286 DE. T. S. COBBOLD OlS" ENTOZOA IN THE DOG. 



encountered from time to time in dogs. Until lately the value of 

 such pecuKar statistical records, in reference to our domestic 

 animals, did not fully strike me ; but from 1855 to 1864 inclusive 

 I noted down all the parasites encountered in less common "hosts." 

 Part of the fragmentary results thus obtained I have already com- 

 municated to the Zoological Society *. 



6. Trichina spiralis. — This interesting parasite is probably not 

 indigenous, so to speak, in the dog ; but the ease with which it 

 may be transmitted, and the frequency of its introduction by ex- 

 periment, oblige us now to class the fleshworm with other ca- 

 nine entozoa. Until lately it was supposed that Trichina might 

 be made to infest any warm-blooded animal ; but recent experi- 

 ments (conducted by Mr. Simonds and myself at the Eoyal Ve- 

 terinary College in London, and on a more extended scale by Drs. 

 Pagenstecher and Fuchs at the Zoological Institute at Heidel- 

 berg) incontestably prove that the fleshworm, as such, cannot 

 be reared in birds. Having already offered a detailed account of 

 these experiments to the Society, it is only necessary that I 

 should remark that I have repeatedly reared Trichince in the dog 

 from the flesh of man and animals. Except in a very indirect 

 manner, the dog itself is scarcely likely to communicate the flesh- 

 worm disease to man ; nevertheless if the flesh of a trichinized dog 

 were eaten by us, the malady would be readily propagated. There 

 would moreover be considerable danger in allowing trichinized 

 dogs to roam at large ; for the consumption of their flesh (after 

 death) by other animals, such as rats, for example, would convey 

 the disorder to new " hosts," which again might convey it to the 

 pig, and ultimately to man. It has, indeed, been fully proved 

 that in some instances swine have been infected by eating dead' 

 rats and the decomposing remains of other trichinized animals ; 

 and it is quite certain that rats, not previously made the subject 

 of experiment, have been found to contain Trichince in their 

 muscles. Dr. Krabbe informs me, by letter, that he has dis- 

 covered trichinized rats in Copenhagen ; and the same thing has 

 been noticed in Germany. Dogs and cats alike may also become 

 infected from this source. Bearing in mind, therefore, the variety 

 of sources whence the dog may obtain Trichina, no one need in 

 future be surprised at finding this animal affected with the disease ; 

 and since the malady is so readily transmissible, care should be 

 taken to destroy, thoroughly, all trichinized animal flesh wherever 

 and whenever encountered. In illustration of the facts above 

 * 'Proceedings,' for March 2(3, 1801. 



