PARASITES OF ANIMALS. 



97 



but throws down a copious precipitate with a solution of 

 nitrate of silver, owing to its strong impregnation with com- 

 mon salt. These characters apply to no other fluid in the 

 Figure 70. body, whether healthy or morbid." Dr. 

 Murchison. In some cases hydatid tumors 

 situated in the liver and other internal organs 

 have been opened from the exterior, with suc- 

 cess, by skillful surgeons, but these operations 

 are always dangerous and often immediately 

 fatal. The escape of the fluid, with the 

 minute cysts and heads contained in it, into 

 the abdominal cavity, will give rise to other 

 tumors, and thus increase the disease, even if 

 death does not immediately result. 



This is. eminently a case where " an ounce 

 of prevention is worth a pound of cure." The 

 means of prevention are simple, though not 

 easy of application in all cases. The iirst and 

 most important rule is to diminish the num- 

 ber of dogs to the utmost possible extent, and 

 then to keep them at the minimum number ; 

 second, avoid as much as possible the prox- 

 imity of dogs and sheep ; third, avoid feeding 

 dogs with uncooked livers or other offal of 

 sheep containing these parasites, or never give 

 them such raw food without careful exami- 

 nation ; fourth, avoid too much familiarity 

 with dogs, and especially between children 

 and dogs ; fifth,, be careful not to eat lettuce, 

 fallen fruit, or other raw food that has not 

 been thoroughly washed, both on account of 

 this and other parasites j sixth, avoid by all 

 means possible the use of impure water, or water liable to 

 be contaminated by eggs of parasites and excreta of animals, 

 both for household purposes and to supply sheep, cattle, and 

 horses, for such water is not only liable to contain echino- 



Figure 70. Mature Tcenia echinococcus, much enlarged. Hearth and Home, 

 after Leuckart. 



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