218 ANIMAL PARASITES AND MESSMATES. 



their shells by the action of the gastric juice, and there 

 issues an embryo singularly armed. As we have before 

 said, it carries in front two stylets in the axis of the 

 body, and on the right and left sides two other stylets 

 curved at the end, which act like fins. These embryos 

 bore into the tissues as the mole burrows into the soil. 

 The middle stylets are pushed forward like the snout of 

 the insectivore, and the two lateral stylets act like the 

 limbs, taking hold of the tissues and forcing the head 

 forwards. In this manner the embryos perforate the walls 

 of the digestive tube. 



An egg of the Tsenia solium may be swallowed by a 

 man instead of passing into the stomach of the pig. It 

 is hatched in his stomach precisely in the same manner, 

 and the embryo takes up its lodging in some enclosed 

 cavity. Some have been found in the eye-ball, in the 

 lobes of the brain, in the heart, or in the muscles. We 

 have lately read an account of the effects produced by 

 one of these wandering worms, on a man who died after 

 suffering from a peculiar disturbance of the mind. Two 

 spirits seemed to haunt and speak to him, the one a 

 German, the other a Pole. Filthy images were called 

 up before his imagination. At the post-mortem examina- 

 tion, cysticerci were found to occupy the sella turcica, 

 near the commissure of the optic nerves. One of these 

 was alive, the others were calcified. Two others in a 

 similar condition occupied a lobe of the brain. 



Man harbours not only the Tsenia solium, but 

 another species very similar, which naturalists have only 

 learned to distinguish from it during the last few years, 

 the Tsenia medio-canellata. We give a magnified repre- 

 sentation of the scolex, that is to say, of the head of this 



