“At the last meeting, held on April 23rd, I made a statement to the Medical and Surgical Society of Turin, of the results of other experiments tried by heating at M. Schulze’s table and by the imbibitions with the neutral tincture of carmine, through which I came to the conclusion that the Cysticerci of the Tænia mediocanellata die sometimes at 44° C., now and then at 45° C., and always at 46° C. I therefore concluded that they could in no case survive at 47° C. and 48° C. when they were maintained at this temperature at least five minutes. But to the end of more fully corroborating the facts I had thus communicated, I, contemporaneously with these, made some breeding experiments with the same Cysticerci on bold and courageous students who generously offered themselves for the benefit of science.
“Consequently I am now enabled to state that neither Mr Gemelli nor Dr Ragni contracted the Tænia, though each of them had eaten a Cysticercus of the Tænia mediocanellata previously, and respectively subjected to a temperature of 45° C. and 47° C. The larvæ were properly prepared and submitted to gradual heating on the above-mentioned table, and swallowed when they no longer gave signs of life. In like manner no generation of the Tænia took place in the body of Mr Martini, who ate the Cysticercus brought to a temperature of 44° C. It was maintained at this degree of heat during a period of about three minutes, and swallowed whilst a very slight movement was still visible in a portion of its neck.
“In another student, on the contrary, who ate a living Cysticercus of the Tænia mediocanellata, the tapeworm reached its maturation in fifty-four days and eliminated the two first proglottides. It threw off two more on the fifty-eighth day, and thirty on the sixtieth. Sixty-seven days after swallowing the Cysticercus this courageous young man, having, like his three companions, taken some kousso and castor oil, emitted the strobila. It was furnished with 866 rings, but destitute of the neck and head. Its measurement afforded a total length of 4·274 mètres.
“Adding now to the 866 proglottides the thirty-four already eliminated, 900 would be the number of the segments; and reckoning the length of each of the latter to be fourteen millimètres, we should have had the strobila (deprived of the head and neck) reaching a length of 4·75 mètres. Further, calculating the head and neck to be eight millimètres long, a total length of 4·83 mètres would be the result.
“From all these facts we may conclude that the Tænia has, in our instance, reached an approximative length of seventy-two millimètres a day, affording a daily production of 13·43 proglottides.”
In relation to requirements of state medicine I have thought Perroncito’s researches sufficiently valuable to be quoted at some length; but their chief interest culminates in the worm- feeding experiments. Excellent in all respects as was the conduct of the medical students who, with Professor Perroncito’s approval, swallowed living specimens of the Cysticercus bovis, the intentional ingestion of beef measles is by no means a novelty. Eight or ten years back Dr Oliver (after explaining to one of the selected victims the possible consequences of the experiment) induced a Mahommedan syce or groom and a Hindoo boy to swallow perfectly fresh and living beef measles. In this way Dr Oliver successfully reared the Tænia mediocanellata in India, and he was thus enabled to fix the amount of time necessary for the full growth of the strobila. Many other persons have displayed an equal amount of zeal in the cause of helminthology, by partaking of the larvæ or germs of other parasites. Thus, at the risk of repetition, I may state that Möller many years ago swallowed the slender-necked hydatid (Cysticercus tenuicollis) in the hope of infesting himself with Tænia marginata. Several persons have defiantly swallowed trichinised flesh. Professor Leuckart and some of his pupils also courageously swallowed the eggs of Oxyurides, and they had the infinite satisfaction of noticing the young worms in their fæcal discharges some fifteen days afterwards. Dr Crisp ate part of the cooked flesh of an animal that had died of cattle plague, and I myself partook of moderately cooked meat which I knew to be swarming with psorosperms. These obscure organisms were by some persons considered to be either a cause or product of the rinderpest. They will be noticed in my account of the Protozoal parasites.
For the purpose of advancing science and the welfare of the people, there are scores of persons always to be found ready to make personal sacrifices of the kind undertaken by Drs Ragni, Martini, and Gemelli. Unfortunately for English science there are not wanting people in this country who are prepared to threaten with fines and imprisonment any savant who may think it desirable to perform a similar set of feeding experiments on animals. Invaluable for good as our experimental investigations have already been, it would seem as if it were the deliberate aim of these sentimental obstructives to put a stop to the acquisition of all useful knowledge in the future.
In reference to the rate of growth of tapeworms, Professor Perroncito’s determinations are useful, inasmuch as they verify certain ascertained facts with precision and confirm the general conclusion that had been drawn by practical helminthologists from various sources of information. In regard to the number of proglottides proper to a sexually mature tapeworm, the circumstance that Perroncito’s calculation was made without the head and a portion of the neck of the worm being present shows that it cannot be relied on absolutely; nevertheless, as far as it goes, it tends to confirm what Leuckart had long previously stated. I have possessed myself of upwards of thirty perfect beef tapeworms expelled from my patients, and in some of the specimens it was noticed that the segmentation-rings in the region of the neck were far more crowded together than they were in others. I also possess a perfect Tænia mediocanellata, removed post mortem. Though the rate of growth may be the same from day to day, yet experience has shown that the number of proglottides actually cast off varies exceedingly. Küchenmeister’s estimate of the average number agrees in the main with what we have ourselves observed (five to twenty daily); and here again Perroncito’s investigations serve to verify the general correctness of our previous determinations.
To return to Pellizzari’s researches, one of the most important questions is that which relates to the prevalence of tapeworm. In this connection he first brings forward some very interesting and instructive data that had been previously communicated to the Medico-Physical Academy of Florence by Professor Marchi. On the occasion referred to Marchi had stated that, out of thirty-five Tæniæ which he had examined, only one belonged to the species known as Tænia solium; all the other thirty-four being of the unarmed type, or Tænia mediocanellata. Reflecting on this striking fact, and also on the circumstance that he had in vain begged his colleagues to send him specimens of Tænia solium, Marchi seems to have missed the very palpable explanation of this otherwise strange phenomenon. “How does it happen,” exclaimed Marchi, “that, notwithstanding the occurrence of 13,000 kilogrammes of the flesh of measled hogs in the public butcheries, I have seen but one specimen of Tænia solium, whilst thirty-four cannot have originated from the pig?” “The wherefore is obvious enough,” replies Pellizzari, “because our hygienic regulations demand that the flesh of the hogs be raised to a temperature of 60° Cent. (140° Fahr.);” and he then himself immediately proceeds to ask another question, namely, as to how it happens that the Tænia solium is so frequently seen in other places. To his own question Pellizzari responds by remarking—(1) that there are not so many precautions (of a sanitary kind) taken in other places; and (2) that the people elsewhere consume more slightly salted or uncooked meat, as sausages and so forth (come salame giovane, salciccia e via dicendo). Pellizzari, having explained that Marchi’s thirty-four tapeworms must all have arisen from the consumption of the Cysticercus of the ox, then goes on to speak of the prevalence of tapeworm in Florence, even in little children. This last-named feature, he says, is due to the circumstance that raw meat is frequently employed as a restorative (come cura ricostituente). “Thirty years ago,” remarks Professor Pellizzari, “it was just as difficult to find a single Tænia mediocanellata as it is now easy to find a great number of these worms; and all because it is nowadays customary to eat the flesh of the ox either insufficiently cooked or raw. This absolute inversion of the facts of the case affords proof of the correctness of the position sustained by me, to the effect that the cooking of meat up to the degree of temperature necessary for ebullition ensures the destruction of the Cysticerci.” Notwithstanding this statement of his own, Pellizzari thinks that the interference of inspectors may be pushed too far, and thus serve to bring about the very disasters which it should be their supreme object to prevent. Thus, he argues against the suggestions of those who would entirely prevent the sale of measly meat, and who would only permit, as obtains in the province of Modena, the melting down of the fat of hogs. Very strict measures of this sort would, as he says, constitute a radical means of entirely stamping out Tænia, but he also very judiciously reminds the sanitarian (igienista) that “such a step would be a serious thing for the tradesman, bringing injury not only to the municipal administration, but also proving an encouragement to smuggling. In this way the public health would sustain worse injury by the inducement held out to the owners of infected animals to slaughter them in secret butcheries, thus little by little withdrawing the meat from the superintendence of the public officials. By the adoption of fraudulent measures there would be a daily consumption of diseased meat; and thus also, while the public administration would suffer loss, the public health, on the other hand, would gain nothing.” In effect Pellizzari says, if we advise the employment of more severe and radical measures than those already in vogue in Florence, we should overburden the tradesman, almost compel him to defraud the exchequer by smuggling, and greatly injure the public health.
The facts and explanations advanced by Italian writers regarding the causes of the endemic prevalence of tapeworm, are in perfect harmony with those previously obtained from other sources. Respecting these causes there is much that is both new and interesting. The eighth annual report of the sanitary commissioner of the Government of India had already made us acquainted with the fact that during the year 1869, out of 13,818 head of cattle slaughtered in the stations of the Upper Punjab, 768 beasts were found to be infected with measle-cysts. This, as I have remarked (Tommasi’s edit., p. 54), “affords a rate of 5·55 per cent., being a considerable diminution of the proportion observed in 1868, when the percentage gave a total of 6·12. The reduction was, without doubt, due to the vigilance and enlightenment of the army meat inspectors. The prevalence, however, of tapeworm does not bear relation to the number of animals infested with Cysticerci so much as to the actual number of Cysticerci developed in infected animals. I have frequently pointed out the inadvisability of condemning and burying the carcases of measly oxen, whether there be few or many Cysticerci present, and I have stated, on trustworthy evidence, that even the presence of a few Cysticerci is deemed by some inspectors a sufficient reason for rejecting the entire animal. Such a waste should never be allowed. In regard to the numbers of ox-measles present in particular instances, I have elsewhere adduced some remarkable facts communicated to me by Dr Joseph Fleming, of the Indian Army Medical Staff. None of my experimental animals, though fed with scores of ripe proglottides, yielded such an abundance of Cysticerci as Dr Fleming encountered in Punjab cattle. In one pound weight of the psoas muscles Fleming counted no less than 300 Cysticerci.” From this it follows that the flesh of a largely infested animal is capable, under the circumstances of ration distribution and imperfect cooking, of originating numerous tapeworms.