INSECTS INTESTINAL WORMS DIAGRAM G 159 



is caused by a worm of very peculiar form wliicli lives in the 

 brain of the sheep, and which is always found in animals which 

 have died of this disease. It is shaped like a bladder full of water 

 as large as a nut or a walnut. It does not move, and is not at 

 first recognised as a worm, but nevertheless is one. When this 

 bladder is opened, several white prolongations are noticed in the 

 interior ; and if one is torn with the point of a pin, we find a head 

 just like that of the tapeworm in the centre of each. 



Other worms live in the flesh and often in the lard of the 

 hog. They also are bladder-shaped, but not larger than peas or 

 at most than nuts. Like the worm which produces the staggers, 

 these also have a concealed head exactly like that of the taenia. 

 But the most formidable parasite of the hog is the trichina 

 spiralis, which is found in the muscles, and when taken alive into 

 the human body in any number, has frequently caused speedy 

 death. ^ All worms which thus live in the flesh of animals may 

 become dangerous to man when swallowed, if the meat which 

 contains them has not been sufficiently cooked. All meat used 

 for food ought to be well cooked ; and badly cooked, or only 

 smoked meat should be avoided. All meat which is suspected to 

 be diseased, or to contain worms, ought to be well boiled for a 

 considerable time, after which it may be eaten with impunity. 



