340 OUR HUMBLE HELPERS 



its flesh, although of inferior quality, its lard and ba- 

 con, can very well be utilized, but care must be taken 

 never to use any of this food without first thoroughly 

 cooking it at a heat intense enough to destroy every 

 dangerous germ. As for the pig itself, it can be 

 kept from the measles by cleanliness, and especially 

 by seeing that it eats no excrement. Every pig that 

 wanders about and feeds on filth deposited along 

 walls may find under its snout some pieces of tsenia, 

 swallow them with the dirty food, and thus become 

 infected with hydatids. 



"To finish this subject, I will tell you of another 

 taenia which in its tape-worm form inhabits the dog's 

 intestines, and in its bladder-like or hydatid stage 

 has its home in the sheep's brain. Grass defiled by 

 the excrement of dogs affected with this taenia re- 

 ceives the eggs of the expelled ripened sections. A 

 sheep comes to browse this grass, and in a few weeks 

 a terrible disease shows itself in the poor animal. 

 With wild eye, driveling mouth, and heavy head, the 

 animal turns round and round, always the same way, 

 and falls gasping on its side. Food no longer 

 tempts it, the blade of grass stops on its bleeding 

 lips. All its efforts to stand up are powerless; it 

 keeps looking for a support, especially for its head, 

 and if this support is lacking it falls after a few 

 turns. This strange disease is called the staggers, 

 from the animal's tendency to turn and turn with 

 staggering motions. 



' ' Now if we open the brain of a sheep that has died 

 of the staggers, we invariably find in the cerebral 



