(XEKUUUS CEREBALIS IN CATTLE AND SHEEP. 351 



this disease, which is afforded us by a knowledge of the 

 source whence sheep or cattle derive coenuri, I attempted to 

 convince the farmers, several years back, as to the real cause 

 of the disorder and the ready means of prevention. As the 

 German zoologists had done, I gave dogs the hydatids from 

 the brains of sheep affected with sturdy, and obtained large 

 numbers of tseniae. The joints of tsenia coenurus thus ob- 

 tained were given to lambs, and sturdy was induced in them. 



In 1859 I drew up tables showing the results of many 

 experiments performed in different countries on this subject, 

 and 41 experiments as to the development of tsenia coenurus 

 showed that of about 50 dogs fed on whole or portions of 

 coenuri from the brains of sheep, 33 became affected with 

 tapeworm. As many as 400 taenise have developed from 

 one cyst, and the fourth part of one hydatid swallowed by a 

 dog led to the development of 191 tapeworms.. In less than 

 a fortnight the tapeworms are observed in the intestines, 

 from a line to two in length, showing no trace of joints or 

 transverse folds ; they may attain an inch the third week, 

 and 4 inches the fourth. Worms developed in 155 days are 

 mentioned as being from 2 to 2J feet in length, but by one 

 experiment it was found that this length could be attained 

 by the tapeworm in less than three months. The tsenisB 

 remain in the small, and obtain exit from the body through 

 the large intestine. They are never expelled whole, but 

 separate proglotticles or joints, each of which is charged with 

 many hundred eggs, are evacuated with the faeces. 



Failure in the experiment depends on diarrhoea causing the 

 expulsion of the cyst before the heads can attach themselves 

 and grow. Occasionally a disease such as distemper may 

 prevent the retention of the parasites. 



To demonstrate that the cerebral hydatids are produced by 

 introducing ova from the dog's tapeworms, 39 sheep and 2 



