimilated by itself and its descend- ants 5 ; but it is directly and immediately supplied by 1 In unicellular organisms, all the vital functions, so far as they are differentiated, are carried on in the single cell ; and in the higher animals which proceed from the growth and development of some single, equally minute germ, specialization of function goes hand and hand with spe- cialization of structure. 2 Loc. cit. pp. 752-756. 3 This holds good for plants, the lowest animals, and the initial changes in the higher animals, though all the later vital manifestations of the latter are dependent almost entirely upon the redistribution of the forces pertaining to the organic substances which constitute their food, and to the various chemical changes taking place within their own C 2 20 THE BEGINNINGS OF LIFE. the heat which is constantly operating upon it, and which is transformed into 'vital force by its passage through the organised fabric 'which manifests it All the forces which are operating in producing the phenomena of life are in the first place derived from the inor- ganic universe, and are finally restored to it again. .... And there is strong reason to believe that the entire amount of force of all kinds received by an animal during a given period is given back by it during that period, his condition at the end of the time being the same as at the beginning. And all that has been expended in the building up of the organism is given back by its decay after death.' In plants and in the lower tribes of animals we are able to trace a most undoubted relationship between the vital activity of each individual and the amount of heat which it receives from external sources. Even bodies. Mr. Herbert Spencer says : ' We have next to note, as having here a meaning for us, the chemical contrasts between those organisms which carry on their functions by the help of external forces, and those which carry on their functions by forces evolved from within. If we compare animals and plants, we see that whereas plants, charac- terised as a class by containing but little nitrogen, are dependent upon the solar rays for their vital activities ; animals, the .vital activities of which are not thus dependent, mainly consist of nitrogenous substances. There is one marked exception to this broad distinction, however ; and this exception is specially instructive. Among plants there is a con- siderable group the Fungi many members of which, if not all, can live and grow in the dark ; and it is their peculiarity that they are very much more nitiogenous than other plants.' (Principles of Biology, 1864, vol. i. p. 37.) THE BEGINNINGS OF LIFE. 21 in 1837, M. Boussingault, after contrasting the meteor- ological circumstances in which wheat, barley, Indian corn, and the potato are developed at the equator and in the temperate zones, with their different rates of growth in these situations, came to the conclusion c that the same annual plant everywhere receives the same quantity of heat in the course of its existence.' And in one of his more recent works, speaking of the Fora- minifera, Dr. Carpenter says 1 , c We have found strong reason for regarding temperature as exerting a most im- portant influence in favouring, not merely increase in size, but specialization of development: all the most complicated and specialized forms at present known being denizens either of tropical or sub-tropical seas, and many of these being represented in the seas of colder regions by comparatively insignificant examples which there seems adequate reason for regarding as of the same specific types with the tropical forms, even though deficient in some of their apparently most important features/ That the rate of growth in plants depends most notably upon the amount of light and heat to which they are subjected is a fact familiar to most of us. The stimulation of the vital processes by heat is, indeed, most easy of demonstration in some cases. It is now perfectly well known that in Valisneria^ Chara^ Anacharls^ and other plants in the cells of which there is a well-marked cyclosis, the rate of revolution of the 1 'Introduction to the Study of the Foraminifera ' (Ray Soc.), 1862, p. 9. 22 THE BEGINNINGS OF LIFE. particles of protoplasm is, within certain limits, di- rectly dependent upon temperature. By variations of this, the rapidity of movement of the particles in the cell may be seen to be increased or diminished at pleasure. The amoeboid activity of a white blood corpuscle or of a pus corpuscle is similarly stimu- lated, within certain limits, by the influence of heat. We know also that the hatching of eggs and the germination of seeds may be likewise hastened or retarded by access or deprivation of heat. Considera- tions such as these at first suggested the doctrine of the Correlation of the Vital and the Physical Forces, a doctrine which has been slowly, though surely, gain- ing ground since the date of its first announcement. More and more evidence is gradually being accumu- lated in its favour, so that we now find Professor Frankland alluding to it in these terms: c No one possessing any knowledge of physical science would now venture to hold that vital force 1 is the source of muscular power. An animal, however high its or- ganization, can no more generate an amount of force capable of moving a grain of sand, than a stone can fall upwards, or a locomotive drive a train without fuel.' Mr. Herbert Spencer, also, speaking of the same doc- trine, says 2 , c It is a corollary from that primordial truth which, as we have seen, underlies all other truths, that 1 That is, any peculiar force existing of and I>y itself, independently of nil the physical forces. See Proceed, of Royal Institution, June 8, 1866. 8 ' Principles of Biology,' vol. i. p. 57. THE BEGINNINGS OF LIFE. 23 whatever amount of power an organism expends in any shape, is the correlate and c-ijuivalcnt of a power that was taken into it from without. On the one hand, it follows from the persistence of force, that each portion of mechanical or other energy which an organism exerts, implies the transformation of as much organic matter as contained this energy in a latent state. And on the other hand, it follows from the persistence of force that no such transformation of organic matter containing this latent energy can take place without the energy being in one shape or other manifested.' We shall find it worth our while, however, to follow up a little more fully the details of this most important doctrine, as it will aid us so much in forming a true conception as to the nature of Life. As pointed out by M. Gavarret l , most of the physi- cal force which, in the form of light and heat, impinges upon a plant, is consumed therein (travail mttrleur}. It is stored up as potential force in the complex organic substances entering into the composition of the plant ; these being produced therein (under the influence of the already existing living tissues) by the action of physical forces upon the not-living constituents of the earth, air, and water by which the plant was surrounded. The animal, on the contrary, liberating and using these forces which have been stored up by the plant after assimilating its substance in the form of food expends them in the production of that travail ext'crieur which 1 ' Ph5nomoncs Physiques cle la Vie,' 1869, Paris p. 73. 24 THE BEGINNINGS OF LIFE. the animaFs nature and the necessities of its existence compel it to manifest. Animals display, in varying proportions, three principal modes of vital activity which testify to the continual liberation of force within them : (i) they appear to produce heat; (2) they move, by reason of the contractility of certain tissues ; and (3) they display certain nervous phenomena. i. Very many animals constantly maintain them- selves at a temperature above that of the medium in which they live; this being more especially the case with the so-called warm-blooded animals amongst which birds are most remarkable for the very great difference existing between their temperature and that of the air. The cause of this difference in temperature between the animal and its medium has been variously explained at different times. It was believed by Galen that heat was actually produced de novo in the left ventricle of the heart ; and even John Hunter thought that the pro- duction of animal heat depended upon a special vital force or principle, which was able not only to produce but actually to destroy heat. Others and that even in comparatively recent times have striven to prove that some principle resident in the nervous system was capable of giving rise to animal heat. The true theo- ries on this subject, however, may be said to date as far back as the close of the eighteenth century, and to have commenced with the brilliant discoveries of Lavoi- sier. Speaking of his researches, M. Gavarret says 1 : 1 Loc. cit. p. 99. THE BEGINNINGS OF LIFE. 25 c The alimentary substances introduced into the stomach, after being digested and liquified, are absorbed and sent into the vessels, where they mix with the blood , on the other hand, the air introduced at each inspiration into the pulmonary cavity yields to the blood a part of its oxygen. Struck with this double centripetal move- ment., Lavoisier asked himself what happened to these substances brought into relation with one another within the blood-vessels. Proceeding in this research with all the rigour of a chemical analysis, he showed that the oxygen introduced by the respiratory passages attacks the organic substances furnished by digestion, burns them, combining with their carbon and their hydrogen to form carbonic acid and water. He showed that this slow combustion of the organic materials of the blood is an incessant source of heat V Lavoisier then instituted experiments to determine the quantity of heat abstracted from the animal by radiation, by contact with air, and by evaporation of fluids from the surface of the body. On the other hand, he measured the quantity of oxygen consumed, calculated the propor- tions of carbonic acid and of water produced by the combination of this oxygen with the materials of the blood, and then estimated the quantity of heat dis- engaged during these reactions. From a comparison of the results thus obtained in these two series of ob- servations, he came to the conclusion that the chemical reactions carried on within the body would furnish 1 ' Mm. de 1'Acad. des Sciences,' 1789. 26 THE BEGINNINGS OF LIFE. enough heat to maintain the animal at its proper tem- perature. This conclusion was afterwards confirmed by many other experiments and observations. The re- searches of Lavoisier still left us in doubt, however, as to whether the combustion of the materials of the blood took place in the capillaries of the body generally, or in those of the pulmonary circulation. This doubt was removed by Spallanzani; and the subsequent experi- ments of Magnus and of Claude-Bernard only tended to confirm his conclusion, that the heat-producing chemi- cal changes were carried on in the capillaries of the body generally. Thus the heat evolved in animals is some of that solar heat which had previously impinged upon plants, and which was gradually locked up in the form of potential force, during the growth of the plant- tissue subsequently taken as food by animals. 2. Turning now to the next dynamic manifestation of animals to their power of movement we may, for the sake of brevity, consider this as it presents itself in the higher animals only in those in which the movements depend upon the contractility of definite structures known as c muscles.' Contractility is the essential attri- bute of the muscle, and, being one of the peculiarly vital endowments, we may now enquire how far this vital property is one which is correlatable with ordinary physical forces, or whether it can display itself inde- pendently of these l . In the first place, it is important 1 For a full and admirable treatment of this question we must Tefer the reader to pp. 120-194 of the work of Gavarret, already quoted. THE BEGINNINGS OF LIFE. 27 to state that this contractility of the muscle can be ex- cited, for a time, after the death of the animal of which it formed part : the length of time during which the property persists being, generally, longer in proportion as the animal is lower in the scale of organization. During winter the muscles of certain fish and reptiles have been known to contract for a week after death, though in mammals and birds this property of the vo- luntary muscles disappears after a few hours. From the researches of Nysten upon the bodies of decapitated criminals, it appears that in man, as in the lower ani- mals, a certain order is observed amongst the different muscles of the body in the loss of this vital property. Contractions, from electrical stimuli, ceased in the left ventricle of the heart after forty-five minutes; in the muscles of the extremities after seven hours ; and, last of all, in the right auricle of the heart, which, on this account, had been previously spoken of by Galen as c ultimum moriens/ In one instance, Nysten found that this portion of the human heart could be made to contract i6j hours after the death of the individual. Contractility of the muscle cannot, therefore, be due to any peculiar c vital principle' which leaves the body when the organism dies. Although the muscle is usually excited to contract by a stimulus sent through a nerve, we have now learned principally through the phenomena observable in ani- mals poisoned by woorara that the contractility of the muscle may be called into play through the direct 28 THE BEGINNINGS OF LIFE. action of a stimulus, and without any intervention of the nervous system. The contractility is, however, closely related, and more or less proportionate in degree, to the supply of arterial blood circulating in the capillary vessels with which it is furnished. The experiments of Longet l on this subject are most instructive. He found, as a result of experimentation upon many ani- mals, that all traces of contractility after the direct application of a stimulus disappeared from muscles which had received no arterial blood for a space of two hours ; but that almost as soon as the afflux of arterial blood to the muscle was again permitted even in the space of a few minutes the contractility of the muscles again manifested itself upon the application of a stimu- lus, either direct or indirect. But those heat-liberating chemical reactions the processes of combustion neces- sary for the continuance of the nutritive changes are carried on in the capillaries of the muscle as well as in the capillaries of other parts of the body ; and it would seem that the disappearance of the property of contrac- tility from the muscle is dependent upon that stoppage of the heat-evolution therein which the arrest of the circulation entails. In support of this view, on the one hand, it has been shown by M. Becquerel 2 that the temperature of a muscle becomes sensibly lowered when the artery supplying it is compressed ; and, on the other^ de Physiologic,' sme ed. 1869, t. ii. p. 613. 2 ' Ann. de Chimie de Physique,' 1835, t. lix. p. 135,. THE BEGINNINGS OF LIFE. 29 we learn, from the experiments of Matteucci l y that the activity of the processes of combustion within the muscle increase during its contraction -. Many separate sets of investigations do indeed tend to show that an excess of heat is developed during mus- cular activity, though, on the other hand, there is evi- dence to prove, from the highly interesting experiments of M. Beclard 3 , whose results have been confirmed and extended by M. Heidenhain, the increase in the acti- vity of the chemical changes which undoubtedly exists during muscular exercise, is much greater than can be accounted for by the actual increase of sensible heat in the body. After alluding to these various investigations, M. Gavarret generalizes their results as follows 4 : 1 ' Letture sul 1' elettro-physiologia,' Milano, 1867, p. 36. 2 During a state of rest, or moderate exercise, combustion and eli- mination of its products are duly regulated in the muscle. So long as this balance is maintained the muscle preserves its physiological pro- perties, and the chemical reaction of its juice remains neutral or alkaline. But when excessive activity of the muscle is maintained, then the pro- cesses of elimination can no longer keep pace with those of combustion : lactic acid accumulates within the muscle, and the reaction of its juice becomes decidedly acid. The contractility is gradually enfeebled by the increasing accumulation of these effete products within the muscle, and the feeling of fatigue is induced. There is good reason for believing that this feeling of fatigue is rather dependent upon the accumulation of these products of combustion within the muscle than upon an actual molecular wasting of the muscle-substance. There is, however, a more general feeling of fatigue which is dependent rather upon state of nerv- ous system than state of muscle. 3 ' De la Contraction musculaire dans ses rapports avec la temperature animale,' Paris, 1861. 4 Loc. cit. p. 135. 30 THE BEGINNINGS OF LIFE. c All these experiments agree in showing that in the muscular system of an animal which accomplishes ac- tual work (such as raising a weight, dragging a load, &c.) everything goes on as in an ordinary steam-engine. Whilst the muscle performs work, the heat produced by the internal combustions becomes divided into two complementary portions; the one part appears as sen- sible heat, and determines the temperature of the muscle, the other disappears^ so far as its existence in the form of heat is concerned, and, by the intervention of the muscular contraction, becomes transformed into mechani- cal work. The muscle is an animated machine^ which, like the steam-engine, utilizes the heat in order to produce work : in both cases there is necessarily an equivalence between the heat which disappears, or is consumed, and the external work achieved.' In con- sideration of its origin, the energy manifested during the contraction of the muscle is directly comparable with the energy due to the elasticity of vapour when this is the motor power at work, as in a steam-engine. Chemical change combustion, in fact in each case, in muscle and steam-engine alike, causes the liberation of heat; and in each case part of this liberated force is capable of manifesting itself anew in the form of me- chanical energy. It matters not whence the heat is derived whether it comes from the decomposition of the recently assimilated food-products in the blood which circulates through the muscle, or whether it proceeds from the liberated energy or sun-force that THE BEGINNINGS OF LIFE. 31 may have been locked up for ages in the bowels of the earth, but which is now set free by a process of com- bustion in the engine fire the result is the same, and in the muscle, as much as in the steam-engine, we have to do with a machine in which the transference of heat into mechanical energy is capable of being effected. The muscle, it is true, is a much more subtle kind of machine, and the precise mode of its action is as yet hidden from us ; we know not hoA matter, remove particular atoms of ponderable matt eiv> from* their attachments, and carry them within reach of other attachments Now the discoveries of Bunsen and Kirchoff respecting the absorption of particular lumi- niferous undulations by the vapours of particular sub- stances, joined with Professor Tyndall's discoveries respecting the absorption of heat by gases, show very clearly that the atoms of each substance have a rate of vibration in harmony with ethereal waves of a certain length, or rapidity of recurrence. Every special kind of atom can be made to oscillate by a special order of ethereal waves, which are absorbed in producing its oscillations and can by its oscillations generate this same order of ethereal waves. Whence it appears that immense as is the difference in density between ether and ponderable matter, the waves of the one can set the atoms of the other in motion, when the successive H 2 100 THE BEGINNINGS OF LIFE. impacts of the waves are so timed as to correspond with the atoms. The effects of the waves are, in such case, cumulative; and each atom gradually acquires a momentum made up of countless infinitesimal mo- menta. 3 Mr. Spencer then points out that the elements of a chemically-compounded atom (or c molecule/ as it is usually termed by chemists), being still free to move within certain limits, we must suppose them to remain severally capable of vibrating in unison with the same kinds of ethereal waves, as were capable of moving them when they were in their uncombined condition. The component atoms, therefore, retain their original rates of oscillation, modified only as they may be by their mutual influence upon one another j whilst the compound atom or molecule will have a capacity of oscillating determined by the attributes of its con- stituent atoms. Taking the case of binary molecules as an example, it becomes evident that if the members of such molecules differ from one another considerably, they are almost sure to be thrown into different rates of vibration, and c it is manifest that there must arise a tendency towards the dislocation of the two a tendency which may or may not take effect, according to the weakness or strength of their union, and according to the presence or absence of collateral affinities? This inference is perfectly in harmony with certain known facts. The metallic compounds which are most de- composable under the influence of the chemical rays of light are silver, gold, mercury, and lead, all of which THE BEGINNINGS OF LIFE. IOI have high atomic weights, whilst others, -such as so- dium and potassium, the atomic weights of which are low, are much less changeable. In binary compounds of these several metals having high atomic weights there would be a greater difference between the weights of the component elements, than if we had to do with compounds of the small-atomed metals, and so also, it has been found that it is precisely those compounds which consist of the most dissimilar elements that are the most decomposable. But there is also another most interesting aspect of the question. Mr. Spencer says : c Strong confirmation of this view may be drawn from the decomposing actions of those longer ethereal waves which we perceive as heat. On contemplating the whole series of binary compounds, we see that the elements which are most remote in their atomic weights, as hydrogen and the noble metals, will not combine at all : their vibrations are so unlike that they cannot keep together under any conditions of tempe- rature. If again we look at a smaller group, as the metallic oxides, we see that whereas those metals that have atoms nearest in weight to the atoms of oxygen, cannot be separated from oxygen by heat, even when it is joined by a powerful collateral affinity; those metals which differ more widely from oxygen in their atomic weights, can be de-oxidized by carbon at high temperatures; and those which differ from % it most widely, combine with it very reluctantly, and yield it up if exposed to thermal undulations of moderate 102 THE BEGINNINGS OF LIFE. intensity. And here indeed, remembering the relations between the atomic weights in the two cases, may we not suspect a close analogy between the de-oxidation of a metallic oxide by carbon under the influence of the longer ethereal waves, and the decarbonization of car- bonic acid l by hydrogen under the influence of the shorter ethereal waves ? ' These discoveries and suggestions are, we think, of the deepest interest and importance. They open up possibilities of explaining problems which had hitherto seemed well-nigh insoluble, and that, too, in the sim- plest way, and by the application of strictly physical principles. Having to deal with such mutable ma- terials as the unstable and big-atomed colloids, and being aware of the above-mentioned explanations as to the way in which vibrations communicated to an imponderable ether may bring about motions amongst the atoms of ponderable matter, much of the seem- ingly impenetrable mystery which has hitherto en- shrouded the nature of the changes taking place in living tissues, appears to be notably lessened. No subject seemed more hopelessly difficult, and yet we can now only agree with Mr. Spencer when he says : c These conceptions help us to some dim no- tion of the mode in which changes are wrought by 1 The decomposition of carbonic acid and the fixation of carbon as one of the component elements of living tissue is continually taking place in the leaves of plants under the stimulus of solar light and its actinic rays. THE BEGINNINGS OF LIFE. 103 light in the leaves of plants. Among the several elements concerned there are wide differences in mole- cular mobility, and probably in the rates of molecular vibration. Each is combined with many of the others, but is capable of forming various combinations with the rest. And they are severally in presence of a com- plex compound into which they all enter, and which is ready to assimilate to itself the new compound atoms that they form. Certain of the ethereal waves falling on them when thus arranged, there results a detachment of some of the combined atoms and a union of the rest. And the conclusion suggested is, that the Induced vibrations among the various atoms as at frst arranged } are so incongruous as to produce instability , and to give collateral affinities the power to 'work a re- arrangement ivhich^ though less stable under other conditions^ is more stable in the presence of these particular undulations? Thus the way seems opening for us to comprehend how, under the mere influence of physical forces, not- living combinations may be broken up so as to give place to those more subtle combinations of matter which are only possible where much incident force is retained. We know that the food of plants consists of not-living or so-called mineral ingredients, we know also that the plant grows, and therefore that these non-living ingredients must be decomposed in order to give place to the new living matter which is continually being produced. Physical forces and natural affinities are, therefore, supposed to be the 104 THE BEGINNINGS OF LIFE. only factors necessary for bringing about this marvel- lous transformation, for enabling Living Matter to originate in the tissues of plants by means of a complex rearrangement of pre-existing not-living elements. To some these views concerning the nature of Life and vital manifestations may seem to be sadly insuffi- cient, reducing it, as the theory does, to a mere inter- play between a material aggregate of a particular kind and its environment. But, it must not be forgotten that the only fair way, in judging of the adequacy of such an hypothesis, is to consider how far it is applicable as an explanation of the phenomena exhibited by the lowest Living Things. The more we look to the higher forms of Life, the more apt are we to be blinded to the real and essential nature of the phenomena taking place, owing to the greater complexity which has arisen in their various functions step by step with the struc- tural differentiation of the organism itself. Never- theless, even from phenomena presented by some of these higher organisms, evidence may be obtained which is certainly more reconcilable with the con- ceptions of Life to which we have just been alluding than with any other. When seeds of wheat, produced by living plants in times antecedent to the Pharaohs, can remain in the Egyptian catacombs, through century after century displaying of course no vital manifestations, but never- theless retaining the potentiality of growing into per-. THE BEGINNINGS OF LIFE. 105 feet plants 1 whenever they may happen to be brought into contact with suitable external conditions, we must presume that, either (i) during this long lapse of cen- turies the 'vital principle' of the plant has been imprisoned in the most dreary and impenetrable of dungeons, whither no sister effluences from the general c soul of nature ' could affect it, and whence escape was impossible; or else (2) that the germ of the future possible living plant is there only in the form of an inherited structure whose molecular complexities are of such a kind that, after moisture has restored mobi- lity to its atoms, its potential life may pass into actual life, because the ever-recurring ethereal pulses of motion, and other changes in its environment, are capable of giving rise to a definite series of simultaneous and successive changes in its own structure. This series of actions and re-actions most variously complex though they may be constitute the essential phenomena of Life, and the structure of the organism or living thing manifesting them is but the material embodi- ment resulting from such actions. 1 In connection with periods of rest in Plant life, Alex. Braun (Re- juvenescence in Nature, Syd. Soc. 1853, p. 200, et seq.) makes some very interesting remarks. We will extract the following sentences only: ' The formation of fixed oil is intimately connected with that of starch in the economy of cell-life ; its appearance, in like manner, announces the repose of age in cell-life, its disappearance the beginning of Re- juvenescence. We meet with fixed oil in the cells, either mixed with starch, substituted for it, or gradually displacing it; its occurrence is perhaps still more general than that of starch, since it exists even in the Fungi and Phycochromiferous Algae,' io6 THE BEGINNINGS OF LIFE. But such things are not only true concerning the germs of plants ; somewhat parallel phenomena are pre- sented even by adult organisms in the animal series. The c Sloths ' of Spallanzani, the Rotifers, and the Free Nematoids or Anguillules, certainly should be taken into account by those who would wish to arrive at correct conceptions as to Life. These animals, having com- paratively definite and complex organizations, are now FIG. i. Animals found in tufts of Moss and Lichen. a. Plectus parietinus, a Free Nematoid. b. Rotifer vulgaris, the common Wheel Animalcule. c. Emydium testudo, one of the ' Sloths ' of Spallanzani. notorious for their tenacity of Life, their power of re- sisting the most adverse external conditions, and, above all, for their power of resuming active vital mani- festations, after these have been completely in abeyance for five, ten, fifteen, or even more than twenty years ' . 1 More complete details concerning these properties may be found in a memoir on ' The Anatomy and Physiology of the Nematoids, Parasitic THE BEGINNINGS OF LIFE. IO/ Living together, as they generally do, tenanting the same tufts of moss or the same patches of lichen, they eke out their existence by instalments, instead of enjoy- ing a more or less definite and continuous span of life. And, during their most extreme degrees of desiccation they certainly can have no more title to be looked upon as living things than can the seeds in the cata- combs of Egypt. Though not living, they also retain the potentiality of manifesting Life: and, for each alike, in order that this potentiality may pass into an actuality, the first requisite is water, with which to restore to them that possibility of molecular re-arrange- ments under the influence of incident forces, of which the absence of water had deprived them, and without which Life, in any real sense, is impossible 1 . and Free.' Philosophical Transactions, 1866, p. 613-620. With regard to Nematoids I have there said that ' the remarkable tenacity of Life of which we have been speaking is met with only amongst the repre- sentatives of four land and freshwater genera, Tylencbus, Plectus, Aphelencbus, and Cepbalobus ; whilst those of all the other genera, except- ing Rhabditis, marine as well as land and freshwater, are rather remark- able for the very opposite characteristic, they being incapable of recovery even after the shortest periods of desiccation.' It was formerly supposed that all the Free Nematoids exhibited this tenacity of Life. 1 Professor Owen says (Monthly Microscopical Journal, May i, 1869, p. 294), 'There are organisms (Vibrio, Rotifer, Macrobiotus, &c.) which we can devitalize and revitalize devive and revive many times. As the dried animalcule manifests no phenomenon suggesting any idea contributing to form the complex one of " life " in my mind, I regard it to be as completely lifeless as is the drowned man whose breath and heat have gone and whose blood has ceased to circulate The change of work consequent on drying or drowning forthwith begins to alter relations or " composition," and, in time, to a degree 108 THE BEGINNINGS OF LIFE. But the Death of organisms is even capable of teach- ing us something as to their life : their mode of dying is typical of their mode of living. The more highly developed an organism has become, the more has speci- alization been brought about in the functions of its several parts, and (in almost the same proportion) the more has the all become welded into a whole. The greater the degree of interdependence existing between the actions of its several parts, the more is the well- being of the entire organism interfered with by damage occurring to any one of these principal parts. Through the intervention, for the most part, of the nervous system and the vascular system, this individuality of the entire organism is carried to the most marked extent in the highest vertebrata, so that the Life of one of these creatures regarded as a whole, or sum total of phenomena differs almost as widely as it is possible from that of some of the lowest animals on the one hand, and from that of plants on the other. Their mode of death also is quite different. And as with Life, so is it with Death, we are perhaps too apt to form our notions concerning each from what we see taking place in man himself and in the higher living things many people apparently never reflect upon the striking differences which are presented, in this respect, by the lowest animals as well as by the members of the adverse to resumption of the vital form of force, a longer period being needed for this effect in the Rotifer, a shorter one in the Man, still shorter, it may be, in the Amoeba,' THE BEGINNINGS OF LIFE. 109 vegetable kingdom. In man we find a fully developed and almost inconceivably complex organism; in the working of which, as in that of any ordinary but ex- tremely complex piece of machinery, there is seen to be the closest interdependence between the actions of the several parts. Destined as a whole to perform a certain work, we may constantly see, for instance, in the wool-factories of our manufacturing districts a piece of machinery in which the sum total of work to be done is parcelled out amongst different re- lated and interdependent parts wheels of every de- scription, large and small, plain and toothed ; combs of various kinds; rhythmically acting knives, reels and thread twisters, all combine simultaneously or suc- cessively to elaborate the woof out of which our gar- ments are woven. The action of some parts are more essential, that of others less essential to the action of the machine as a whole. An interference with the revolution of some central wheel may suffice instantly to interrupt the working of the entire mechan- ism, just as the functional workings in the body of a highly organized vertebrate animal may be as sud- denly arrested by a puncture in a particular part of its nervous system. In both instances the first result is a simple cessation in the action of a complex machine ; and, in the case of the animal seeing that its body has been gradually built up in a given manner under the influence of certain definite actions or functions, the continuance of which is absolutely necessary it 1 1 THE BEGINNINGS OF LIFE. follows that when such actions are arrested irretrievably, the organism as an individual whole must die, although its separate parts and anatomical elements may and do perish much more slowly, after different intervals. These perish simply by default because the conditions suitable for the continuance of their life are no longer forthcoming ; and not because they themselves as vital units had received any damage at the time that the organism as a whole ceased to live when the action of the vital machine was stopped. Every anatomical ele- ment of even the highest animal may fairly be said to possess Life and a specific mode of action, each after its own kind ; only, the vital manifestations of the whole of these units are subordinated to the Life and, in health, work towards the well-being of the higher organism of which they form part. The death of the Organism as a whole, results from the stoppage of its machinery ; but the death of its component parts subsequently follows as a consequence of the cessation of those more general actions under whose influence they were produced, and without whose existence they can no longer live. If the medulla oblongata has been punctured and the heart has ceased to beat, there is a permanent stoppage of this function, without which Life, in such a being as a mammalian vertebrate, is impossible. It consequently dies. If the blood no longer circulates, the anatomical elements, which are absolutely dependent upon this fluid for their pabulum, must also, after. a time, necessarily die. The individual THE BEGINNINGS OF LIFE. in muscular and nervous elements may and do still live for a time the nerve will conduct a stimulus under which the muscle will contract; and so is it, even more markedly, with the epithelial cells those pos- sessing cilia display their characteristic vital actions long after the organism considered as a complex whole has ceased to live. Now the lower we descend in the scale of living things, the less marked does the life of the organism as a whole become, in contradistinction to the life of its several parts. The c tendency to individuation ' be- comes less and less manifest in proportion as the struc- tural differentiation diminishes. The more the several parts of an organism resemble one another, the less difference is there between the functions discharged by these several parts, and therefore the importance is proportionately less to the whole organism when one of these functions is interfered with. This is but saying, in other words, that the machinery of Life grows less and less complex, and that we are gradually ap- proximating more and more to a state of things in which, to employ the same simile, we have a mere aggregate of wheels, a mere repetition of more or less similar parts, with progressively less of mutual inter- dependence between their several actions. Who has not noticed the slowness with which a serpent dies, how the toad clings to Life ? Look at the writhing segment of the worm whose body has been cut by the gardener's spade, or at the green Nereis of the 1 12 THE BEGINNINGS OF LIFE. rock-pool whose body has been accidentally torn, and let us think of the powers of repair possessed by each it is not killed, and an attempt will be made more or less effectually to reproduce the lost parts, just as a crystal, in its own proper medium would, after injury, tend to reproduce its original symmetry of form. Look again at the little polyp of our lakes and ponds the Hydra, whose individual Life is so dwarfed in com- FIG. 2. Hydra viridis in different stages of extension and contrac- tion, reproducing gemmiparously attached to roots of Duckweed. (Roesel.) parison with the Life of its several parts that you may cut it or injure it to almost any extent, and yet the separate parts will still live \ It can, in fact, scarcely 1 It has, moreover, been recently revealed by the experiments of Haeckel that a similar power of reproduction, previously unsuspected, is possessed by Medusae. Haeckel says : ' My experiments proved that it prevails to an amazing extent in many medusae, especially in those be- THE BEGINNINGS OF LIFE. 113 be said to constitute a living whole, for the one animal may be divided into two, and the two into four, and each part will grow into an organism like that of which it is a segment the parts grow into wholes, and in the place of the one individual organism we get four others similar in kind. By mechanical injury or compression we may destroy any single part so compressed, but we do not affect the total organism, except for a time : the lost part is reproduced. These also are the kinds of phenomena and modes of Life with which we are familiar throughout the Vegetable Kingdom nowhere do we meet with any- thing like that same amount of integration or indi- viduation which is characteristic of the higher animals. Mere fragments of plants in the form of buds, c cut- tings,' or portions of the root, separated from the parent organism, are capable of reproducing plants similar to those from which they have been derived. The c tendency to individuation' exists here also, but even in the most perfect plant the accomplished result is small indeed, when compared with what we encounter amongst animals. The absence of a nervous system longing to the family Tbaumantiadte of Gegenbauer (Laodicei of Agassiz). In several species of this family I could divide the umbrella into more than a hundred species ; and from each, provided it only contained a portion of the margin of the umbrella, grew in a few days (from two to four) a complete small medusa. Merely a loosened shred of the fringe on which the base (the adjoining piece of the edge of the umbrella) remained, formed a medusa in a few days.' ' Monograph of Monera.' Transl. in ' Quart. Journal of Micros. Science,' April, 1869, p. 117. I 114 THE BEGINNINGS OF LIFE. however, combined with the less perfect condition of the vascular system, are sufficient to account for this want of integration in the plant, and the great amount of independence shown by its individual parts. Such are some of the principal differences in the nature of the Life, or aggregate vital manifestations of the members of the Animal and of the Vegetable King- doms: and great as are the differences between the phenomena of the higher and of the lower forms of these, we may look for even still lower manifestations of Life in a group of organisms whose characteristics, whether structural or functional, are so little marked as to make the most philosophic naturalists unable to assign them a place amongst either the one or the other of these Organic Kingdoms. It might have been expected, in accordance with the doctrines of Evolution, that the lowest living things would present characters of the most general descrip- tion. They ought to be simply living things, without visible organization, and should as yet present no special characters by virtue of which a place might be assigned to them either in the vegetable or in the animal kingdom. The older naturalists thought that every living thing must be either an animal or a plant, and they accordingly ranged all organic forms under one or other of these categories. But there were certain of them whose characteristics were so in- definite that they could really claim for themselves no THE BEGINNINGS OF LIFE. 115 place in either of these kingdoms, and they were con- sequently placed in the one or in the other alternately as the state of knowledge at the time varied, or almost according to the whim of successive writers. But now, at last, after this unseemly bandying to and fro, their proper position is being generally recognized. The merit of taking a definite step as regards the classifica- tion of these animals rests with Professor Haeckel, who says 1 : C I have made the attempt in my "General Morphology " to throw some light upon this systematic chaos, by placing, as a special division between true animals and true plants, all those doubtful organisms of the lowest rank which display no decided affinities nearer to one side than to the other, or which possess animal and vegetable characters united and mixed in such a manner that, since their discovery, an in- terminable controversy about their position in the animal or in the vegetable kingdom has continued. Manifestly this controversy becomes reduced to the smallest compass if the disputable and doubtful inter- mediate forms are separated for the present (though only provisionally) both from the true animals and from the true plants, and united in a special organic "kingdom." Thereby we obtain the advantage of being able to distinguish both true animals and true plants by a clear and sharp definition, and, on the other hand, a special proportion of attention is attracted 1 ' Monograph of Monera.' Translation in ' Quarterly Journal of Microscopical Science,' July, 1869, p. 230. I 2, Il6 THE BEGINNINGS OF LIFE. to the very low organisms hitherto so much neglected, and yet so extremely important. I have called this boundary kingdom intermediate between the animal and the vegetable kingdoms, and connecting both, the PROTISTA i.' All the members of this king- dom multiply by an exclusively non-sexual method of reproduction. It should be understood, however, that in proposing such a classification Prof. Haeckel by no means wishes to establish an absolute wall of separation between these three organic kingdoms. He is much more disposed to believe that animals as well as plants have gradually arisen out of mo- difications which have taken place in the simplest Protista. This primordial organic kingdom he divides into ten groups, in the lowest of which, named Monera 2 , are included such mere naked, non-nucle- ated jelly-specks as those belonging to the genera 1 rb irpduTtaTov, the first of all, primordial. 'Gen. Morph.' vol. i. p. 203, and vol. ii. p. xx. and p. 403. Elsewhere he says : ' The question which has been so often debated during the last twenty years as to a boundary between the animal and the vegetable kingdoms will be decided by the Monera, or, more correctly, they will prove that a perfect separation of both kingdoms, in the manner in which it is usually attempted, is impossible. The Monera are apparently such peculiar organisms that they can be classed with equal propriety, or rather with equal arbitrariness, as primitive animals or as primitive plants. They may just as well be regarded as the first beginnings of animal as of vegetable organization. But as no one mark of distinction inclines them more to one side than to the other, it seems most correct at present to class them as intermediate between true animals and true plants.' .('Journal of Micros. Science,' Jan. 1869, p. 29.) 2 Name from ftof^s, simple. THE BEGINNINGS OF LIFE. 117 Protamoeba and Protogenes, to which we shall have occa- sion again to allude. The other members of this primitive kingdom being comprised under one or other of the following groups : Flagellata, Labyrinthulea, Diatomea, Phycochromacese, Fungi 1 , Myxomycetes, Proto- plasta 2 , EToctilucsD, and Rhizopoda. The homogeneous and shapeless masses of plasma constituting the group Monera are supposed by Prof. Haeckel to have come into being by a process of equivocal or ' spontaneous ' generation, and these are regarded by him as the primordial living things 3 . We think, however for reasons which will subse- quently appear that, side by side with these, should stand Bacteria, Torul^ and other equally primordial forms not alluded to by Prof. Haeckel. We merely mention this conclusion at which we have arrived, but will not enlarge upon it at present. It will be useful for us to see, however, what Prof. Haeckel has to say concerning the members of his group Monera, including as it does the two genera above mentioned, as well as others (such as Protomyxa and Vampyrella] the species of which are no longer naked, 1 In justification of the removal of these from the Vegetable Kingdom Haeckel says : ' The whole method of nourishment and assimilation of the fungi, in connection with many other characters (especially the total absence of chlorophyll), remove them so far from the true plants that the earlier botanists long since wished to establish for the fungi a special organic kingdom.' 2 In this group are included all the higher nucleated Amoeba. 3 Loc. cit. p. 330. Il8 THE BEGINNINGS OF LIFE. but are bounded by an outer membrane 1 . He says 2 : C I have called those forms of life standing at the lowest grade of organization Monera. Their whole body, in a fully developed and freely moving con- dition, consists of an entirely homogeneous and struc- tureless substance, a living particle of albumen 3 , capable of nourishment and reproduction. These simplest and most imperfect of all organisms are, in many respects, of the highest interest. For the albumen- like organic matter meets us here as the material substratum of all life phenomena^ apparently not only under the simplest form as yet actually observed, but also under the simplest form which can well be imagined. Simpler and more incomplete organisms than the Monera cannot be conceived. . . . Indeed, the whole body of the Monera, however strange this may sound, represents nothing more than a single, thoroughly homogeneous particle of albumen, in a firmly adhesive 1 Professor Haeckel proposes that the word ' Sarcode,' introduced by Dujardin, should be applied to the free protoplasm which exists without a covering or limiting membrane, only with the distinct understanding that such free protoplasm differs in no essential respect from that which is encapsuled, whether it is marked off from surrounding things by a mere limiting membrane, or whether it is enclosed within a definite cell-wall. 2 Translation in 'Journal of Micros. Science,' Jan. 1869, p. 28. 3 ' In all chemical and physical respects,' Prof. Haeckel writes else- where, ' this substance shows the qualities of a consistent carbonaceous compound of the group of albuminous substances (Proteine). It is identical with the substance which as Plasma or Protoplasm forms the contractile living substance of all organic Plastides, of all cells, and cytodes of animals, protista, and plants.' THE BEGINNINGS OF LIFE. 119 condition. The external form is quite irregular, con- tinually changing, globularly contracted when at rest. Our sharpest discrimination can detect no trace of an internal structure, or of a formation from dissimilar parts. As the homogeneous albuminous mass of the body of the Moner does not even exhibit a differen- tiation into an inner nucleus and an outer plasma, and as, moreover, the whole body consists of a homo- FIG. 3. Representatives of Haeckel's group Monera. a. Most minute specks of protoplasm from fine surface mud of fresh- water ponds, Hendon. ( X 800.) b. Prot amoeba primitiva (Haeckel). Two individuals resulting from a recent fission. c. Vampyrella pendula (Cienkowski). d. Amoeba porrecta (Max Schultze). This is really a Protamceba. e. Protomyxa aurantiaca (Haeckel) developed into a ' plasmodium/ either from the simple increase of a single amreba-like germ or by the union of several originally distinct individuals. A devoured Isthmia and a Navicula are visible in the homogeneous parenchyma of the sarcode ; also numerous vacuoles. (6, c, d, and e x 220.) geneous plasma, or protoplasma, the organic matter here does not even reach the importance of the simplest 120 THE BEGINNINGS OF LIFE. cell. It remains in the lowest imaginable grade of organic individuality.' Professer Haeckel afterwards says: c The Monera are indeed Protista. They are neither animals nor plants. They are organisms of the most primitive kind: among which the distinc- tion between animals and plants does not yet exist. But the term " organism" itself seems scarcely ap- plicable to these simplest forms of life; for in the whole conception of the "organism" is especially implied the construction of the whole from dis- similar parts, from organs or limbs. At least, two separate parts must be united to complete the descrip- tion of a body as an organism in this original sense. Every true Amceba, every true (i. e. nucleus-including) animal and vegetable cell, every animal-egg, is, in this sense, already an elementary organism, composed of two different organs, the inner nucleus and the outer cell-matter (Plasma or Protoplasma) . Compared with these last the Monera are strictly " organisms without organs." Only in a physiological sense can we still call them organisms ; as individual portions of organic matter, which fulfil the essential life-functions of all organisms, nourishment, growth, and reproduction. But all these different functions are not yet limited to dif- ferent parts. They are all, still, executed equally by every part of the body V 1 Prof. Haeckel then continues : ' If the natural history of the Monera is already, on these grounds, of the highest interest as well for morphology as for physiology, this interest will be still more increased THE BEGINNINGS OF LIFE. 121 One of the most rudimentary, and at the same time the first member of this group observed by Prof. Haeckel, he named Protamceba primitiva. c l observed it/ he says, c for the first time at Jena, in the summer of 1863, in water which I had brought from a small pond in the Tautenburg forest (opposite Dornburg, on the right bank of the Saal). The bottom of this shallow little pond is thickly covered with fallen decayed beech- leaves, and in the fine brown mud, among the decayed leaves, I found the little Protamceba.' It was a minute plasma-ball, perfectly homogeneous, rather more than Y-Q^ of an inch in diameter, which moved with extreme slowness, and also changed its form as slowly, by means of alternate protrusions and retractions of bluntly rounded portions of its body-mass. The whole sub- stance of Protamceba primttwa is absolutely structureless and homogeneous. At one time it will multiply itself by a process of fission, whilst, at another time, individuals by the extraordinary importance which these very simple organisms possess for the important doctrine of spontaneous generation or arche- gony. I have shown in my " General Morphology " that the accepta- tion of a genuine archegony (once or repeated) has at present become a logical postulate of scientific natural history. Most naturalists who have discussed this question rationally believed that they must designate simple cells as the simplest organism produced thereby, from which all others developed themselves. But every true cell already shows a division into two different parts, i. e. nucleus and plasma. The imme- diate production of such an object from spontaneous generation is obviously only conceivable with difficulty; but it is much easier to conceive of the production of an entirely homogeneous, organic sub- stance, such as the structureless albumen body of the Monera.' 122 THE BEGINNINGS OF LIFE. originally separate coming into contact accident- ally, unite or fuse together into a single individual. The blunt projections of its body-mass, by means of which it is continually varying in form, contrast notably with the fine thread-like prolongations, occasionally interlacing, which are thrown out from Max Schultze's nearly allied Amoeba porrecta. These latter projections, or pseudopodite, as they have been termed, closely resemble those met with in the shelled-amcebse or Foraminifera l . But even in 1857 an organism was procured from great depths in the Atlantic Ocean by Captain Dayman, which ought, apparently, to be placed in this same group Monera. This and other products of Captain Dayman's expedition were examined by Pro- fessor Huxley, and since the publication of HaeckeFs Memoir, he has proposed to look upon this organism as a c Moner,' placing it in a new genus Bathyfaus. Recent expeditions and fresh investigations have tended 1 Speaking of this animal, the Amoeba porrecta, Max Schultze says : ' It sends out from its colourless body, on all sides, numerous fibrous processes, short and broad on their first extrusion, but which gradually elongate until they exceed the diameter of the body eight or ten times, and taper to such fine extremities that a magnifying power of 400 dia- meters is needed to distinguish them. The figure ,and extension of the body change every moment, according to the side in which the ramifica- tions are extended. If two or more of the filiform processes touch, a coalescence takes place, and broader plates or net -like interlacements are produced, which, in the continual changes of figure, are either taken up again into the general mass, or otherwise are further increased by a fresh influx of matter, until finally the entire body is transposed to their place.' I THE BEGINNINGS OF LIFE. 123 to throw a great additional interest over this oceanic Moner, which, it is now believed, must have existed far back in geologic time, and must have played a most important part, by the accumulation of its in- organic remains, in the formation of ancient chalk strata, just as it is now being instrumental in the de- position of another chalk stratum in the bottom of our great Atlantic Ocean 1 . Captain Dayman was much 1 Referring to this subject in an interesting lecture ' On a Piece of Chalk' (' Macmillan's Mag.' Sep. 1868, p. 399), Prof. Huxley says: < The result of all these operations is that we know the contours and nature of the surface-soil covered by the North Atlantic for a distance of 1,700 miles from east to west, as well as we know that of any part of the dry land. ... It is a prodigious plain one of the widest and most even plains in the world. If the sea were drained off, you might drive a waggon all the way from Valentia, on the west coast of Ireland, to Trinity Bay in Newfoundland. . . . From Valentia the road would lie down hill for about 200 miles to the point at which the bottom is now covered by 1,700 fathoms of sea water. Then would come the central plain more than a thousand miles wide, the inequalities of the surface of which would be hardly perceptible, though the depth of water upon it now varies from 10,000 to 15,000 feet; and there are places in which Mont Blanc might be sunk without showing its peak above water. Beyond this, the ascent on the American side commences, and gradually leads, for about 300 miles, to the Newfoundland shore. . . . Almost the whole of the bottom of this central plain (which extends for many hundred miles in a north and south direction) is covered by a fine mud, which, when brought to the surface, dries into a greyish-white, friable substance. You can write with this on a black board, if you are so inclined, and to the eye it is quite like very soft, greyish chalk. Examined chemically, it proves to be composed almost wholly of carbonate of lime ; and if you make a section of it in the same way as that of the piece of chalk was made, and view it with the microscope, it presents innume- rable GlobigerincB, embedded in a granular matrix. . . . Thus this deep sea mud is substantially chalk. I say substantially, because there are 124 THE BEGINNINGS OF LIFE. struck with the sticky, viscid character of the mud from great depths, and thus speaks of it in his Report 1 : 'Between the i5th and 45th degrees of west longitude lies the deepest part of the ocean, the bottom of which is almost wholly composed of the same kind of soft mealy substance, which, for want of a better name, I have called ooze. This substance is remarkably sticky, having been found to adhere to the sounding-rod and line (as has been stated above), through its passage from the bottom to the surface, in some instances from a depth of more than 2000 fathoms.' This is the character of the mud in the warm area of the ocean, though the more recent expeditions of Dr. Carpenter and Professor Wyville Thompson have shown that the character of the bottom is totally different in the cold portion of the strait between the Faroe and the Shet- land Islands in that part over which flows the down- current from the Arctic basin. Referring to Captain Dayman's description, Professor Huxley says 2 : c This stickiness of the deep sea mud arises, J suppose, from the circumstance that, in addition to the Globlgerina of all sizes which are its chief constituents, it contains innumerable lumps of a transparent, gelatinous sub- stance. These lumps are of all sizes, from patches a good many minor differences.' For further information on this most interesting subject we must refer the reader to the Lecture itself. 1 ' Deep-Sea Soundings in the North' Atlantic Ocean,' 1858. 2 On some Organisms living at great Depths in the North Atlantic Ocean, 'Quarterly Journal of Microscopical Science,' October, 1868, p. 105. THE BEGINNINGS OP LIFE. 125 visible with the naked eye to excessively minute par- ticles. When one of these is submitted to microsco- pical analysis it exhibits imbedded in a transparent, colourless, and structureless matrix granules, cocoliths, and foreign particles V But those who wish to make themselves acquainted with the Protamcebtf, need not seek for them only in comparatively inaccessible regions. They are in reality common in the fine surface mud of many of our fresh- water ponds, and may easily be detected by the skilled microscopist when once he has familiarized himself with their appearance. We have lately detected, in material taken from such situations, organisms similar in kind though much more minute than the Protamceba 1 One of the most interesting subjects attaching to these lower organ- isms of the Protistic kingdom, is the enquiry as to how they are nourished whether, like plants, they live upon inorganic elements abstracted from their environment, or, like animals, upon organic substances already elaborated. Dr. Wallich has strongly maintained the former view in opposition to Dr. Carpenter's opinions that the Foraminifera are nourished after the fashion of animals. In these and in similar low oceanic organisms he has frequently expressed his belief that ' nutrition is affected by a vital act which enables the organism to extract hydrogen, oxygen, carbon, nitrogen, and lime from the surrounding medium, and to convert these ingredients into sarcode and shell material.' (' Monthly Microscopical Journal,' January i, 1869.) This elimination of inorganic elements, and their conversion into protoplasm, Dr. Wallich believes to be dependent upon ' a special vital force inherent in the protoplasmic mass itself, and diffused, in all probability, throughout its substance.' In view of this hypothesis, or of certain modifications thereof, concerning Protistic life, it is most interesting for us to learn, from the analyses of Dr. Frankland, that a large quantity of nitrogen, both free and combined, exists in the water of the Atlantic Ocean. 126 THE BEGINNINGS OF LIFE. primiti'va of Prof. Haeckel. These have presented them- selves in the form of minute irregularly-shaped, almost transparent specks of homogeneous jelly, about To( ^ 0(> " in diameter. They seldom showed even a vacuole in their interior. They underwent slow, though obvious changes in form ; and they exhibited slight to-and-fro, or somewhat jerkingly-progressive movements. Essen- tially similar organisms will, in all probability, here- after be found to be most widely distributed. They are, in almost every respect, similar to the minute jelly- specks, which we shall afterwards find making their ap-. pearance in previously homogeneous organic solutions; and they are, we believe, thoroughly primordial organ- isms, capable of originating de novo in organic solutions. Concerning this part of our subject, however, we shall have more to say hereafter. This then is the material which was spoken of by Professor Huxley 1 as c The Physical Basis of Life;' and the upholders of the Protoplasm or Sarcode theory main- tain that this substance has an essential unity of nature. So that, in spite of minute specific and isomeric dif- ferences, we have in reality to do with one and the same generic substance, whether existing as the 'contents' of animal and vegetable cells, or as naked masses of proto- plasm whether as parts of higher organisms, or as single independent beings such as we have just been de- scribing. The belief that all these various forms are but 1 ' Fortnightly Review,' 1869^ THE BEGINNINGS OF LIFE. 127 trifling alterations of a single genus of primitive organ- izable material, and that in all cases this * albuminous material is the original active substratum of all vital phenomena, may/ says Professor Haeckel, < perhaps be considered one of the greatest achievements of modern biology, and one of the richest in results/ Protoplasm then, in its most general and undifferen- tiated condition, in the form of a naked contractile mass of seemingly homogeneous jelly, is the substratum for all the life-movements of the lowest living things, even in their adult condition. A structureless mass of jelly suffices for the display of all the vital phe- nomena of the lowest organisms. Here, without the aid of organs of any kind, are carried on the vital phenomena of c growth' and c reproduction ;' here do we see the first germs of that organic irritability and contractility which attain their highest development in the conscious sensibility and power of -movement pos- sessed by those living things which stand at the head rather than at the foot of organic nature. Here does that which has what we call Life approximate most closely to that which has no Life : and who will venture to draw a rigid line which is to separate these two categories from one another ? As we have said before, the theory of evolution knows nothing of c absolute commencements;' rather, as Mr. Herbert Spencer puts it, ' every kind of being is conceived as a product of modifications wrought by insensible gradations on a pre-existing kind of being.' We must not, therefore. 128 THE BEGINNINGS OF LIFE. look for an absolute barrier between the Living and the not-living. We know nothing of an absolute com- mencement of Life ; we may know some of the lowest living things, as mere specks of almost inconceivable smallness, barely perceptible even by our highest micro- scopic powers but these are even then living organic units. We cannot, however, penetrate further who can describe the primordial collocations ? However much we may wish it, we cannot be present at the genesis of Life the veil is still there. The gradual transition from the not-living to the Living is still hidden from our view, and so, perhaps, it may ever remain. CHAPTER IV. RELATIONS OF ANIMAL, VEGETABLE, AND MINERAL KINGDOMS. THEORIES OF ORGANIZATION. The two higher Organic Kingdoms. Relations of Plants and Animals to one another, and to Air, Earth, and Water. Plants produce and Animals consume organic matter. Plants derive Carbon from the air. Illustrations from past succession of Life on our globe. Nature's Cycle. Plants continually producing Living Matter from inorganic materials. Theories of Organization. Cells. Doctrines of Schleiden and Schwann. Views of Goodsir. Virchow's Cellular doctrines. Modifications of views concerning the Cell and its powers. These necessitated by our knowledge of the Protista. Cells and Plastides. Dr. Pile's views concerning Germinal matter and ' Formed material.' Prof. Huxley's opposition to Cellular Theories. Dr. Hughes Bennett's ' Molecular Theory of Organization.' Doctrine now maintained by very many Physiologists. This in harmony with Evolution Hypo- thesis. Reason why Cells are so common as morphological units. Do they arise de novo in blastemata ? EAVING now for a time the consideration of the nature of the lowest known forms of Life, and all speculations as to the mode of evolution of those combinations of matter and motion out of which, by the most insensible gradations, they have gradually arisen, it will be desirable to turn our attention to the mutual relation of Plants and Animals to one another, K 130 THE BEGINNINGS OF LIFE. and to those great storehouses of inorganic elements earth, air, and water. Whatever be the nature of the functions of the lowest living things, and their relations with the environment, or aqueous medium in which they alone exist, we find, on coming to those more definite organisms which can, without room for doubt, be ranged under either the Animal or the Vegetable Kingdom, that the members of each great class have functions definitely related to one another and to the world of unorganized matter. Bearing in mind that the fundamental constituents of living things are carbon, nitrogen, hydrogen, and oxygen, we must also remember that the degree in which other constituents (such as sulphur and phosphorus with various saline materials) enter into the composition of organic matter, is altogether trifling when compared with the immense bulk of living tissue that is almost solely built up of these four elements in their diverse modes of combination. We shall then be the better able to appreciate the doctrine so eloquently expounded by the eminent French chemist, M. Dumas, in a work by himself and M. Bous- singault, on c The Chemical and Physiological Balance of Organic Nature.' He calls attention again and again, in the most forcible language, to the all-important com- plemental relation existing between the functions of plants and animals. Plants in their natural and healthy state decompose carbonic acid incessantly, fixing its carbon and setting free its oxygen : similarly they de- THE BEGINNINGS OF LIFE. 131 compose water, seizing upon its hydrogen and releasing its oxygen ; whilst, lastly, they abstract nitrogen either directly from the atmosphere, or indirectly from the nitrate of ammonia which, under particular conditions, has been formed therein. Plants, therefore, are mar- vellous apparatuses of reduction, working with the aid of the heat and light derived from the Sun. But this is not all. The carbonic acid, the water, and the nitrate of ammonia are decompounded, because the carbon, the hydrogen, and the nitrogen entering into their compo- sition, unite with oxygen to produce the various organic substances entering into the fabric of plants. Reduc- tion takes place, but only that combinations of a higher order may arise. Animals, on the contrary, are true apparatuses of combustion: in their bodies carbon- aceous matters are burnt incessantly during the per- formance of animal functions, and are returned to the atmosphere in the shape of carbonic acid; hydro- gen burnt incessantly is returned as water; whilst nitrogen is ceaselessly exhaled in the breath and thrown off in the different excretions 1 . c From the animal 1 This continual process of combustion is dependent upon the con- joint and reciprocal action of the respiratory and nutritive functions. Through the process of respiration the animal is supplied with an all- important element, needed for the production of such changes. Mr. Spencer says: 'The inorganic substance, however, on which mainly depend these metamorphoses in organic matter, is not swallowed along with the solid and liquid food, but is absorbed from the surrounding medium air or water, as the case may be. Whether the oxygen taken in, either, as by the lowest animals, through the general surface, or, as by the higher animals, through respiratory organs, is the immediate cause K 2 132 THE BEGINNINGS OF LIFE. kingdom, therefore, as a whole,' M. Dumas says, c car- bonic acid, watery vapour, and azote or oxide of ammo- nium are continually escaping simple substances and few in number, the formation of which is intimately connected with the history of the atmosphere itself:' substances, too, which plants are continually needing, and are as continually abstracting from the air. M. Dumas also says : c It is in plants, consequently, that the true laboratory of organic nature resides ; carbon, hydrogen, ammonium, and water are the elements they work upon ; and woody fibre, starch, gums, and sugars, on the one hand, fibrine, albumen, caseum, and gluten, on the other, are the products that present themselves as fundamental in either organic kingdom of nature products, however, which are formed in plants^ and in of those molecular changes that are ever going on throughout the living tissues ; or whether the oxygen, playing the part of scavenger, merely aids these changes by carrying away the products of decomposition otherwise caused ; it remains equally true that these changes are main- tained by its instrumentality. Whether the oxygen absorbed and dif- fused through the system effects a direct oxidation of the organic colloid which it permeates ; or whether it first leads to the formation of simpler and more oxidized compounds, that are afterwards further oxidized and reduced to still simpler forms; matters not in so far as the general result is concerned. In any case it holds good, that the substances of which the animal body is built up enter it in a but slightly oxidized and highly unstable state ; while the great mass of them leave it in a fully oxidized and stable state. It follows, therefore, that whatever the special changes gone through, the general process is a falling from a state of unstable equilibrium, to a state of stable chemical equilibrium. Whether this process be direct or indirect, the total molecular re- arrangement and the total motion given out in effecting it must be the same.' (' Principles of Biology,' vol. i. p. 34.) THE BEGINNINGS OF LIFE. 133 plants only^ and merely transferred by digestion to the bodies of etwmals? Thus we find that the vegetable world is the great originator and source of that pabulum which is necessary for the existence of animals. Plants are the active agents ever ministering to the wants of animals. They, in fashioning their own structures, are continually giving birth to organic substances which are to consti- tute the materials necessary for the maintenance of animal life. Animals, as a rule, are powerless for the creation of organic matter 1 j they can assimilate and modify the organic substances which have been built up for them in the tissues of plants ; but they cannot abstract from earth, air, and water the elementary con- stituents of organic matter, and force them to enter into such and such combinations. They use the materials which have been elaborated for them by plants, since they all feed either directly upon members of the vegetable kingdom, or else indirectly by living upon animals which have been so nourished. Plants, then, are the great factors of organic matter the vegetable 1 ' Animals assimilate or absorb the organic substances which plants have formed. They alter them by degrees ; they destroy or decom- pound them. New organic substances may arise in their tissues, in their vessels ; but these are always substances of greater simplicity, more akin to the elementary state than those they had received. They decompose, then, by degrees the organic matters created by plants. They bring them back by degrees towards the state of carbonic acid, water, azote, and ammonia, a state which admits of their ready resto- ration to the air.' Dumas, loc. cit. p. 48. 134 THE BEGINNINGS OF LIFE. kingdom is nature's laboratory, within whose sacred precincts dead brute matter is coerced into more elevated and complex modes of being, and is made to display those more subtle characteristics which we find in living tissues. Using only the great forces of nature availing themselves only of the subtle motions ema- nating from the Sun under the names of heat, light, and actinism plants compel carbonic acid to yield up its carbon, water its hydrogen, and nitrate of ammonia its nitrogen; and, at the same time, these separated elements, with some of the retained oxygen x , are still further forced by an accumulation of these mysterious impacts to enter into combinations of a higher order. M. Dumas, speaking of the sources whence are de- rived the ammonia and the nitric acid used as food by plants, says : c They are, in fact, produced upon the grand scale by the action of those magnificent electric sparks which dart from the storm-cloud, and furrowing vast fields of air, engender in their course the nitrate of ammonia, which analysis discovers in the thunder shower. . . . As it is from the mouths of volcanoes, then, whose convulsions so often make the crust of our globe to tremble, that the principal food of plants, car- bonic acid, is incessantly poured out ; so is it from the 1 Dumas says (' Lee. de Philosophic Chimique,' p. 100, Paris, 1837) : ' These are the four bodies, in fact, which, becoming animated at the fire of the sun, the true torch of Prometheus, approve themselves upon the earth, the eternal agents of organization, of sensation, of motion, and of thought.' THE BEGINNINGS OF LIFE. 135 atmosphere on fire with lightnings, from the bosom of the tempest, that the second and scarcely less indis- pensable aliment of plants, nitrate of ammonia, is showered down for their behoof.' Thus the air is the great storehouse for the pabulum of plants, so that, look- ing at the subject, as M. Dumas says, c from the loftiest point of view, and in connection with the physics of the globe, it would be imperative on us to say that, in so far as their truly organic elements are concerned, plants and animals are the offspring of the air' It might be thought that plants derive the principal part of the ingredients with which they build up their own structures from the soil; but the experiments of M. Boussingault have long since disproved this formerly favoured assumption. He found that peas sown in pure sand, moistened with distilled water, and fed by the air alone, nevertheless found in this air all the car- bon necessary for their development, flowering, and fructification. Carbon is the most fundamental ingre- dient of the vegetable kingdom; all plants fix this substance, and all obtain it from carbonic acid either abstracting it directly from the air by their leaves, or obtaining it through their rootlets. In the latter case they may obtain it from rains which have fallen to the earth impregnated with the carbonic acid of the atmo- sphere, or else they procure it from that which is liberated by the gradual decomposition of organic par- ticles in the soil. But that the air is the great storehouse whence, either mediately or immediately, plants procure 136 THE BEGINNINGS OF LIFE. their carbon, is rendered more and more obvious to us by the consideration of such facts as those to which Schleiden refers when he says 1 : c From forests main- tained in good condition we annually obtain about 4000 Ibs. of dry wood per acre, which contains about 1000 Ibs. of carbon. But we do not manure the soil of the forests, and its supply of humus, far from being exhausted, increases considerably from year to year, owing to the breakage by wind and the fall of the leaf. The haymaker of Switzerland and the Tyrol mows his definite amount of grass every year on the Alps, inacces- sible to cattle, and gives not back the smallest quantity of organic substance to the soil. Whence comes this hay if not from the atmosphere ? The plant requires carbon and nitrogen, and in the woods and on the wild Alps there is no possibility of its acquiring these matters save from the ammonia and carbonic acid of the atmosphere. 3 How important such facts as these are in throwing light upon the past history of our globe, when we attempt to study it with the aid of those relics, preserved as fossil plants and animals, and dis- tributed through the various successive strata of its crust, the palaeontologists are best entitled to inform us. M. Ad. Brongniart, one of the most able and eloquent of these, even so long ago as the year 1838 announced, before the Academy of Sciences, the fol- 1 ' Biography of a Plant.' THE BEGINNINGS OF LIFE. 137 lowing broad views concerning the succession of Life on the earth 1 : c We know, in fact, that in the strata of older date than, or of the same epoch as, the coal formations, there are no remains of any terrestrial animal, whilst at this epoch vegetation had already made great progress, and was composed of plants as remarkable for their forms as for their gigantic stature. At a later period ter- restrial vegetation loses in a great measure the signal vigour which it formerly possessed, and cold-blooded vertebrate animals become extremely numerous : this is what is observed during the third period. c Subsequently, plants become more varied, more per- fect , but the analogues of those that existed originally are reduced to a vastly smaller stature: this is the epoch of the appearance of the most perfect animals, of animals breathing air, of mammalia, and birds. c ls there no means of discovering some cause adequate to explain in a natural way this vast development, this vigorous growth of plants breathing air, even from the most remote epochs in the formation of the globe? And, on the other hand, of the appearance of warm- blooded animals, that is to say, of animals whose aerial respiration is most active in the last periods of its formation only ? May not this difference in the epoch of the appearance of these two classes of beings depend on the difference in their mode of respiration, and 1 Quoted in Dumas and Boussingault's ' Chemical and Physiological Balance of Organic Nature.' 138 THE BEGINNINGS OF LIFE. of the circumstances in the state of the atmosphere calculated to favour the development of one and to oppose that of the other ? c Under what form at the epoch of the creation of organized beings did the whole of the carbon exist which these beings subsequently absorbed, and which is now buried with their spoils in the bosom of the earth, or which is still met with distributed among the infinite multitude of organized beings that actually cover the face of our globe ? c It is obvious that animals derive carbon neither from the atmosphere nor the soil, but exclusively from their food. c We cannot conceive how plants could have assimi- lated this carbon had it been in the solid state j and, moreover, in the formations older than those that include the first remains of vegetables, we scarcely encounter any traces of carbon. c This carbon, then, which the vegetables of the primitive world, and those of the subsequent and present world, absorbed, must necessarily have existed in a shape proper to furnish them with nutriment ; and we only know of two humus or vegetable mould, which, resulting itself from the decomposition of other vegetables, would lead us into a vicious circle, and carbonic acid, which, decomposed by the leafage of vegetables under the influence of solar light, deposits its carbon, and so serves for their growth. c It appears to me impossible, therefore, to suppose THE BEGINNINGS OF LIFE. 139 that vegetables can have derived from any other source than the atmosphere, and in the state of carbonic acid, the carbon which is found in all existing species of plants and animals., as well as that which, after having served the vast primeval forests for sustenance, has been deposited, under the form of coal, lignite, and bitumen, in the different sedimentary strata of the earth. If we suppose, then, that the whole of this carbon was diffused through the atmosphere in the shape of carbonic acid prior to the creation of organ- ized beings, we shall see that the atmosphere, instead of containing less than the one-thousandth part of its bulk of carbonic acid as at present, must have con- tained a quantity which it is not easy to estimate exactly, but which was perhaps in the proportion of 3, 4, 5, 6, and even 8 per cent/ But the experiments of M. Saussure have shown that such a super-abundance of carbonic acid in the at- mosphere, far from being detrimental, is positively favourable to the life of plants when they are at the same time exposed to the influence of the solar light and heat. So that, as M. Brongniart says, c This highly probable difference in the constitution of the atmosphere may, therefore, be regarded as one of the causes influencing most powerfully the more active and very remarkable vegetation of the first organic period of our globe 1 . 1 ' But this same circumstance must, on the contrary, have interfered materially with the decomposition of the remains of dead vegetables 1 40 THE BEGINNINGS OF LIFE. c On the other hand, this difference in the com- position of the atmosphere, so favourable to the de- velopment., growth, and preservation of vegetable matter, must have proved a bar to the existence of animals, particularly of warm-blooded animals, whose respiration, as it is more active, also requires a purer air : during this first period, consequently, not a single animal breathing air appears to have existed. c During this period the atmosphere must have been purged of some portion of the excess of carbonic acid which it contained, by the vegetables which then existed ; these assimilated it first, and subsequently buried it in the state of coal in the bowels of the earth. It is after this first period, in the course of our second and third periods, that this immense variety of monstrous reptiles makes its appearance, animals which, by the nature of their respiration, are capable of living in an atmosphere of much less purity than that which warm-blooded animals require, and were the heralds and precursors of these. c Vegetables continued incessantly to abstract a portion of the carbon of the air, and thus rendered and their transformation into soil; for this kind of decomposition is owing essentially to the abstraction of a portion of the carbon of the wood by the oxygen of the air : and if the atmosphere contained less oxygen and more carbonic acid, the decomposition in question must have been without doubt both more difficult and slower. Hence the accumulation of vegetable debris in extensive beds, even in circumstances and from vegetables which, in the actual state of the atmosphere, would give rise to no such layers of combustible material. 1 THE BEGINNINGS OF LIFE. 141 it every day more pure; but it was not till the ap- pearance of a vegetation altogether new, abounding in mighty trees, the source and origin of numerous deposits of lignite, a vegetation which seems to have covered the surface of the earth with vast forests, that a great number of mammiferous animals, analogous in all the essential features of their organization to those that still exist in the world, appeared for the first time upon its surface. c Would it not be fair to suppose from this, that our atmosphere had now arrived at that degree of purity which could alone comport with the active respiration of warm-blooded animals, and prove alike favourable to the development of plants and animals, whilst the simultaneous existence of these two orders of beings, and the inverse influence of their respiratory actions, conduce to maintain our atmosphere in the state of stability which is one of the remarkable characters of the present period ?' Such, then, is the mighty round of things, such are the interchanges ever taking place on the surface of our globe. The inorganic is continually being fashioned into the organic, and this after passing through successive changes, and after having displayed the manifestations of Life, is ever passing again into the inorganic, ever again giving up its fashioning forces. c The crude and formless mass of the air gradually organized in veget- ables, passes without change into animals, and be- comes the instrument of sensation and thought ; then 142 THE BEGINNINGS OF LIFE. vanquished by this effort, and, as it were, broken, it returns as crude matter to the source whence it had come/ c Thus,' Dumas also says, c is the mysterious circle of organic life upon the surface of the globe completed and maintained! The air contains or en- genders the oxidized substances required carbonic acid, water, nitric acid, and ammonia. Vegetables, true reducing apparatus, seize upon the radicals of these, carbon, hydrogen, azote, ammonium; and with them they fashion all the variety of organic or organizable matters which they supply to animals. Animals, again, true apparatuses of combustion, reproduce from them carbonic acid, water, oxide of ammonium, and azotic or nitric acid, which return to the air to reproduce the same phenomena to the end of time.' Thus we see that throughout vast epochs, and even in the present day, the Vegetable Kingdom has been, and now constitutes, the great laboratory in which the combination of dead inorganic or mineral materials into living matter is continually taking place. We have also seen that animals have no such direct power of elevating matter taken immediately from its inorganic sources, that they, on the contrary, avail themselves of the previously constructive energies of plants, and use for the building up of their own tissues complex sub- stances which have been obtained, more or less directly, from the members of the vegetable kingdom. We have next to enquire briefly into what has been called the c Theory of Organization/ in order to learn how far THE BEGINNINGS OF LIFE. 143 within the tissues of plants and animals there is at present, and has been taking place, a corresponding evolution of living forms^ or morphological units. This enquiry will involve a consideration of the present aspect of the 'Cellular theory' of organization, and a sketch of the principal modifications which, of late years, that doctrine has undergone. Facts are still multiplying day by day which tend to show that the elements of the tissues in man and in the higher animals are possessed of an inherent power and activity of their own of a separate indi- viduality in fact, though one which is subordinate to the higher and more complex individuality of the organism to which they belong, and as parts of which they have been evolved. Tissue elements, such as epithelial cells, are to a certain extent like distinct organisms. They have a definite Life of their own longer or shorter according to the situation in which they occur, and which is therefore very vari- ously related to that of the whole organism. Their individuality of character or function is, moreover, further shown by the power which they possess of selecting their own peculiar nutritive elements out of a complex fluid, or nutritive blastema the blood common to all parts of the organism. But, granting all this, the question then comes for consideration as to whether we are to look upon c Cells' as the invariable and ultimate morphological units whether they alone can exhibit those subordinate vital activities upon 144 THE BEGINNINGS OF LIFE. which the vital manifestations of the organism as a whole depend. On this subject much difference of opinion exists. Though we cannot go into detail, we will briefly consider the doctrines which have been principally advocated. An enormous impulse was given to such enquiries by the publication, in the year 1839, of the researches of Schleiden and Schwann 1 , who endeavoured to prove that all the tissues of both plants and animals were entirely built up of morphological units called c cells.' They believed that cells were continually being produced de novo in the bodies of plants and animals. Speaking on this subject Schwann said 2 : c The following admits of universal application to the formation of cells; there is in the first instance a structureless substance present, which is sometimes quite fluid, at others more or less gelatinous. This substance possesses within itself, in a greater or less measure, according to its chemical qualities and the degree of its vitality, a capacity to occasion the production of cells. When this takes place the nucleus usually appears to be formed first, and then the cell around it. The formation of cells bears the same relation to organic nature that crystallisation does to in- organic. The cell when once formed continues to grow by its own individual powers, but is at the same time directed by the influence of the entire organism, in such 1 ' Microsc. Researches into the Accordance in the Structure and Growth of Animals and Plants.' Translation (Sydenham Society), 1847. 2 Loc. cit. p. 39. THE BEGINNINGS OF LIFE. 145 manner, as the design of the whole requires. This is the fundamental phenomenon of all animal and vegetable vegetation. It is alike equally consistent 'with those instances in which young cells are formed within parent cells^ as 'with FIG. 4. Animal Cells. A. Flattened Epithelium cells from the inside of the mouth. ( x 260.) B. Ciliated Epithelium from the human Trachea ; magnified 350 diame- ters, a. Innermost part of the elastic longitudinal fibres, b. Ho- mogeneous innermost layer of the mucous membrane, c. Deepest round cells, d. Middle elongated cells, e. Much larger super- ficial cells, bearing cilia, and containing nucleolated nuclei. (K61- liker.) those in "which the formation goes on outside of them. The generation of the cells takes place in a fluid or in a structureless substance in both cases x . We will name 1 There are most important differences between these two modes of cell-formation dependent upon the nature of the material in the midst of which the new units arise. This will be pointed out further on. L 146 THE BEGINNINGS OF LIFE. this substance in which the cells are formed, cell- germinating material (Zellenkeimstoff), or cytoblas- tema. It may be figuratively, but only figuratively, compared to the mother-lye from which crystals are deposited.' The cells thus formed might remain isolated, or, by the subsequent development and coalescence of their walls in different ways, they might tend to produce the various textures of the plant or animal. All the tissues being thus either made up of cells variously aggregated or derived by a metamorphic process from cells, they maintained that ' the cause of nutrition and growth resides, not in the organism as a whole, but in the separate elementary parts the cells.' Schwann believed that the c same process of development and transformation of cells within a structureless substance is repeated in the formation of all the organs of an organism, as well as in the formation of new organ- isms;' and he thought that the fundamental phenome- non attending the exertion of productive power in organic nature was always of this kind. Shortly afterwards Professor Goodsir 1 advanced the doctrine that it was not so much the cells as the nuclei of the textures which are the potential elementary parts of the organism, and which therefore may be called c centres of nutrition.' In a communication on this subject he said : c The centre of nutrition with which we are most familiar is that from which the whole 1 Anatomical and Pathological Observations,' 1845. THE BEGINNINGS OF LIFE. 1471 organism derives its origin the germinal spot of the ovum. From this all the other centres are derived, either mediately or immediately, and in directions, numbers, and arrangements, which induce the configu- ration and structure of the being. ... As the entire organism is formed at first, not by simultaneous formation of its parts, but by the successive develop- ment of these from one centre, so the various parts arise each from its own centre, this being the original source of all the centres with which the part is ulti- mately supplied. . . . From this it follows, not only that the entire organism, as has been stated by the authors of the cellular theory, consists of simple or developed cells, each having a peculiar independent vitality, but that there is, in addition, a division of the whole into departments, each containing a certain number of simple or developed cells, all of which hold certain relations to one central or capital cell, around which they are grouped 1 . It would appear that from this central cell all the other cells of its department derive their origin/ And then he adds : c Centres of nutrition are of two kinds those which are peculiar to the textures, and those which belong to the organs. The nutritive centres of the textures are in general permanent. Those of the organs are in most instances peculiar to their embryonic stage, and either disappear ultimately or break up into the various centres of the 1 This doctrine of ' departments,' doubtless, suggested to Virchow his modification of a similar conception, concerning ' cell territories.' L 2 148 THE BEGINNINGS OF LIFE. textures of which the organs are composed. . . . A nutritive centre, anatomically considered, is merely a cell, the nucleus of which is the permanent source of successive broods of young cells.' But later still, Virchow announced l views which have had an immense influence on pathological doc- trines throughout all the schools of medicine, and wherever biological studies have been cultivated. He, too, maintains that c the cell is really the ultimate morphological unit in which there is any manifesta- tion of life, and that we must not transfer the seat of real action to any point beyond the cell 2 .' But then he denies altogether the origin of cells de nopa "MevoiTiov d\KifJ.ov vlov Mufat Ka58vffai Kara x a ^ KOT ^' I Eu\as fjyfivcavrat, dfiteiffauffi *E/f 8' alwv irctparai Kara 8e Which is thus rendered in the late Lord Derby's translation : ' Yet fear I for Menoetius' noble son, Lest in his spear-inflicted wounds the flies May gender worms, and desecrate the dead, And, life extinct, corruption reach his flesh.' S 258 THE BEGINNINGS OF LIFE. animal in which they were found. And, similarly, he believed that the grubs which are to be met with in the galls of plants, are produced by a modification of the living substance of the plant these galls being, in fact, as he thought, organs destined to produce such animals '. In 1745, Needham, who was shortly after- wards elected a Fellow of the Royal Society of Lon- don, came forward with much additional evidence in favour of the doctrine of c spontaneous generation/ and affirmed that, if the mere putrefaction of meat could not of itself engender insects, as Redi had shewn, it could at least give origin to myriads of microscopic animalcules. Four years after the publication of Need- ham's researches, the great naturalist Buffon expounded his views 2 concerning 'organic molecules,' and the uni- versal origination of the lowest forms of animal life, by a process answering to what was termed c spon- taneous generation/ He said : c There are, perhaps, 1 'Esperienze intorno alia Generazione degl' Insetti,' p. 129. Redi was therefore a partial believer in the doctrine which we now name Heferogenesis. According to this doctrine, as taught by Burdach and others, strange living things might be generated from the matter of pre-existing living beings, both during their life and after their death. In the opinion of Redi, however, such a process could only take place whilst the parent organism was living (Loc. cit. p. 14). It will after- wards be more fully seen that this is quite an unimportant limitation, because it is one of a purely arbitrary nature, based upon the imperfect knowledge of the time. We now know that the constituent elemental parts of one of the higher organisms may continue to live long after the organism as a whole is dead. 2 These will be referred to more fully in a subsequent chapter. THE BEGINNINGS OF LIFE. 259 as many living things, both animal and vegetable, which are produced by the fortuitous aggregation of "mole- cules organiques," as there are others which reproduce themselves by a constant succession of generations/ But it was the experiments of Needham, more espe- cially, that aroused one who was for a long time the most celebrated opponent of these doctrines. The re- nowned Abbe Spallanzani soon took up the question, and entered into a controversy with Needham on the subject. He maintained that the air of our atmosphere bears with it everywhere the germs of infusorial ani- malcules and of other organic forms, and that Needham had not taken sufficient account of this fact in his experiments. In this view he was supported by the fantastic assumptions of Bonnet, and their doctrine since known by the name of ' Panspermism' has re- ceived the most powerful support from Pasteur and others in our own times. The questions in dispute could not be settled by these two champions, and suc- cessive advocates were continually springing up in favour of one or other of the adverse doctrines till the commencement of our own century. Two of the most famous of them, Gleichen and Otho F. Muller, were dissentients from the doctrines of Bonnet and Spallanzani. A little later Treviranus made known an important fact in favour of the doctrine of heterogeny, to the effect that the species of animalcules found in the infusions varied with, and seemed to depend upon, minute differences in the nature of the infusions them- s 2 260 THE BEGINNINGS OF LIFE. selves. In 1809 appeared the ' Philosophic Zoologique' of Lamarck, in which he expressed himself strongly in favour of the spontaneous origination of Life declaring that matter was continually changing, not only in regard to its states of combination, but also changing in its nature that it was now passing from the living state into a lifeless one, and now again assuming the forms and properties of living matter under the combined and mystic influence of heat, light, electricity, and moisture. c These transitions/ he said, c from life to death and from death to life, evidently form part of an immense circle of all kinds of changes to which, in the course of time, all physical substances are submitted.' But such a mode of origin was only possible, as he thought, for the lowest kinds of living things. This is expressed in the following passage, which he also prints in italics : c La nature a Paide de la chaleur, de la lumiere^ de F electricite^ et de Fkumidite^ forme des generations spon- tanees ou directes a Pextremite de cha^ue regne des corps vivants, ou se trouvent les plus simples de ces corps. 3 Soon afterwards, two philosophers, Cabanis and Oken, also declared their belief in the possibility of a new evolu- tion of life out of dead inanimate matter. According to Oken, c the animal body is only an edifice of mo- nads, 3 and c putrefaction is nothing more than the dis- aggregation of the monads, and a return to the primi- tive condition of the animal kingdom.' Then fol- lowed other distinguished naturalists, amongst whom we may mention Bory St. Vincent, Bremser, Tiedemann, THE BEGINNINGS OF LIFE. 2:6' I J. Miiller, Dujardin, and Burdach, who were all more or less in favour of the doctrines of heterogeny. These views received their fullest and most complete expo- sition, however, from the last whom we have men- tioned. In his well-known work, Burdach gave a some- what detailed account of his views on that primordial mode of generation to which he first attached the name c generatio heterogenia.' But like those of his pre- decessors and fellow-countrymen, Bremser and Tie- demann, his views were of a retrograde description, when compared with those of Lamarck. He no longer limited the possibility of such a mode of origin to the lowest members of the animal and the vegetable king- doms, but also contended that certain worms, insects, Crustacea, and even fish might in this way appear upon the scene without grdinary parentage. After him, however, came Pineau in 1845, who de- clared that he had actually watched, step by step, the heterogenetic origin and development of two ciliated infusoria Monas lens and a Vortnella and also of a microscopic fungus Penicillium glaucum. This was the first announcement of a kind of evidence altogether new based upon actual observation rather than upon experimental inference. Advocates of the opposite or panspermic doctrine, however, were abundant enough also during the first half of the present century : amongst the most distin- guished of these must figure the names of P. Gervais, Schwann, Schultze, and Ehrenberg. The latter, in his 262 THE BEGINNINGS OF LIFE. remarkable c Memoire sur le developpement et la duree de la vie des infusoires,' endeavoured to establish the fact that the generation of infusoria takes place normally by means of eggs, and that their multiplication by this process, in combination with that by fission, was suffi- cient to account for their numbers in organic infusions. Schultze and Schwann, however, sought to undermine the position of the heterogenists by adducing experi- mental proofs in support of the panspermic doctrine. Schultze alleged that no organisms of any kind were produced in a fermentable solution which had been raised to a temperature of 212 F., provided the air which was allowed access to this fluid had been pre- viously made to traverse concentrated sulphuric acid, so as to free it from all possible germs ; and Schwann stated that the experiments were, with certain reser- vations *, marked by the same sterility when calcined or highly heated air only was allowed access to the vessel containing the previously boiled solution of organic matter. These assertions, which have been subsequently disproved, had an immense influence at the time against the doctrine of heterogeny. Though in the intervening years the subject was still worked at from time to time, yet almost a new epoch in the controversy may be said to have commenced 1 His results were conflicting and contradictory whilst dealing with materials which underwent the alcoholic fermentation. Sometimes organisms were to be met with in such solutions in spite of all his precautions. THE BEGINNINGS OF LIFE. 263 about twelve years ago. Since this time, and in France more especially, the truth or falsity of the doctrine of c spontaneous generation ' has formed the subject of a most vigorous discussion. Its renewal was initiated in 1858 by the communication of a paper by M. Pouchet to the Academic des Sciences of Paris, entitled c Note sur des Proto-organismes vegetaux et animaux nes spontanement dans Fair artificiel et dans le gaz oxy- gene/ The views and experiments of M. Pouchet were warmly repudiated by men so distinguished as MM. Milne-Edwards, de Quatrefages, Claude Bernard, Dumas, Payen, and Lacaze Duthiers. Nevertheless, Professor Mantegazza very shortly afterwards also com- municated to the Academy of Sciences the results of his researches upon the generation of infusoria, which he had previously laid before an Italian academy in 1852. The conclusions at which he had arrived agreed almost perfectly with those of M. Pouchet- and in the following year the latter published his treatise on c Hete'rogenie ] ,' in which much new matter was added in support of his doctrines. But it would be in vain for us now to attempt to follow out all the intricacies of the discussions which have taken place since this time 2 . Many of the most interesting points will be 1 To this treatise we must refer those also who desire a more com- plete historical sketch than we have deemed it necessary to give. 2 This has been attempted by M. Pennetier, in a work entitled ' L'Ori- gine de la Vie,' which, in addition to a sketch of the later stages of the controversy up to the year 1869, contains a very complete list of works and papers on the whole subject, arranged in chronological order. 264 THE BEGINNINGS OF LIFE, alluded to in our succeeding chapters though others will scarcely be referred to, as we wish to narrow the question in dispute down to its simplest issues. We will, now, only state that early in the following year an accomplished chemist, M. Pasteur, entered the field, and henceforth became the most prominent ob- jector to the doctrines of heterogeny. Although many others have taken part in the contest, still it was, for a long time, in the main carried on between M. Pasteur on the one hand (backed by the immense moral support of the French Academy) and by MM. Pouchet, Joly, and Musset, on the other. Most valuable experimental evidence was, however, adduced in 1862 in support of the possibility of the origin of living things from not-living matter, by Professor Jeffries Wyman of Cambridge, U. S. } and in 1 868 by Professor Cantoni of Pavia. CHAPTER VII. MODE OF ORIGIN OF PRIMORDIAL LIVING THINGS I NATURE OF PROBLEM. Changes which occur in an Organic Infusion. Evolution of Gas. Plastide-particles and Bacteria. Formation of ' Pellicle.' Mode of formation of Bacteria. Views as to their nature. Different kinds of Bacteria and allied organisms Vibriones, Leptoihrix, and Spirillum. Composition of ' proligerous pellicle.' Views of Cohn and Pouchet. Sometimes no ' pellicle' forms, only turbidity, flocculi, or deposit. Mode of origin of Torula. Views of Hallier. Micro- cocci, cryptococci, and arthrococci. Their mutual relations to one another and to Fungi. Nature and mode of origin of Sarcina. Development of Fungus ' spores.' Doubt as to mode of origin of these forms. Useless to look in Air for germs of Bacteria. Mode of appearance of these in thin films of fluid. Only two explanations possible. Origin either germless or from invisible germs. Existence of latter must not be recklessly postulated. Similar problem in case of origin of Crystals. Statical and dynamical aggregates. Solution of problem concerning Crystals. Mr. Rainey's observations. Micro- scopical evidence similar in both cases. This can neither confirm nor invalidate the supposition as to invisible germs, crystalline or living. The existence of both equally hypothetical. WHEN a fluid containing an organic substance in solution is allowed to remain in contact with air during moderately warm * weather, it soon undergoes 1 Fermentation usually ceases in an organic solution when the tem- perature falls to about 45 F. ; and it is interesting to find that the poetic imagination of Ovid had, by a kind of happy guess, led him to attach 266 THE BEGINNINGS OF LIFE. changes of a putrefactive or fermentative character. A slight evolution or liberation of gas generally takes place as the first obvious stage of the process 1 , and after a variable time (hours or days, according to the temperature, the nature of the solution, and other modifying conditions) during which the infusion has gradually become more and more turbid, a slight whitish, though semi-translucent, scum or pellicle, that soon thickens into a membrane, makes its appearance on the surface of the fluid. This constitutes the c primor- dial mucous layer' of Burdach, or the c proligerous the same importance to the influence of solar heat in the evolution of Life which modern science now allots to it. We have already quoted one passage to this effect, but here is another : ' Ergo ubi diluvio tellus lutulenta recenti Solibus aetheriis, altoque recanduit aestu, Edidit innumeras species.' 1 This may be well seen by adding to the fermentable infusion suffi- cient isinglass to ' set' the fluid slightly. The bubbles of gas liberated, are for a long time retained in the slightly gelatinous liquid, and may be seen throughout its substance. Very contradictory opinions prevail as to the order of appearance and cause of this gaseous evolution. M. Pas- teur believes that the evolution of gas takes place after the appearance and on account of the changes induced by the presence of organisms. In his opinion all fermentations are brought about by the presence and development of organisms (derived from the atmosphere) in the fer- menting fluids. His opponents, however, maintain that the organisms are results of chemical changes brought about by physical conditions in the molecularly mobile and unstable matter of an organic infusion, and that the gaseous evolution is dependent upon some of these ante- cedent, or formative, chemical changes. The gases most commonly liberated in fermentations and putrefactions are hydrogen, carbonic acid, sulphuretted hydrogen, or ammonia. THE BEGINNINGS OF LIFE. 267 pellicle ' of Pouchet. On microscopical examination of the fluid by the highest powers, as soon as it begins to grow clouded, it will be found swarming with multitudes of mere moving specks or spherical particles, inter- mixed with short staff-like bodies, known as Bacteria, which also exhibit more or less active movements. The specks, that have hitherto been called c Monads 1 } or 'microzymes 2 ,' I shall henceforth term plastide-particles. They are primordial particles of living matter, and may be seen, with our present optical powers, to vary between -^-oW" and ^ w " in diameter. An examination of the c pellicle,' moreover, shows that it is composed of a dense superficial aggregation of such bodies as may previously have been found diffused through the liquid. In addition to plastide- particles and Bacteria, however, other low organisms, of 1 Much confusion results from the classifications of the older natu- ralists, who (following O. F. Miiller) arranged under the same genus (Monas) the mere moving specks above referred to, and also certain of the most elementary and smaller of the Ciliated Infusoria of which the so-called Monas lens is about the most abundant representative. It will now be better, in order not to clash with modern usage, to follow the example already set by others, and to restrict the word ' Monad ' to the ciliated organisms which have lately been so well described by Cien- kowski and others. 2 They were called Microzyma by B^champ, but I do not adopt this designation, because it is too special. All minute living particles, whose nature cannot be distinguished by the microscope, may well be desig- nated by one generally applicable name. Minute off-castings from white blood corpuscles are quite indistinguishable microscopically from the living specks which appear in fermenting solutions, and yet it would not be reasonable to call the former ' small ferments ' (microzymae). 268 THE BEGINNINGS OF LIFE. which we shall subsequently speak, are very often found in both situations. With regard to the mode of origin and nature of Bacteria^ much difference of opinion still exists. They have been supposed by some persons to result from the coalescence and fusion of plastide-particles ; whilst the longer and more developed bodies, called Vibriones, have been thought to result from a similar union of Bacteria. This is the view of M. Dumas and of Dr. Hughes Bennett, though it is doubted by Pouchet and most other observers. It seems much more probable that both Bacteria and Vibriones are only later stages in the growth and development of certain primary plastide- particles. Dr. Bennett 1 states that he has actually seen the union above referred to taking place ; but, judging from my own experience, I should say that it is an occurrence of the most extreme rarity. During a very long series of observations I have never per- ceived such a coalescence. The most discordant opinions have always existed as to the nature of these Bacteria. Naturalists have been in doubt as to whether they should be regarded as independent living things of the lowest grade, having an individuality of their own ; or whether, rather, they should be looked upon as developmental forms of some higher organisms either animal or vegetal. There seem to be four principal views con- 1 'Pop. Science Rev.,' Jan. 1869. THE BEGINNINGS OF LIFE. 269 cerning them: (i) that they are animal organisms of the lowest grade, having an individuality of their own, as conjectured by Ehrenberg; (2) that they are, as supposed by Hallier, of the nature of spores, produced from, and destined again to develop into, some of the simplest microscopic fungi ] ; (3) that they represent, 1 This view has been advocated by Dr. Polotebnow of St. Petersburg, in a memoir presented to the Vienna Academy on June 3, 1869. He thinks that Bacterium, Vibrio, and Spirillum are all developmental stages of Penicillium glaucum. Prof. Huxley has lately (' Quart. Journal of Microsc. Science,' Oct. 1870, p. 360) expressed opinions having a similar bearing. It will be seen, however, from the words which are placed in italics, that Prof. Huxley's views on this subject are, in part, mere sur- mises, rather than positive impressions based on a complete research. He says : ' With Torula, then, we find Bacteria in great numbers in this quiescent state. Usually masses are to be seen adhering very closely or tightly to one Torula cell or another, and such masses are very difficult to separate from the cell to which they are fixed. // seems probable that the Bacteria proceed in this way from the Torula cells, as the Torula cells do from Conidia. // is probable that Bacterium is a similar thing to Torula a simplest stage in the development of a fungus. By sowing Conidia you also get Bacteria in abundance. You get the Bacteria adhering like this (fig. 6, d) to the Conidia, and they are, / believe, developed from the protoplasm of the Conidia just as Torulae are ; and we may compare these two forms to the Microgonidia and Macro- gonidia of Algae. They are all terms in the development of Penicillium.' With reference to this theory, my own observations make me certain that Bacteria may appear in solutions (thin films) where no Torula exists. And more rarely, Torula cells may be seen in myriads in infusions, not only without attached Bacteria, but even without any discoverable Bacteria in the free state. I am quite familiar with this appearance, as of budding Bacteria, in connection with Torulce and certain mycelial filaments. I look upon it, however, as the exception rather than the rule ; and even where it exists, it seems by no means clear that the appearance is not due to the mere adhesion of some of the previously free Bacteria, which, in such cases, are always to be found co-existing with the Torula or .F^s-filaments. 270 THE BEGINNINGS OF LIFE. as Cohn 1 thinks, the later free-swimming stage in the existence of certain algae, intermediate between Pal- mell' in diameter, containing seg- mented protoplasmic contents. There were also in the THE BEGINNINGS OF LIFE. 357 fluid itself a number of medium-sized, unsegmented Bacteria, whose movements were somewhat languid \ Experiment 2. A closed flask containing a filtered infusion 2 of turnip, was opened five days after it had been hermetically sealed. On the second day after the flask had been sealed, the previously clear solution began to exhibit a cloudy appearance. The next day a reticulated scum was seen on the surface of the fluid, which gradually became more manifest on the two following days. When the neck of the flask was opened, its contents were found to emit a most foetid, sickly odour. Microscopical examination revealed Bacteria, and a very large number of Vibriones mostly without joints some straight and others bent, some motionless and others exhibiting languid movements. These, mixed up with a thickly interlaced network of Leptothrix 1 This experiment was one of a series of six, in which the same hay solution was employed (see Appendix C, pp. xlii-xlvi). A flask in which the hay solution had been boiled without any addition of carbolic acid, and which had been sealed after the solution had become cool and the flask was full of ordinary air, yielded no organisms. 2 This and other infusions of a similar nature have been prepared by cutting a portion of white turnip into small thin slices, and then pour- ing warm water upon them (in a suitable vessel) up to rather above the level which they alone had reached. The infusions were then allowed to stand near a fire for three or four hours, so as to keep them at a temperature of from no-i3OF. Nothing is easier than to obtain negative results in such experiments : it is only necessary to use weak infusions, more especially if, during their preparation, they have been kept for a prolonged period at a temperature near to that of boiling water, instead of at a heat which can be supported by the finger. 358 THE BEGINNINGS OF LIFE. filaments, constituted the reticulated pellicle which was seen on the surface. The Leptothrix fibres were partly plain, and partly segmented; they presented except in respect of their length an appearance almost pre- FIG. 24. Bacteria, Vibriones, and Leptothrix filaments met with in a Turnip Infusion which had been only five days in vacuo. ( X 800.) cisely similar to the Vibriones. The long filaments seemed, in fact, to be only developed forms of the shorter rod-like bodies. Experiment 3. A closed flask containing an infusion of turnip 1 , was opened seventeen days after it had been hermetically sealed. The fluid never exhibited any distinct turbidity, and no pellicle formed on the surface ; there was, however, an irregular covering of the bottom of the flask by fine granular matter, with here and there a small patch of filamentous-looking substance. No bad odour was perceived when the flask was opened. 1 See note 2, p. 357. THE BEGINNINGS OF LIFE. 359 Unfortunately, just as I was proceeding to examine the contents microscopically, nearly all the fluid was lost, including the filamentous-looking masses. Exami- nation of a few drops of the fluid which remained showed a very large number of plastide-particles and 'Bacteria. 'Experiment 4. A closed flask containing an infusion of turnip was opened seven days after it had been hermetically sealed. The solution itself was much clouded, and its surface was covered by a thick gelatinous pellicle. On microscopical examination of the fluid it was found to contain a multitude of plastide-particles and very active Bacteria, The thick gelatinous pellicle was also made up of an aggregation of these in the usual transparent mucoid material. In very many situ- ations this uniform pellicle was undergoing a process of heterogenetic organisation^ such as will be more fully described hereafter. Experiment 5. A flask containing a very strong infu- sion of turnip was opened fifteen days after it had been hermetically sealed. The solution itself was very cloudy, and there was on its surface a thick coriaceous sort of pellicle marked by more closely-set aggregations or islets of denser growth. On microscopical examination the fluid was found to contain a multitude of plastide-particles and very active Bacteria. The Bacteria were almost more active than any I had before seen, and there were many different kinds. 360 THE BEGINNINGS OF LIFE. Some exhibited rapid serpentine movements, accom- panied by flexions of the two segments of which they are composed j whilst the movements of others were rapidly progressive in straight or curved lines. The pellicle was made up mainly of simple Leptothrix filaments (mostly without joints or evidences of seg- mentation) j and the thicker islets were found to be produced by a more luxuriant growth in these situations of densely interwoven filaments. The pellicle was found to be so tough and elastic that some of it could only be mounted as a micro- scopical specimen after it had been compressed for an hour or two, by placing a small weight on the covering glass. It would be useless to quote other experiments of the same kind, though many others have been made with similarly positive results. Those in which a hay infusion acidified by carbolic acid has been employed are most especially interesting. In no case has a properly prepared infusion of turnip failed to yield an abundance of living organisms in the course of from two to six days, although the reaction of the infusion has always been decidedly acid. A distinct pellicle, however, only forms occasionally. If a clear solution becomes turbid in a few days, with or without the formation of a thick pellicle, and if on microscopical examination the cause of the turbidity or the constituents of the pellicle have been found to be Bacteria^ Vibriones^ or Leptothrtx fila- THE BEGINNINGS OF LIFE. 361 ments, no fair critic could reasonably object to the in- ference that the organisms found were living, simply because they only exhibited languid movements more or less indistinguishable from mere molecular or Brownian movements. The property of reproduction is a fun- damental attribute of living things ; the power of performing extensive movements is not. That repro- duction has taken place must be obvious to all. How else could a clear fluid, within an hermetically-sealed vessel, become turbid owing to the presence of myriads of Bacteria ? How else could a thick pellicle form on such a solution composed of densely interlaced Bacteria., Vibricnes^ and Leptotkrix filaments? And, moreover, although in the fluid from some of the flasks the move- ments of the contained Bacteria were so languid as to be scarcely distinguishable from Brownian movements, in that of others (as, for instance, in Exps. 4 and 5) the movements were very active and unmistakeably vital. That the vessels were in no way cracked, and that the vacuum was in some cases still partially preserved, I have thoroughly satisfied myself 1 . For the rest, the 1 This is easily done by carefully heating the end of the neck of the flask (before breaking it), and then softening it with the blow-pipe flame. The insinking of the softened glass is a sure sign that the vacuum is still more or less preserved. The amount of gas liberated in different cases varies very much. In many instances it is not suffi- cient to establish an equilibrium with the external atmospheric pressure, though occasionally (even when the fluids were originally contained in vacua) the internal tension from liberated gases exceeds the external atmospheric pressure. 362 THE BEGINNINGS OF LIFE. experiments can be easily repeated by any one who is desirous of seeing such results for himself. In the next series of experiments, ammoniacal and other saline solutions have been employed. At present, we have to do with these simply as acid solutions in which living organisms have been procured. The pre- sence of living organisms in such solutions, after ebulli- tion and other proper precautions, being, in accordance with the admissions of M. Pasteur, only compatible with the de novo origination of those which first appear. I was induced to employ saline solutions for various reasons. In the first place, after having read M. Pas- teur's statements, concerning the growth and develop- ment of Fungi which had been placed in saline solutions 1 , it occurred to me that it would be a subject of much interest to determine whether any evidence could be obtained, tending to show that organisms might even be evolved de now in certain fluids of a similar character. This, in fact, seemed to be a problem of very great im- portance j for, if otherwise suitable, the employment of such saline solutions would be attended by certain advantages. It appeared likely that the saline mate- rials in solution would be far less- injured by the high temperature of 2i2F than organic substances. We should thus, also, best prepare ourselves to be brought face to face with the problem Whether the pre-existence of organic matter, which has been elabo- J Loc. cit, p. 100. THE BEGINNINGS OF LIFE. 363 rated in pre-existing organisms, is, at present, absolutely necessary for the de novo origination of living things , or whether, in fact, these may arise, more or less directly, by changes taking place in an aggregation of new-formed molecules of an organic type \ At present, however, no special precautions have been taken to ensure the purity of the chemical sub- stances employed. These may, and sometimes did undoubtedly contain organic impurities, so that the fol- lowing experiments are simply quoted as instances in which more or less acid fluids, containing at all events a very large proportion of saline ingredients, have proved productive of living organisms when treated in the way already described. SERIES b. Saline Solutions having an acid reaction. Experiment i. A closed flask containing a solution of ferric and ammonic citrate 2 in distilled water (gr. x. to |j.) was opened 29 days after it had been hermetically sealed. A small amount of powder-like sediment had gra- dually collected at the bottom of the flask, though there was no general turbidity of the fluid. Before the flask was opened it was ascertained that the vacuum was still 1 These having themselves arisen by the combination of some of the dissociated elements of the saline substances employed. 2 Some of the purest that could be obtained, from Messrs. Hopkin and Williams. 364 THE BEGINNINGS OF LIFE. partially preserved. The reaction of the fluid was found to remain slightly acid. On microscopical examination of the sediment, Bac- teria were found, having moderately active movements though they were not very numerous. There were many granular aggregations, from the midst of which were growing Leptotkrix filaments, though the organisms FIG. 25. Torula, Leptothrix, and Bacteria found in simple Solution of Ferric and Ammonic Citrate. ( x 800.) which were most abundant were Torula cells of different sizes, many of which were provided with a segment across their short diameter, whilst each half contained a nuclear particle. These Torula cells had a uniform very faint greenish hue, and homogeneous contents. They often existed in groups of 1 3-20, or more. Experiment 2. A closed flask containing a solution of ferric and ammonic citrate, together with a few minute fibres of deal wood (much less than half a grain), was opened 42 days after it had been hermetically sealed. The fluid continued clear and there was no pellicle on the surface, though, after the first two weeks a slight THE BEGINNINGS OF LIFE. 365 deposit began to collect at the bottom of the flask, which slowly increased in quantity. On opening the flask the reaction of the fluid was found to be still slightly acid; and on microscopical examination of the deposit several different kinds of organisms were discovered in and amongst the granular aggregations of which it was in great part composed. Many minute fragments of deal wood dotted ducts, 6cc. were also intermixed. Amongst the organisms were perfectly-formed Bacteria, about T -^/' in length, which were very numerous and extremely active , several long unsegmented Leptothrix filaments, ^-g^" in diameter ; many oat-shaped Torula corpuscles, about ^W in length ; three or four spherical FIG. 26. Bacteria, Leptothrix, Torulce, and other organisms found in a Solution of Ferric and Ammonic Citrate, plus some minute fragments of deal wood. ( x 800.) or ovoid fungus-spores, each having a large central nucleus, and others rather smaller, having granules within instead of a distinct nucleus; also, partly imbedded in one of the granular aggregations was a 366 THE BEGINNINGS OF LIFE, distinct cellular body, -^^' in diameter, having a sharply-defined border and finely-granular contents, in the midst of which was a large nucleus. A thick hyaline capsule seemed to shut it off from the granular matrix in which it was imbedded. And, lastly, there were a number of bodies closely resembling one of the simplest kinds of Desmids. Some of them were single ovoidal bodies, about ToW" in length, consisting of an oat-shaped mass of faintly greenish protoplasm within a larger delicately hyaline envelope. Others were com- posite, and one mass was seen composed of four much larger segments 1 . Experiment 3. A closed flask containing a solution of potash-and-ammonia alum, and of tartar emetic 2 , was opened 28 days after it had been hermetically sealed. The fluid then had a decidedly acid reaction. The solution continued clear throughout ; there was no trace of a pellicle and no deposit at the sides, though 1 Organisms closely resembling these have frequently been met with in solutions similar to the above, even when the solutions have been exposed to much higher temperatures (see vol. ii. chap. x. Exps. 8, 9, n and 12). And in a flask containing an inoculated solution of ammonic tartrate and sodic phosphate, which had been heated to I4OF, and subsequently kept for eleven weeks, bodies somewhat similar were encountered. In this case, however, they were colourless, and were associated with a number of more ordinary-looking Torula cells. The green organisms of the iron solutions bear some resemblance to the Desmids of the genus Artbrodesmus, and to the Pediastreae of the genus Scenodesmus. 2 The quantities were, unfortunately, not measured. The water used was not distilled, but was a pure drinkable water. THE BEGINNINGS OF LIFE. 367 a whitish flocculent niass was seen at the bottom of the flask after the first fortnight, which gradually increased, and at last formed a mass about " in diameter. On microscopical examination, the white mass was found to be made up of aggregations of colourless particles, varying much in size and shape, and im- bedded (f] in a distinct hyaline jelly-like material. The granules were highly refractive, altogether ir- regular in shape, and they varied in size from 3T nn/' to -g-^n/' in diameter. Though most of them were FIG. 27. Fungus met with in a solution containing Potash-and- Ammonia Alum, with Tartar Emetic, (x 600.) motionless and imbedded in the jelly, very many were seen exhibiting active and independent movements; some of these were in the form of little double spherules (j, k> s > u i w t and.y, whilst those which were executed alone by me in University College are Nos. a, b, c, d, e, f t I, m, , o, p, q, r, t, v, x* and z. THE BEGINNINGS OF LIFE. 439 c Each liquid was placed in a glass tube about three- quarters of an inch in diameter, nine inches long, and closed at one end by fusion of the glass. The open end of the tube was then drawn out so as to form a thick capillary tube, which was afterwards connected with a Sprengel's mercurial pump. The action of the pump soon produced a tolerably good vacuum, when on gently warming the liquid, the latter began to boil, its vapour expelling the last traces of air from the apparatus. After the boiling had been continued for several minutes, the tube was hermetically sealed at the capil- lary part. c The tubes were now placed in the wrought iron digester, described by me in the Philosophical Trans- actions for 1854, p. 260. It consists essentially of a cylindrical iron vessel, with a tightly-fitting cover, which can be securely screwed on to it. Through the centre of the cover passes an iron tube, which descends half way down the centre of the cylinder. This tube is closed at bottom, and contains a column of mercury about an inch long, and a thermometer plunged into the mercury shows the temperature of the liquid inside the digester. c Water being now poured into the digester until it covered the tubes, and the cover having been screwed on, heat was applied by means of a gas stove. c The temperature was allowed to rise to about 15OC, and was maintained between 146 and I53C 440 THE BEGINNINGS OF LIFE. for four hours *, and it is almost needless to say that every part of the sealed tubes and their contents was exposed to this temperature during the whole time. The glass tubes, though of moderately thick glass only, ran no risk of fracture, because the pressure inside them was approximately counterbalanced by the pressure of steam outside/ In all the subsequent experiments which I performed alone, an approximate vacuum was procured, as in my former experiments, by boiling the fluids and sealing the flasks hermetically during ebullition. The vacuum may have been somewhat less perfect in these cases than when it was procured by means of the Sprengel pump, though this circumstance does not in the least diminish the value of the experiments. The vacuum was not desired, because, by working under these con- ditions, all atmospheric c germs ' might be abstracted since in all cases the flasks were exposed to a temperature which is acknowledged to be destructive of living things whether in air or in fluids. In the experiments of Mantegazza, Wyman, and Cantoni, the portions of the closed flasks above the level of the fluids were filled with ordinary air. If, therefore, the vacuum may not have been quite so complete in some of my latter experiments as in those in which I had the benefit of Prof. Frankland's assistance, it is a matter 1 This prolonged period of exposure was subsequently only resorted to in some of the experiments. In others they were exposed for shorter periods, as will be seen from the different headings. THE BEGINNINGS OF LIFE. 441 of no importance, and does not in the least affect their value. Solutions exposed in airless and hermetically sealed flasks to 2*io-2*i$F (i32-i35C) for twenty minutes, and sub- sequently maintained at a temperature of 7o-8o F. These flasks were also exposed to direct sunlight for eight days *. 'Experiment a. A strong infusion of turnip, rendered very faintly alkaline by liquor potassae, to which a few muscular fibres of a cod-fish were added. When taken from the digester the fluid was found to have assumed a pale brownish colour. The flask was kept in a warm place, in addition to being exposed to direct sunlight. The vacuum having been ascertained to be partially preserved, the neck of the flask was broken two months after the date of its preparation. The reaction of the fluid was then decidedly acid, and the odour (differing altogether from that of mere baked turnip) was sour, though not at all foetid. The fluid was very slightly turbid, and there was a well-marked sediment consisting of reddish-brown fragments, and a light flocculent deposit. On microscopical examination, the fragments were found to be portions of altered mus- cular fibre, whilst the flocculent deposit was composed, 1 The solutions and flasks were exposed to a temperature of from no''-i35 C for one hour, if we include the twenty minutes' exposure, and also the period which elapsed till the fluid in the digester cooled down to iroC. The subsequent exposure to direct sunlight was, for several hours daily, during some very fane weather in the month of March. 442 THE BEGINNINGS OF LIFE. for the most part, of granular aggregations and bacteria. In the portions of fluid and deposit which were examined. FIG. 30. Bacteria, Torula, Fungus-mycelium, and Spores of different sizes, from a neutralized Turnip Infusion. ( X 800.) there were thousands of Bacteria of most diverse shapes and sizes, either separate or aggregated into flakes. There were also a large number of monilated chains 1 of various lengths, though mostly short , a large number of small spherical Torula cells with mere granular contents, and a smaller number of ovoid, vacuolated cells. There were, in addition, a considerable number of brownish nucleated spores, gradually increasing in size from mere specks about -^-giro" in diameter, up to bodies -2-W i n diameter ; and also a small quantity of a mycelial filament, having solid protoplasmic contents, 1 Similar to those found in other turnip infusions which have been slightly acid and not foetid. See Appendix C, Experiments xxi. and THE BEGINNINGS OF LIFE. 443 broken at intervals, and bearing bud-like projections, each of which was capped with a single spore. 'Experiment b. An infusion of common cress (Lepi- dium sativum),to which a few of the leaves and stalks of the plant were added. This was kept in the same way as the last solu- tion, and was similarly exposed to sun-light for a few days. After nine weeks, and before the neck of the flask was broken, the vacuum was found to be well preserved. The reaction of the fluid was distinctly acid, but there was no notable odour of any kind. The fluid itself was tolerably clear and free from scum, though there was a considerable quantity of a dirty-looking flocculent sediment at the bottom of the flask, amongst the debris of the cress. On microscopical examination of portions of these fragments, most of the cells in the stalks were found crowded with very actively-moving granules. In some of the leaves the chlorophyle was not much altered, whilst in others it presented various stages of decomposition being in some cells wholly replaced by a blackish-brown granular material. Large quan- tities of such matter also existed, either dispersed or aggregated, amongst the sediment; and in some of it three minute and delicate Protamceb# were seen, creep- ing with moderately-rapid, slug-like, movements and changes of form. They contained no nucleus, and presented only a few granules in their interior. Partly in the same drop, and partly in others, there were also 444 THE BEGINNINGS OF LIFE. seen more than a dozen very active Monads^ 40*00" in diameter each being provided with a long rapidly- Bacteria, Torula, Protamoebce, Monads, &c., from an infusion of Common Cress. ( X 800.) moving flagellum, with which neighbouring granules were lashed about *. There were many smaller motion- less spherules, of different sizes, whose body- substance presented a similar appearance to that of the Monads. There were also several unjointed Bacteria, presenting most rapid progressive movements, accompanied by rapid axial rotations ; many Torula- cells of different kinds, and coarser fungus spores, some of them with segmented protoplasmic contents j and lastly, some mycelial or algoid filaments, containing tolerably equal blocks of colourless protoplasm within an investing sheath. 1 A drop containing several of the Monads was placed for about five minutes on a glass slip, in a warm-water oven maintained at a tempera- ture of i4oF. All the movements of the Monads ceased from that time ; and they never again showed any signs of life. THE BEGINNINGS OF LIFE. 445 Experiment c. An infusion of beef with some mus- cular fibres, prepared at the same time, similarly ex- posed, and also opened after nine weeks, was not found to contain any living things, though there was an abundance of mere moving granules. Some of the muscular fibres had preserved their natural appearance, whilst others had lost it, and had become completely granular. Experiment d. An infusion of cod-fish muscle, simi- larly prepared and exposed, also proved quite sterile. Experiment e. A solution containing ten grains of potash and ammonia alum, three grains of tartar emetic, and half a grain of new cheese to an ounce of distilled water. The vacuum having been ascertained to be still partly preserved, this flask was opened at the end of the seventh week. The fluid was odourless, and its reaction neutral. There was a considerable quantity of dirty-looking deposit, and some oily matter on the surface, though the fluid itself was tolerably clear. The deposit was, for the most part, com- posed of dark granules, together with mucoid flakes also containing granules. Mixed with the moving gra- nules were a considerable number of Bacteria partly of the ordinary shape, and partly of the monilated variety the movements of which were tolerably ex- tensive. They travelled over small areas, and danced around one another, in a manner quite different from the mere granules with which they were intermixed. 446 THE BEGINNINGS OF LIFE. There were no traces of Torulte or Leptothrix fila- ments. Experiment f. A solution containing ten grains of ammonic tartrate and three grains of sodic phosphate, with half a grain of new cheese, to an ounce of distilled water. The vacuum having been ascertained to be well preserved, the flask was opened in the early part of the sixth week. The fluid was found to have a neutral reaction, and there was a well-marked, whitish deposit at the bottom of the vessel. On microscopical examina- tion, no Bacteria, Torul^e, or Fungi were found, but there were a great number of fibres, exactly like un- segmented Leptothrix filaments, growing from the midst of aggregations of the irregular particles of which the deposit was composed. Other filaments were seen having a close resemblance to the spiral fibres met with in somewhat similar solutions which were exposed to a lower temperature \ They were, however, in smaller masses, the spirals were less marked, and transitional states existed between them and the fibres which resembled Leptotkrix 2 . 1 See Appendix A, pp. v ix. 3 Since this was written I have seen Leptotbrix (or Spirulind] filaments, growing so as to form quite irregular, spirally-disposed masses of dif- ferent sizes. These were obtained from the surface of water, in which a few young twigs of the common elder had been immersed for five or six days. All stages were seen, also, between such spiral masses and more ordinary Bacteria and Vibrio forms. As the latter elongated they gradually became curved. Segmentations were seen, at intervals, in the internal solid protoplasm of which they were principally composed. THE BEGINNINGS OF LIFE. 447 Solutions exposed in airless and hermetically-sealed flasks to 293^ (i45C), for from five to twenty minutes ; and subsequently maintained at a temperature qf^o-So ^ 1 . 'Experiment g. A turnip infusion rendered very faintly alkaline by liquor potassse. The flask was opened after nine weeks, when the vacuum was found to be partially preserved. The fluid was still of the same light brown colour as when it was taken from the digester. Its reaction was now decidedly acid, though the odour was slightly sour and not foetid. There was a small quantity of granular scum on some parts of the surface, and a distinct brownish flocculent sediment, but the bulk of the fluid was tolerably clear. On microscopical examination of the deposit, a number of minute Torula-cells were found, both singly and in groups. They varied from the minutest specks up to bodies ^V?/' in breadth, and were mostly with- FIG. 32. Various kinds of Torula from a neutralized Infusion of Turnip. ( X 600.) out nuclei or vacuoles. Some were growing out into mycelial filaments. Other small, nucleated, spores were 448 THE BEGINNINGS OF LIFE. also met with, singly and in groups ; and in addition, a thick-walled body with granular contents, y^W' ^ n diameter. No distinct Bacteria were seen, though there were numerous acicular crystals, some solitary, and others in peculiar bundles having constrictions at in- tervals. A number of minute octohedral and prismatic crystals were also present 1 . Experiment h. A solution containing seven grains of iron and ammonic citrate (mixed with a few very minute fibres of deal wood), seven grains of ammonic tartrate, and three grains of sodic phosphate, to one ounce of distilled water. When taken from the digester this solution was found to have become fluorescent being blackish by reflected, and olive-green in colour by transmitted light. After a time, some cloud-like flakes appeared, and also an increasing quantity of sediment. After eight months, FIG. 33- Bright green Organisms resembling Pediastrece, from a Solution con- taining Iron and Ammonic Citrate and other ingredients. ( X 800.) the vacuum being still well preserved, the neck of the flask was broken and its contents examined micro- 1 Only three drops of the fluid were examined. THE BEGINNINGS OF LIFE. 449 scopically. The sediment contained a few wood fibres and ducts, and very much granular matter together with actively-moving particles, though no distinct Bacteria. There were also very many ovoid cells (single, and in groups of two to eight), about TT n/' in length, with somewhat granular and rather bright green contents in which a vacuole existed. Other somewhat similar bodies were seen in groups of four, each segment of which was surrounded by a hyaline envelope. In one group the protoplasm within the hyaline envelope was seen to have undergone segmentation. Some of this fluid was put on one side in a small corked tube, and when examined after six weeks, the cells had lost all their green colour the contents having assumed a dirty yellowish brown hue 1 . Experiment j. A solution containing fifteen grains of iron and ammonic citrate (mixed with a few minute fibres of deal wood), in one ounce of distilled water. The vacuum having been ascertained to be well preserved, the neck of the flask was broken eight months after its preparation. The fluid, which was still very faintly acid, was not fluorescent, though there had been a notable amount of sediment for some time. On microscopical examination, the latter was found to consist of dotted ducts and minute portions of woody fibre, mixed with large quantities of granular matter 1 A certain general resemblance exists between the organisms met with in this experiment, and those of Experiments j, I, and m, as well as those of Experiment 2, recorded at p. 365. 450 THE BEGINNINGS OF LIFE. (aggregated into flakes), and a great multitude of very actively-moving particles. Some of them had a figure- of-8 shape, and others were well -formed "Bacteria. There were also a few monilated chains, as well as simple unsegmented Leptothrtx filaments. The most FIG. 34. Bacteria, different kinds of Leptothrix, and green Organisms resembling Desmids, from a Solution of Iron and Ammonic Citrate. ( X 800.) notable products, however, were a great number of single and aggregated organisms, resembling certain simple Desmids and Pediastre*. Like them, also, they exhi- bited slow oscillations or partial slight rotations. Their contents were decidedly greenish, though the hue was not so bright as that of the organisms found in the last solution. Some were single, and others were in groups of four or eight \ Two drops of the solution, containing some of the sediment, were placed in a clean animalcule-cage, 1 The organisms in this solution more closely resembled those of Experiment 2 (p. 365) than those of Experiments I and m. Bacteria were contained in both, and the solutions themselves were also more similar neither of them had become fluorescent. THE BEGINNINGS OF LIFE. 451 which was kept at a temperature of 85 90 F in a developing oven. After twenty-four hours the groups and single Desmid-like bodies were still seen under- going partial rotations, and the number of "Bacteria had increased in quantity. After forty-eight hours, a group of eight cells, in addition to solitary and smaller groups, was seen distinctly oscillating ; and there were two or three elongated bodies (containing segmented blocks of protoplasm), which seemed to have resulted from the development of single organisms ; there were also several Leptothrix filaments, and a great increase had taken place in the number of Bacteria, which showed very active movements of translation. After this period the contents of the Desmid-like bodies began to fade, and they seemed gradually to die ; though the Bacteria lived and increased for several days, during which the specimen was kept under observation. Experiment k. A solution containing ten grains of ammonic sulphate, and ten minims of dilute liquor ferri perchloridi in one ounce of distilled water. A thick scum formed on the surface after about two months. The flask was opened at the expiration of the third month, the vacuum being still well preserved. On microscopical examination, no trace of living things was to be seen amongst the amorphous deposit at the bottom of the flask. The pellicle was found to present a cellular arrangement (Fig. 39). It polarized light, however, and was obviously crystalline in con- stitution. It was very heavy sinking at once in the eg 2 452 THE BEGINNINGS OF LIFE. watch-glass as soon as its upper surface was wetted. This solution contained no carbon (see Appendix A, p. x). Experiment 1. A solution containing twelve grains of iron and ammonic citrate (mixed with a few very mi- nute fibres of deal wood) in one ounce of distilled water. The flask was opened at the commencement of the seventh week from the date of preparation. It was exposed to sunlight for about eight days during the last fortnight, though previous to this the amount of sedi- ment had gradually increased. After the second or third exposure the previously dark brown fluid became fluorescent black to reflected, but olive-coloured to transmitted light. There was also a brownish deposit on one side of the tube. When the flask was opened it was found that the vacuum was almost wholly impaired, by an internal evolution of gas. On microscopical examination of a drop of the fluid (con- taining sediment), multitudes of granules, separate and aggregated into flakes, were seen. There were no dis- tinct Bacteria, though large numbers of the rounded and ovoid organisms similar to those met with in Exps. 9 and 12, were intermixed with the granules. They were partly separate, partly in groups of fours and eights. They varied considerably in size, and also in colour some being decidedly greenish, and others quite yellow and faded. In the granular aggregations, different stages in the growth of these Desmid-like bodies were to be recognized. What appeared to be short Leptothrix fila- ments issued from some of the granular masses. THE BEGINNINGS OF LIFE. 453 Experiment m. Some of the same solution as was employed in the last experiment, similarly exposed and rendered similarly fluorescent. After the exposure to sunlight, however, the tube was kept in ordinary daylight for two weeks, so that it was not opened till the commencement of the ninth week. It was then found that the vacuum was impaired as in the last experiment. On microscopical examination of the sediment the same kind of granules (separate and aggregated) were seen, and also great multitudes of the Desmid-like organisms. These existed more abundantly than in the last solution. Here also there was the same fresh appearance of some, and faded look of others, and also great variations in size the largest being TWO" i n length, whilst many were not more than length. Several groups of four were seen, in TWO" FIG. 35. Greenish, Desmid-like Organisms of different kinds, and Torulte, found in a fluorescent solution of Iron and Ammonic Citrate. ( X 800.) which the separate elements were spherical instead of ovoid. There were also many straight, or slightly 454 THE BEGINNINGS OF LIFE. curved bodies, having blocks of protoplasm within which apparently resulted from a longitudinal growth of single frustules. The groups of organisms, as well as those which were single, exhibited the same slow partial rotations, forwards and backwards, which had been observed in those produced in other solutions. Some of this solution was put into a corked tube, and when it was examined two months afterwards, all the frustules had lost their greenish colour, and were apparently quite dead. 'Experiment n. A solution containing ten grains of ammonic carbonate, and three grains of sodic phosphate in one ounce of distilled water. The flask was opened in the commencement of the twelfth week from the date of preparation, the vacuum having been previously ascertained to be well preserved. The reaction of the solution was slightly alkaline. There was no notable turbidity of the fluid, though there was a small amount of whitish deposit, which on microscopical examination was found to be mostly composed of amorphous granules. The fluid itself con- tained a small number of minute but distinct Bacteria^ and also a number of figure-of-8 shaped bodies all of which exhibited sluggish movements, They were very faint in colour, so that on this account and owing to their small size, although plentiful enough, they were somewhat difficult to recognize. A drop of the solution, on the application of the covering glass, had been immediately cemented, and when examined after THE BEGINNINGS OF LIFE. 455 twenty- four hours, both varieties of 'Bacteria had notably increased in quantity, and had become some- what larger, though their movements were not at all more active. Experiment o. An infusion of hay, which had become slightly darker by the exposure to heat, and in which a fine flocculent sediment had been thrown down. The flask was opened at the end of the seventh week, the vacuum being still well preserved. The reaction of the fluid was then found to be acid, and its odour was hay-like though somewhat altered in character. No organisms of any kind were discovered in the fluid, or amidst the minutely granular deposit. Experiment p. An infusion of turnip (not neutralized but in its natural slightly acid condition) was found to have assumed the colour of pale sherry when removed from the digester. There was also a small amount of light flocculent sediment. The flask was opened eight weeks afterwards; the vacuum having been well preserved. The reaction of the fluid was still acid, and its odour was that of baked turnip. There was a considerable quantity of granular matter at the bottom of the flask, but after careful microscopical examination, no organisms of any kind could be detected x . 1 Compare the results of this experiment with those of Nos. a and g. The very slight addition of dilute liquor potassae to the latter fluids seems to have been the immediately determining cause of their productiveness (see p. 383). Some other experiments recorded in 456 THE BEGINNINGS OF LIFE. After it had been examined, the remainder of the fluid was left in the open flask. Six weeks afterwards it was accidentally noticed,, and a bluish-green fungus was seen covering the surface of the fluid. On microscopical examination of the sediment which had collected at the bottom of the flask, multitudes of Torula cells were found, though there was a complete absence of Bacteria ] . Solutions exposed in airless and hermetically-sealed flasks to a temperature of 295 307^ (146 i53C) for four hours, and subsequently maintained at a temperature of 70 80^. Experiment q. An infusion of turnip which had been much charred by the high temperature. It had become brown in colour, and in addition there was a Appendix C, also point to the desirability of neutralizing a turnip infusion if we wish to increase the chances of finding organisms within the flasks. In Exps. a and g the odour was not that of mere baked turnip, and the solutions had become acid fermentation had in fact taken place. 1 I have also on other occasions (see Appendix C, Exp. xviii.) fre- quently found, when the fermentability of certain fluids is lowered by the influence of heat, that they yield nothing but slowly-growing Torulce, although a portion of the same fluid, unheated and standing beneath the same bell-jar, would speedily become turbid and yield myriads of Bacteria without Torula. Facts of this kind are very interesting, and serve to throw light upon the morphological differences which exist between Bacteria and Torulce. Crystals which are produced rapidly, are always smaller and less perfect in form than those of slower growth. THE BEGINNINGS OF LIFE. 457 blackish-brown deposit of charred matter, which, after it had thoroughly settled, was about equal to one-twelfth of the bulk of the fluid. The flask was opened at the end of the eighth week, when the vacuum was found to be well preserved. The odour of the fluid was for the most part that of baked turnip, and its reaction was acid. The deposit was composed of amorphous granules, and also of a mul- titude of reddish or claret-coloured spherules of various sizes, but no organisms of any kind could be dis- covered. Experiment r. An infusion of turnip rendered slightly alkaline by the addition of dilute liquor ammonias, was affected in almost precisely the same way as in the last experiment. The flask was prepared at the same time, and opened after the same interval. The deposit, in its micro- scopical characters, resembled that found in the last experiment, and there was a similar absence of all organisms 1 . Experiment s. A tube containing an unaltered infusion of turnip was opened at the end of the twelfth day. When received from Dr. Frankland, the fluid had been changed to a decided but light brown colour, and there was some quantity of a blackish-brown granular 1 Considering the results which were obtained in Exps. a and g, I think that a turnip infusion neutralized by liquor potassoe rather than liquor ammonias, is one of the most favourable combinations for producing organisms after exposure to high temperatures. 458 THE BEGINNINGS OF LIFE. sediment, though the infusion had been quite free from all deposit when placed in the digester. After this tube was suspended in a warm place, as the others had been, it remained in the same position till it was taken down to be opened. A slight scum or pellicle, which partially covered the surface, was observed on the sixth day. During the succeeding days it did not increase much in extent, though it became some- what thicker. Although very great care was taken, still the slight movement of the flask, occasioned in knocking off its top, caused the pellicle to break up and sink ] . The contents of the flask emitted a somewhat fragrant odour of baked turnip, and the reaction of the fluid was still slightly acid. On microscopical exami- nation, a great deal of mere granular debris and irregular masses of a brownish colour were found, and also a very large number of dark, and apparently homogeneous reddish-brown spherules, mostly varying in size from TSW" to 2i)ih>o" in diameter, partly single and partly in groups of various kinds. There were no distinct Bacteria^ though in one of the drops examined there was a delicate tailed-monad in active movement a speci- men of Monas lens^ in fact, y^/' in diameter, having 1 It was owing to the appearance of the pellicle and the seeming likelihood of its breaking up and sinking to the bottom of the vessel, as others had done, if allowed to remain, that I was induced to open this tube so early. I thought it possible that nothing else might form after- wards, and felt anxious to examine the pellicle before it became mixed with the granular deposit. THE BEGINNINGS OF LIFE. 459 a distinct vacuoie in the midst of the granular contents of the cell, and a rapidly-moving flagellum. Experiment t. An infusion of hay. When taken from the digester there was a considerable quantity of brownish-black, charred, organic matter at the bottom of the flask, though the fluid itself was clear and of a dark sherry colour. The flask was opened on the fourteenth day and for six or seven days previously a slight scum had been seen covering part of the surface of the fluid, the solu- tion itself remaining clear. The fluid was found to be quite strongly acid, whilst its odour was sour and not at all hay-like. The scum was found to be composed of mere charred granules and globules, and no trace of organisms could be found either in the fluid or amongst the deposit l . Experiment u. A solution containing fifteen grains of ammonic carbonate, and five grains of sodic phosphate, in one ounce of distilled water. When taken from the digester the glass of the tube was found to be considerably corroded, and there was 1 This infusion had been evidently wholly altered in quality by the high temperature to which it had been exposed ; and from the fact that it was left in an open flask for more than a week, and was still found to be free from any trace of living things, its original sterility cannot be wondered at. It is easy enough to believe that the different organic compounds existing in different infusions would be differently capable of resisting the destructive influence of heat ; so that some infusions may be much more favourable than others for experiments in which high temperatures are resorted to. 460 THE BEGINNINGS OF LIFE. a whitish deposit as a result of this. After a few weeks many bluish cloudlike masses became visible in the fluid, dotted here and there with minute whitish spots, but no pellicle made its appearance on the surface. The flask was opened at the end of the fifteenth week, no apparent change having taken place. On micro- scopical examination the flakes were found to have a very minutely granular composition, and the whitish spots on them consisted of aggregations of minute linear crystals, about 2-wuV' m length. The deposit was composed of amorphous particles and spherules, but there was no trace of the existence of living things l . Experiment v. A solution of eight grains of ammonic carbonate and three grains of sodic phosphate in one ounce of distilled water. When taken from the digester the glass was not in the least corroded. The tube was opened at the ex- piration of eight weeks, when the vacuum was found to be well preserved. There was a very small amount of whitish deposit at the bottom and sides of the tube, though there never had been any trace of scum on the surface. When examined microscopically the deposit was found to be composed of more or less rounded refractive particles, imbedded in a homogeneous colour- less matrix. There were also very many motionless rod- 1 This tube was one of English glass. The quality of the solution must have been altogether altered by the corrosion a great part, if not the whole, of the phosphoric acid being precipitated in the form of insoluble phosphate of lead. THE BEGINNINGS OF LIFE. 461 like bodies from -g^Vo" to TT Vs" in length (crystalline ?), but no trace of living things, either amongst them or suspended in the fluid itself. Experiment w. A solution containing an unweighed quantity of ammonic carbonate and sodic phosphate in distilled water. The fluid was at first somewhat whitish and clouded. From the twentieth to the thirtieth day a thin pellicle had been seen gradually accumulating on its surface; and in the latter four or five days this increased much in thickness, and gradually assumed a distinct mucoid appearance. The fluid itself was tolerably clear, though an apparent turbidity was given by the presence of a fine whitish deposit on the sides of the glass. The flask was opened on the thirtieth day, and the reaction of the fluid was then found to be neutral. When submitted to microscopical examination portions of the pellicle were seen to be made up of large, irregular, and highly-refractive particles, imbedded in a transparent jelly-like material. The particles were most varied in size and shape, many of them being variously branched and knobbed. Several very delicate perfectly hyaline vesicles about YFOO" * n diameter, altogether free from solid contents, were seen ; and, in addition, there were a number of figure-of-8 bodies, exhibiting tolerably active vibrations, each half of which was about 3- % o" ^ n diameter. A subsequent careful examination, on the same evening, of a quantity of the granular matter of the 462 THE BEGINNINGS OF LIFE. pellicle (which had been mounted on two microscope- slips, and at once protected by surrounding the covering glasses with cement)., revealed five spherical or ovoid spores, the average size of which was about -^^W in diameter. They all possessed a more or less perfectly- 8 8 FIG. 36. Spore-like bodies, and figure-of-8 particles, from a solution of Ammonic Carbonate and Sodic Phosphate. ( x 600.) formed nucleus, and all showed a most distinct doubly- contoured wall. One of the smaller of them showed that it had reached a stage when it was about to germinate. In addition, a small mass of Sarcina-like material was seen, which was not very distinctly de- fined, owing to its being still in a somewhat embry- onic stage. Experiment x. A solution containing eight grains of ammonic carbonate and three grains of sodic phosphate. The vacuum having been ascertained to be well preserved, the tube was opened in the beginning of the eleventh week. There was no pellicle or scum of any kind, and no turbidity, though there was a very small amount of deposit at the bottom of the vessel. The reaction of the fluid was decidedly though not THE BEGINNINGS OF LIFE. 463 strongly alkaline. On microscopical examination., the deposit was found to be principally made up of mere amorphous granules separate, as well as forming ag- gregations of various sizes. Here and there, however, there were granules, both separate and aggregated, of a much less refractive character, and more closely re- sembling organic particles. Short homogeneous fila- ments, having all the appearance of Leptothrix, were seen to project from two or three of the granule heaps. FIG. 37. Bacteria, Leptothrix, and Spore-like bodies found in a Solution of Ammonia Carbonate and Sodic Phosphate. ( X 800.) Several Bacteria, some of medium size, and others some- what large and unjointed, were observed, flitting across the field of view with quite rapid undulating move- ments, whilst others were seen rapidly rotating on their long axis. There were also many figure-of-8 shaped bodies which showed distinct and slightly pro- gressive movements quite different from those which are called c Brownian ' though many single particles were seen which soon ceased to exhibit movements of any kind. In addition, there were several spore-like 464 THE BEGINNINGS OF LIFE. bodies having doubly-contoured walls, which were also similar to those of the last solution. 'Experiment y. A solution containing an unweighed quantity of ammonic tartrate and sodic phosphate in distilled water. The solution in this tube was at first quite colourless, clear, and free from visible deposit. About the fifth or sixth day, however, after it had been suspended in a warm place, a number of small, pale, bluish-white flocculi made their appearance throughout the solution, and continued always in the same situation except when the fluid was shaken, owing apparently to their specific weight being the same as that of the fluid itself. The contents of the tube were repeatedly scanned with the greatest care with the aid of a lens, though nothing else could be seen until about the expiration of a month. Then there was observed, attached to one of the flocculi, about " from the bottom of the vessel, a small, opaque, whitish speck, scarcely bigger than a pin's point. This seemed to increase very slowly in size for the next three or four weeks, and then another smaller mass was also per- ceived. At the expiration of this time the larger mass was more than |" in diameter. Both could be, and were, seen by several people with the naked eye. During the three weeks immediately preceding the opening of the flask, it was often remarked that the mass did not appear to have undergone any increase in size. THE BEGINNINGS OF LIFE. 465 It was found that the tube acted as a water-hammer only to a trifling extent before it was opened, though, when the narrow end of the tube was broken off, there was a slight dull report, and a quantity of small particles of glass were swept by the in-rush of air into the fluid. There had still, then, been a partial vacuum in the tube. The reaction of the fluid was found to be slightly acid. This tube was opened in Dr. Sharpey's presence. He had examined the white masses previously with a pocket-lens, and when the vessel was broken the larger white mass issued with some of the first portions of the fluid, which were poured into a large watch-glass. It was at once taken up on the point of a penknife and transferred to a clean glass slip, where it was im- mersed in a drop of the experimental fluid and then protected by a thin glass cover. On microscopical examination, we at once saw that the whitish mass was composed of a number of rounded and ovoidal spores, with mycelial filaments issuing from them, in all stages of development. The spores varied much in shape and dimensions j the prevalent size being about STIR/' * n diameter, though one was seen as much as TnyV/' in diameter. They all possessed a single and rather large nucleus, which was mostly made up of an aggregation of granular particles. Some were just begin- ning to develop mycelial filaments j others had already given origin to such filaments, which were about ^V^" in diameter, and in which were scattered some colour- VOL. i. H h 466 THE BEGINNINGS OF LIFE. less protoplasmic granules, but no vacuoles. Contiguous to these fresh and evidently living portions of the plant, there were other parts in all stages of decay, in which FIG. 38. Fungus found in a solution of Ammonic Tartrate and Sodic Phosphate. ( X 600.) the remains of the filaments were seen in the form of more or less irregular rows of brownish granules representing the altered protoplasmic contents of a previous filament, whose walls were now often scarcely visible. Subsequently the' smaller white mass was picked out, and this was found to contain some living mycelium and spores, and also a considerable patch of decaying filaments, in connection with which there THE BEGINNINGS OF LIFE. 467 was a long and broader filament bearing at its distal extremity a large aggregation of more than 100 spores, quite naked, and very similar in character to those from which the mycelial thread arose. This plant was evidently a Penici Ilium, quite similar to what had been obtained from other ammonic tartrate and sodic phos- phate solutions 1 . The delicate flocculi that first made 1 I have ascertained that the life of this particular fungus is destroyed by exposure for a few minutes to the influence of boiling water. Placed even in a mere corked flask, containing an ammonic tartrate solution, the boiled fungus does not grow, whilst an unboiled specimen will slowly increase and grow in all directions. (The extremely slow growth of the fungus in this solution is very remarkable, when compared with the rapidity with which other minute fungi increase in organic solutions.) A specimen which had been boiled for 5" was kept under observation for nearly three months, and it showed not the slightest signs of growth. Mere exposure to the influence of boiling water for a few minutes suffices to break up and disperse such heads of fructification as are represented in Fig. 38, and also to produce some amount of disorganization of the filaments. How much more, therefore, does it seem likely that an exposure to 1 46-1 5 3 C for four hours, should prove destructive even to mere organic forms ? With the view of answering this question, I placed a quantity of a small fungus, consisting of mycelial filaments and multi- tudes of spores (closely resembling, although not quite so delicate as those which were met with in the saline mixtures), into a solution, of the same strength as that which had been previously employed, of tartrate of ammonia and phosphate of soda in distilled water, and then handed it over to Dr. Frankland with the request that he would kindly treat this in the same way as he had done the other solutions. Accordingly, on May u, a vacuum having been produced within the flask before it was hermetically sealed, the solution was submitted in the s sme digester to a temperature of 146-1 53 C for four hours. When taken from the digester, the previously whitish mass of fungus filaments and spores had assumed a decidedly brownish colour, and it was in great part converted into mere debris. On the following morning the flask was broken, and some of the remains of the fungus and its spores were H h 2 468 THE BEGINNINGS OF LIFE. their appearance in the solution, and which persisted throughout, were gelatinous and made up of aggre- gations of the finest granules. These, however, became almost invisible when mounted in glycerine and car- bolic acid. Experiment z. A solution containing eight grains of ammonic tartrate, and three grains of sodic phosphate, in one ounce of New River water (from the tap). On dissolving the crystals in this water, a small amount of fine white precipitate was produced. After the tube was taken from the digester a fine white de- posit soon subsided. No cloud-like flocculi appeared, and no further change was discovered in the solution. The tube was opened on the sixty-sixth day, after the vacuum had been ascertained to be still well preserved. The fluid had a neutral reaction, and on microscopical examination no living things could be found, either in it or amongst the amorphous granules of the sediment ] . In addition to the experiments now recorded, I have performed twenty others in which the tubes and solu- examined microscopically. Tie plant was completely disorganised : not a single entire spore could be found ; they were all broken up into small and more or less irregular particles, and the filaments were more or less empty containing no definite contents, and being only represented by torn tubular fragments of various sizes. 1 New River water was used in this case with the view of seeing how the results would be modified. It probably contained too much lime- salts and other saline constituents. Germs, of course, may have been present in abundance, and yet no living things were subsequently to be found. THE BEGINNINGS OF LIFg. 469 tions were exposed to still higher temperatures. In fourteen of these they were heated to a temperature ranging as high as 327F (i64C) for four hours, whilst in the other six they were maintained at a temperature of 464 F (240 C) for one hour 1 . Some only of each set have been opened, but all of these were wholly devoid of living things. The infusions of hay and turnip which have been heated to the lower temperature of 327 F were almost hopelessly changed by this amount of heat. When taken from the digester, the previously clear and colourless turnip infusions, for instance, were of a brownish-black colour j owing to the abundant presence of granules and flakes of charred organic matter, which, after complete sub- sidence, occupied a space equal in bulk to one-fourth of the supernatant brown fluid. Infusions of hay were 1 The latter tubes had been sealed in the blow-pipe flame during the ebullition of their contained fluids. Each was then placed in a very thick iron tube, whose internal diameter was only slightly larger than the glass, and into which some of the experimental fluid was also poured. Each iron tube was fitted with a screw-cap, which was firmly fastened by means of long iron wrenches, whilst the tube itself was secured in a vice. The hermetically sealed glass tube was thus enclosed within a her- metically closed iron tube, and by putting the same kind of fluid within each, an equal pressure was ensured upon the inner and the outer surfaces of the glass. All the tubes were then placed in an iron vessel containing five quarts of the very best French Colza oil, which was maintained, by means of gas burners, at a temperature of 464 F for one hour. Although the oil did not boil, the vapours which were given off at this temperature were most disagreeable and suffocating, and made me feel faint and giddy for several hours afterwards. Oils of inferior quality are not available, because they actually boil at much lower temperatures. H h 3 470 THE BEGINNINGS OF LIFE. charred to a similar extent. Infusions of mutton, however, were scarcely altered in colour by this tempe- rature or by the higher one of 464 F, and only a small amount of a light flocculent precipitate was thrown down. But on opening these flasks, the mutton infu- sion in each case presented a very strongly ammoniacal and otherwise unpleasant odour, and was also alkaline in reaction. The organic compounds had, therefore, been differently decomposed in these cases in the hay and turnip infusions more or less pure carbon had been liberated, whilst the mutton solution probably broke up, in the main, into ammonia and carbonic anhydride. Seeing that the organic matter was so thoroughly destroyed in these infusions, there was not much chance that any mere shreds of it should have escaped uninjured in the tubes which contained various saline solutions. And in those experiments in which the tubes and their solutions were raised to the temperature of 464 F, all the disadvantages were further augmented by the extreme amount of corrosion of the tubes, which took place even when the hardest Bohemian glass was employed. Confining ourselves, therefore, to a consideration of the experiments in which the closed flasks containing the experimental fluids have been heated to tempera- tures ranging from 27o-3O7F, the results arrived at must be looked at from two or three different points of view. THE BEGINNINGS OF LIFE. 471 Living organisms have, undoubtedly, been obtained from hermetically sealed flasks which had been heated for various periods to such temperatures; and many persons have been not a little surprised at the com- paratively high forms of life which have presented themselves. This of itself has been deemed by some to be a difficulty of so serious a nature as to make them hesitate to accept the results of the experiments principally on account of a preconceived notion that such organisms could not arise de novo and without ordinary parentage. Although willing to concede that the very simplest organisms might so arise, they are quite indisposed to believe that some of the higher forms which I have represented could have had an independent origin. I will not, however, at present enter upon this question, but will merely state that such difficulties are likely to disappear on a more thorough consideration of the subject as it is hoped the reader will perceive after a perusal of Chaps, xiii. xiv. and xv. Limiting ourselves at present to the fact that specks of living matter must either have been born in the experimental fluids after they had been exposed to the heat, or else (having pre-existed in the fluids) have braved its influence, we have merely again to consider which of these alternatives is the more probable. A choice must be made, and yet, as Prof. Wyman has pointed out, it does not appear at first sight that a profitable resort can be made to arguments from analogy. 472 THE BEGINNINGS OF LIFE. He says ! : ' If, on the one hand, it is urged that all organisms, in so far as the early history of them is known, are derived from ova, and therefore from analogy, we must ascribe a similar origin to these minute beings whose early history we do not know; it may be urged with equal force, on the other hand, that all ova and spores, in so far as we know anything about them, are destroyed by prolonged boiling : there- fore from analogy we are equally bound to infer that Vibrios, Bacteriums, &c., could not have been derived from ova, since these would all have been destroyed by the conditions to which they have been subjected. The argument from analogy is as strong in the one case as in the other.' We do not think, however, that the analogical arguments are so nearly balanced as Prof. Wyman appears to consider them. Whilst it would contradict all our previous experience, and violate the uniformity of natural laws, if certain pre-existing germs had been able to survive the exposure to which they must have been subjected in my experimental flasks, it would in no way outrage our experience if we found that specks of living matter might form de novo in some fluids, just as specks of crystalline matter form in other fluids especially as they do actually appear, under the micro- scope, to arise in this way. The physical doctrines of life which are now so widely believed in, speak unhesi- 1 'American Journal of Science and Art,' July, 1862. THE BEGINNINGS OF LIFE. 473 tatingly in favour of the latter possibility. So that we have an analogical argument of great force, and, in addition, most overwhelming experimental evidence, tending to oppose a mere dogma (omne vivum ex vivo) which many erroneously believe to be a legitimate inference from every-day experience. I say that this inference is erroneous, because, whilst we do know something about the ability which most organisms possess of reproducing similar organisms, we cannot possibly say, from direct observation, that every organism which exists has had a similar mode of origin. The cases in which organisms may have originated de novo are the very cases in which their mode of origin must elude our observation; for it can actually be shown that some organisms make their appearance in fluids after precisely the same fashion as crystals that is to say, they can be seen to arise independently of all pre-existing visible germs l . Germs, therefore, which cannot be seen, and which nobody knows, are not only presumed to exist, but (contrary to all evidence) they are to be deemed capable of resisting the influence of far higher tempe- 1 Having made this announcement on a previous occasion, and having had the satisfaction of finding it pooh-poohed as an idle state- ment, I, still believing in its truth, am glad to ascertain that others hold the same opinion. Dr. Burdon Sanderson says in a recent Memoir (Thirteenth Report of the Medical Officer of the Privy Council, p. 62) : ' From the most careful and repeated examinations of water known to be zymotic, we have learnt that such waters often contain no elements or particles whatever which can be detected by the microscope.' 474 THE BEGINNINGS OF LIFE. ratures than those which, on other occasions, are uniformly found to be fatal to all germs with which experiment is made, whether visible or invisible. And, moreover, some would have us give credence to these assumptions and improbabilities, in order to stave off a belief in the occurrence of something which would be thoroughly harmonious with all the best biological knowledge of the day. Let the reader finally consider the extent of the contradictions which would be involved by the ac- ceptance of the hypothesis, that the results of my experiments are to be explained by the assumption that some preexisting germs escaped death within the closed flasks, during the fiery ordeal to which they had been submitted. It has been previously shown that Bacteria and Torul#a.s well as their germs, both visible and in- visible 1 are killed by exposure for ten minutes to a temperature of 140 F, and that they are even destroyed by a heat of I25F, when it is prolonged for four hours. It is, moreover, admitted by all persons who have paid an adequate attention to the subject, that all such low organisms as may be met with in the experi- mental fluids, are unable to resist the destructive in- fluence of boiling water. And yet now, in addition to all the evidence previously detailed, we again find living organisms occurring in closed flasks which have been 1 See pp. 331-333- THE BEGINNINGS OF LIFE. 475 exposed to 370 F, and 293 F, and even in others which have been heated to 295-3O7F for four hours. Of these experiments none have, perhaps, yielded more striking results than No. b. Here active ProtamcebUe HARl6'y 8 . JOA I tJ-/b-^7 REC'D BIOS HIM 1 Q *Q7 10 n UUW17 Ol ] Pf UNIVERSITY OF CALIFORNIA, BERKELEY FORM NO. DDO, 50m, 1 1 /94 BERKELEY, CA 94720 U.C. BERKELEY LIBRARIES etonaqe \J