CYSTICERCI 

 IN WILD RUMINANTS. 



By W. REID BLAIR, D.V.S. 



WHILE the tapeworm in its adult state has been rarely met 

 with among our wild ruminants, its embryo or cystic 

 stage has been of frequent occurrence, causing death in at least 

 two instances. 



No parasite with which we deal has a more interesting life 

 history than the tapeworm, occupying as it does the attention 

 of the practitioner of human medicine as well as the veterinarian. 



A remarkable fact in connection with the life history of the 

 tapeworm is that the eggs will not develop into mature worms 

 in the body of an animal belonging to the species of the one in 

 which they were produced. It is necessary that they should first 

 enter the body of an animal of a different species and there de- 

 velop into embryos, and there they remain in a somewhat ad- 

 vanced state of development until their host dies and is con- 

 sumed by an animal belonging to the species of the original host. 

 They must have a host or bearer and intermediate bearer. In 

 a great majority of cases man and dogs act as hosts, while cattle, 

 pigs, sheep, and deer act as the intermediate bearers. 



The anterior part of the tapeworm is narrow, and presents a 

 terminal swelling by which it attaches itself to the mucous mem- 

 brane of the intestines by means of the suckers and numerous 

 booklets which nearly all tapeworms possess. This anterior 

 swollen part is distinguished as the scolex, popularly called the 

 head of the tapeworm, but it is mainly its external form which 

 entitles it to this name, as there is no alimentary system. The 

 parasite floating in the digested food of its host absorbs soluble 

 material by its general surface. There is neither vascular nor 

 respiratory system, and the body cavity is represented merely by 

 irregular spaces. All tapeworms are hermaphrodite, and most — 

 if not all — are probably self-fertilizing. 



Following the scolex are the segments or proglottides, of which 

 the tapeworm is made up and budded off from the head end, and 



