CYSTICERCUS CELLULOSE 251 



allowed to run at will over the pastures, dropping the egg-laden 

 proglottids with the faeces in places where the water or food of 

 the stock may be infected. Dogs are allowed the free run of 

 the houses, are given unbounded liberty in playing with children, 

 and not infrequently eat from the same dish as their human 

 companions. The resulting prevalence of Echinococcus in both 

 dogs, stock and man is hardly to be wondered at. 



The precautions which should be taken to prevent the spread 

 and to bring about the control of this disease may be summar- 

 ized as follows: (1) avoidance of too great familiarity with 

 dogs, (2) exclusion of dogs from shores of lakes or reservoirs from 

 which drinking water is taken, (3) extreme cleanliness in handling 

 of food, (4) prevention of dogs from eating the entrails or meat 

 scraps of animals which may be infected with hydatids. 



Cysticercus of Taenia solium. The fact that the bladder- 

 worms of the pork tapeworm, Tcenia solium, sometimes occur in 

 man has already been mentioned. Since self-infection with the 

 eggs of the worm is a dangerous possibility, the presence of a 

 pork tapeworm in the intestine is to be looked upon much more 

 seriously than infection with other tapeworms. 



The bladderworms, technically named Cysticercus cellulosce 

 (Fig. 86 A), develop from the six-hooked embryos which are 

 freed from 1>he enclosing egg-shell by the gastric juices. The 

 embryos bore through the intestinal wall and migrate to various 

 organs and tissues to develop. 



The effect of Cysticercus infection depends entirely upon the 

 number present and upon their location in the body. A few of 

 them in the muscles or in the connective tissue under the skin are 

 quite harmless. In the eye, heart, spinal cord, brain or other 

 delicate organs their presence may be very serious, the symptoms 

 being due chiefly to mechanical injury. Infection of the brain 

 is usually accompanied by epileptic fits, convulsions and other 

 nervous disorders. There is no treatment except a surgical 

 operation, and this is often obviously impossible, both on account 

 of the number and position of the parasites. Moreover, in a 

 great many cases a correct diagnosis of this infection is made only 

 in a post-mortem examination. 



Sparganum. The group name Sparganum has been given to 

 plerocercoid larvae of tapeworms of the family Dibothriocepha- 

 lidse, of which the adult form is unknown and the true genus there- 

 fore indeterminable. 



