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 ON 
 
 TRICHINA SPIRALIS. 
 
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 y/ BY 
 
 J. BAKER EDWARDS, Ph. D., F.CS. 
 
 (Lato Locturor on Chemistry and Medical Jurisprudence at the Royal Infirmary 
 School of Medicine, Liverpool, England.) 
 
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ON TRICHINA SPIRALIS. 
 
 B? J. Baker Edwards, Ph. 0., F. C.S., 
 (Late Lecturer od Chemistry and Minlical Jurispruilonco at the Royal 
 lufirmary School of MmliciDO, Liverpool, Rnglaiul.) 
 
 Tlic occurrence of two fatnl oases of Trichiniasis at Hamilton, 
 Ont., and the Huccessful treatment of several cases in Montreal, 
 have drawn fresh attention to the parasite causing this disease; 
 and as the researches into its natural history are somewhat 
 scattered, it is thought a short rcsumi may not be uninteresting 
 to our readers. 
 
 The cysts containing this parasite, and forming its sarcophagus 
 in the flesh, were observed and examined microscopically by 
 Tiedman. in 1822. The.sc were found in human muscle after 
 death, and occasioned much speculation as to their real nature. 
 In 1835 they were minutely examined by Mr. James Paget, and 
 described and named by Professor Owen ;* but as there then 
 existed no clue to their natural history, they for some years 
 possessed no interest beyond tlie fact of their existence in Imman 
 muscle, and their classification as a genus ol" Entozoa ; belong- 
 ing to the order, Coelelmintlia ; family, Nematoidea. Herbst 
 found, in 1841, that dogs, when fed upon parts of a badger 
 containing these worms, bee i me infested with them in their 
 muscles. But it remained for Zenker, in 1860, to show that 
 the human body bciomes infected with tlicse parasites in 
 
 -\1 
 
 • Trans. Linnean >Socy., LXXX., LX.tXIV. 
 
 i 
 
7 
 
 consequence ol' catinj; pork nlreiidy containing tlieni. Since 
 this time, thousands of deaths have been traced to this cauHc, 
 which would previously have been attributed to typhoid, trastrie, 
 or rheumatic lever, paralysis, poisoiiiufr. or atropliy. Further 
 researches by Virchow of lY'rlin and Leuekart of Giesscn, added 
 ^.neatly to our knowledj^c of the natural history of the species, and 
 Prof. Daltou has elaborately studied eases of the disease in New 
 Yoik. 
 
 Ti khinvis'tH is now fully established us one of the " ills which 
 flesli is heir to." Iti several hospital examinations of human 
 bodies after death from various causes, from 2 to 3 per cent, of 
 adults are found to ct)ntain old encrusted capsules containing 
 these worms, thus bearing evidence of the existence of this disease 
 at some former period. In the Chicago market u medical com- 
 mission found in the pork offered for sale 2 per cent, of flesh thuj 
 infected. 
 
 From tliese facts it may be inferred that the disease occurs 
 much more frefjuently than lias heretofore been supposed, but 
 that it is only under peculiar circumstances that the worm breeds 
 with such excessive rapidity as to cause fatal or even serious 
 results. 
 
 The cases of the disease which have recently occurred on this 
 Continent have caused still further investigations to be made as 
 to its character, the probability of its detection, and the means of 
 cure. Of these cases, those which occurred in the west were fatal, 
 but those in Montreal, being of a slight nature and speedily 
 diagnosed, were treated successfully. The whole literature of tlie 
 question has been searched for an explanation of the facts which 
 presented themselves in the Montreal cases, and whilst they are 
 tbund to be in general accordance with cases on record, in some 
 respects they may be con.sidered unique. The history of the 
 Montreal cases may be concisely stated thus: 
 
 On Wednesday, the 24tli of March, a family in a boarding- 
 house partook of some liastily-fried ham. Within an hour 
 afterwards two of the adults felt nauseated and had some pain in 
 tlie stomach. One took a large dose of brandy, and vomited his 
 dinner; the other felt only abdominal pain, .spasms, and faint- 
 ness. He returned from his work and went to bed. During the 
 night his wife and wife's mother felt ill, and suffered from pains 
 in the bowels, together with great feverishness and thirst. During 
 the following day, five other persons, who had p rtaken of the same 
 
 I 
 
meal, suffcrod iiinrc or less from similar symptoms, .iiid in the 
 cvciiirifi; of Thursday called in a physician, who, after careful 
 enquiry, diagnosed Tricliin'asis, and called in a second opinion 
 on the case. On Good Friday a slice of ham was submitted to 
 me for microscopic examination, in which I discovered, after 
 some hours' investii;ation, several characteristic specimens of 
 Trichina spiralis. By Monday mornin,;,', with the assistance of 
 my friend M'- Ritchie, I had found several ^Toups of Trichina, 
 both in the free state and partially, as well as fully, encysted. 
 Tlicse were durinj; the same day shown to a considerable imniber 
 of medical friends. 
 
 Mr. C. Baillic kindly placed liis inicro-photo<rraphic apparatus 
 at my disposal, and durinj:; the week produced some excellent 
 nejratives of the worms " in situ " in the pork jnusele. 
 
 No. 1. — This photof^raph (reproduced by Mr. Iuu,!is) shows a 
 croup of Trichinae in very close proximity, travellinf; up a line of 
 muscular tissue, or rather between the muscular bundles. 
 
 No. 4 shows an individual worm surrounded by a <relatinou8 
 cyst, protruding his head therefrom, apparently in search of food, 
 for his head and mouth can be distinguished under the 
 microscope in the dark mass of muscle to the right of the field. 
 Above, around and below are the worms not encysted, but 
 curled up in the band of muscle, so that thirteen may be 
 counted on a field of view not exceeding the tenth of an 
 inch in diameter. 
 
 No. 5 shows what appears to be a lateral section of the 
 worm fully encysted, but the worm is really whole, and the 
 section only optical, the cyst being so transparent as to allow 
 focusing through it. The cyst, although perfect, is not 
 calcareous, and in no case did any calcareous cysts present 
 themselves. The above were found in the slice of ham 
 in question, and, indeed, in one particular muscle of that 
 ham, of which the horizontal section did not exceed one- 
 quarter inch in thickness. It is evident, therefore, that the 
 disease was recent in the young pig from which the ham 
 was taken, and that, being in the free and semi-encysted 
 condition, the worms were in a condition to be aroused into 
 action and activity in a much shorter time than liad they 
 been fully and calcareously ency.sted. According to Virchow* 
 
 * Virchow's archives, 1850, vol. xxxiii, page 535. 
 
 / 
 
6 
 
 and /enkiir the period of incubiition of the cyst in the Htoinacli 
 iH from six to ci^^lit days. This liiis been erroneously inter- 
 preted to nic;in that such a period must elapse before any 
 marked symptoms can be reeo<^nized. Such a period of time 
 however, is meant to be inclusive of the rcproducinj; power 
 of each individual, from whose body successive broods of young, 
 numbering from 100 to 20(1. are discharged. Dr. T. 8. 
 Cobbold* has f<mnd a period of sixty nine hours amply suflBcient 
 for the development of the young muscle flesh worms of the 
 human subject into the sexually mature adult Trichina of 
 the dog. If all the worms were calcarcously encysted a 
 delay of from three to six days might be; expected before 
 intestinal irritation was a miirkcd symj)tom. But in cases 
 where the worms are young and free in the muscle, develop- 
 ment may take place in a ftw hours, and rapid multiplication 
 take place before other encysted worms were released from 
 their capsules. 
 
 Thus a succession of fresh irritations to the nmacular and 
 nervous system may be expected from the first few hours to 
 a period of eight or ten weeks. In the fatal cases examined 
 iu Chicago and Hamilton no single case of encysted Trichina 
 was found in the flesh, but in tlie Montreal cases one or two 
 distinct and complete cysts were extracted from the man's leg. 
 This was eight weeks after eating the pork, and when the 
 symptoms had somewhat abiited, but considerable pain still 
 felt iu the muscles. The great sliock to the system, whicl) 
 frequently terminates fatally, appears to result from excessive 
 generation of the worms at any one period; — thus young and 
 healthy persons are frecjuently killed sooner than older and 
 more feeble individuals, the reason being that in the former 
 case probably more ibod is eaten, digestion is more rapid, 
 uausea more readily overcome by active exertion, and tlic 
 breeding of the worms becomes excessive and continuous. In 
 the Hamilton cases the young wo:nan died in three weeks, 
 whilst her mother survived six weeks, after eating the fatal 
 repast. Nos. 2 and 3 in the photograph show examples of 
 the worms in the latter case. In No. 2 the wo.-m is carefully 
 picked out from the muscle. No. 3 shows the musjle containing 
 the worms in various postures on a line of muscle, it also 
 
 • Journal Linnean Society, vol. ix, page 209- 
 
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 shows two <:;cnorations on or near tlic sanio lino of nmsele. 
 The faint eurve near the edge of the margin bciim; a larger 
 nnd^ older worm than the other three, it is but p.irtially in 
 focus, and only about one half is, tlmrefore, seen. 
 
 These worms have been generally figured in wmks on 
 Physiology in two condilinns, viz,, encysted in the imiscle, 
 und sexually developed iu the intestinal canal. The appcaiaLCC 
 of the young sexless worm //( Ininnitu in the flesh has not 
 been carefully described. Some observers have, therefore, 
 mistaken it for another species, whilst others have overlooked 
 it altogether. The photographs Nos. 1, 3, 4 and 5 show 
 fairly the viiried forms in which the worm may be expected 
 to be found in flesh during periods of from one to six weeks 
 after ingestion. After a period of from six to twelve months 
 the cysts become covered with a phosphatic opaque deposit, 
 and the worm can only be seen b) dissection or by solution 
 of the coating in weak acid. These old cysts are sometimes 
 found empty. 
 
 The best medium which I have found for mounting recent 
 muscle for the examination and extraction of specimens, under 
 the microscope, is a mixture of one part glycerine and one part 
 aqueous carbolic acid. The muscle may be conveniently 
 examined by a two-third object glass, and a B. or C. eye 
 piece with the smallest aperture in the diaphragm. The 
 extracted worm is best seen under a J-inch objective, with a 
 small pencil of light, or by polarised light. No. 1 is magnified 
 100 diameters; Nos. 2 and 3, 150 diameters; Nos. 4 and 5, 
 50 diameters. 
 
 In 1866 some valuable experiments were conducted, in 
 reference to the propagation of these worms, by Dr. T. Spencer 
 Cobbold,* whose researches on Cestoid Entozoa place him at 
 the head of English authorities on such subjects. 
 
 After feeding animals with trichinous food, seven experiments 
 on birds all proved negative. Three sheep, two dogs, one 
 pig and one mouse gave also negative results. 
 
 Nine cases were successful, viz., four dogs, two cats, one 
 pig, one Guinea pig and one hedgehog. 
 
 While we may, therefore, conclude that birds and herbivorous 
 mammals are very unlikely subjects for infection by this 
 
 * Jourual of the Liunean Society, Zoology, vol. t), p. 205, 
 
 \, 
 
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 menus ; it \h niso found that otlier nnimiils, ns the dop; iind 
 pin, for instance, niiiy partake of the food nnd yet osoajto 
 infection. This lielps to explain the reeonled facts tliat 
 lurjie parties have eaten of tricliinous food in company, nnd 
 Home have been killed, others suffered slifilitly, and again 
 some escaped alto^etlier. 
 
 Moreover, in the human subjects vxiinimnii posl-inuiinii , where 
 the disease has not proved fatal, in some cases, the cysts were 
 by no means numerous, whilst in others they have been 
 cstimuted at from forty to one liunihed millions. The 
 cxeeHsivc alarm which is apt to seize the public mind by 
 the discovery of a case here and there is not, therefore, 
 justified by the facts when properly understood. At the 
 same time, whatever means can be adojjted by the public 
 nutlioritiea to prevent its becoming a familiar disottHC jn our 
 new Dominion should be forthwith adopted. 
 
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