156 PARASITES OF MAN 



flesh is, therefore, urgently recommended as a public preventive 

 against all danger from Trichinae." 



As a summary the above conclusions are well nigh exhaustive; 

 but whilst I purposely avoid entering into mere clinical details, 

 there are points of hygienic interest to which I must allude. 

 Thus, as regards the number of larval Trichinae in any one 

 " bearer " at a time, this, of course, must be extremely variable, 

 but it may amount to many millions. In one of the cats on 

 which Leuckart experimented, he estimated a single ounce of 

 its muscle-flesh to harbour no less than 325,000 Trichinae. I 

 find that a relatively similar degree of infection in an ordinary 

 human " bearer" would yield thirty millions. In the case of one 

 of my own experimental animals, a pig, I reckoned that there 

 were at least sixteen millions of Trichinae. The larvae were about 

 ten months old and enclosed within perfectly formed capsules ; 

 nevertheless, the animal had never displayed any symptom of 

 irritation. In a trichinised human subject, examined by Dr 

 Thudichum, it was estimated that 40,000,000 parasites were 

 present. My own estimate, calculated from specimens of 

 muscle obtained from the same case, gave 100,000,000 as the 

 approximate number of worms present. In the only outbreak 

 of Trichinosis occurring in England, details of which will be 

 given further on, I found that the flesh of the hog that had 

 caused the local endemic contained upwards of 80,000 Trichinae 

 to the ounce. The consumption of a pound of such flesh 

 would be capable of producing a collective progeny of some- 

 thing like 400,000,000 within the human " bearer." 



In the year 1865 I conducted a series of experiments upon 

 upwards of a score of animals, including seven birds, the latter 

 all yielding only negative results. So far as muscle-Trichinae 

 were concerned my experiences accorded with those of Professors 

 H. A. Pagenstecher and C. J. Fuchs, at the Zoological Institute 

 in Heidelberg. These experimenters found that the ingested 

 muscle- Trichinae acquired sexual maturity within the intestinal 

 canal of their avian "hosts;" but they never found young 

 Trichinae in the muscles of the birds, nor did they perceive 

 any evidences of an attempt on the part of the escaped embryos 

 to effect a wandering or active migration on their own account. 

 Clearly, if the bird's intestinal canal were a proper territory 

 for the residence of sexually mature Trichinae, we should have 

 found abundance of wandering non-encapsuled flesh-worms and 

 also sexually-immature muscle-Trichinae enclosed in well-formed 



