ON THE DISORDERS OP THE DIGESTIVE APPARATUS. 133 



be thrown over the floors of the kennels. Three other 

 forms of round-worms are found in the intestines of 

 the dog, but are of much less clinical importance than 

 Ascaris : — 



1. Dochmius trigonocephalus, found in, the stomach and 

 intestine. 



2. Tricocephalus depressiuscuhis, found in the caecum. 



3. Trichina spiralis has been, experimentally, developed 

 in the intestines (and muscles) of the dog.* 



The tapeworms of the dog are numerous and impor- 

 tant. It must be remembered that an animal is not free 

 from them until the head, apparently the most insignifi- 

 cant part, has passed ; so long as this remains attached to 

 the wall of the bowel will it develop fresh egg-producing 

 segments, which are passed per vias naturales and prove 

 the means of diffusion of the parasite. 



Great as are the inconveniences and other troubles 

 produced by the mature tapeworms, their larvae, known 

 as cystic worms, are much more serious, .especially from 

 the point of view of comparative pathology. We may 

 proceed to notice, seriatim, the taeniae of the dog in so far 

 as they have a practical bearing on pathology. 



1. T. cucumerina, so called from its cucumber- shaped 

 segments. It inhabits the small intestines, is a small but 

 very long tapeworm, the segments of which separate when 

 mature, escape through the auus, and then discharge their 

 ova in the coat of the dog, which are ingested by the 

 dog-louse, Trichodectes laMs. 



2. T. csenurus is found in the small intestines. Its 

 ova fall on the grass, are swallowed by sheep, rabbits, 

 cattle, &c, and may give rise to the disease known as 

 " sturdy " or " turnsick." The ova develope into those 

 cystic worms known as the " many -headed gid hydatid," 

 which prefer to reside in the brain. 



3. T. marginata. — Its cystic form is the long-necked 

 bladder-worm found in the peritoneal sac of herbivores, 

 especially sheep. 



* Its occurrence naturally in the muscles of foxes is mentioned in the 

 ' Allegemeinige Med. Cent. Zeitung.' 



