210 DR. T. S. COBBOLD ON TRICHINA SPIRALIS. 



close of October, 1866, both birds died, wbeu Mr. Pritcliard care- 

 fully examined the flesh of them, but failed to find any trace of 

 Trichinae. 



Exps. 28 and 29. From April 2nd to the 9th of the same month, 

 1866, inclusive, feedings with trichinous pork were likewise given 

 to two more dogs. These animals were destroyed and examined 

 by Mr. Pritchard in November, 1866 ; but the result appeared to 

 be negative. 



Hemarks. —AlthoxLg}i, at first sight, these experiments do not, 

 on the whole, appear to have been so successful as one might 

 desire, yet the results obtained correspond very closely with those 

 obtained by investigators on the continent. Thus the seven 

 experiments on birds (including 5 fowls, 1 goose, and 1 crow) 

 were all negative. This experience, so far as muscle-trichinse are 

 concerned, accords precisely with the results obtained by Pi-ofs. 

 H. A. Pagenstecher and C. J. Puchs at the Zoological Institute 

 in Heidelberg. These experimenters, it is true, found that the in- 

 gested muscle-trichinse acquired sexual matm-ity within the in- 

 testinal 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 

 efi"ect 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, Drs. Pagenstecher and 

 Puchs would have found abundance of wandering and non-encap- 

 suled fleshworms, and we should have obtained (owing to the 

 greater length of time which we generally allowed to elapse before 

 destroying the experimental animals) sexually immature muscle- 

 trichinae enclosed in well formed capsules with, in some instances, ' 

 more or less calcareous degeneration. I have put the matter 

 thus clearly, because not a few persons still entertain the notion 

 that Trichinae are liable to infest all kinds of warm-blooded, and 

 even, also, many kinds of cold-blooded animals, such as reptiles 

 and fishes. Certain nematodes found in earthworms have been 

 described as Trichinae ; and, consequently, pigs and hedgehogs were 

 said to become trichinous through eating these annelids. The 

 minute fleshworms described by Bowman from the muscle of the 

 eel are not true Trichinae, any more than the somewhat similar 

 parasites {Myoryhtes Weismanni) which Eberth found to infest 

 the muscles of the frog. The negative results above obtained may 

 therefore fairly be taken as positive, in one sense, inasmuch as 

 they help us, with the aid of other experiences, to define the area of 



