PARASITES OP ANIMALS. 125 



size. It is probable that such eggs, containing embryos, 

 when swallowed in the water that we drink, will be hatched 

 in our stomachs by the action of the gastric juice, and that 

 the young worms thus reach their destined abode. It is 

 possible, however, that under the proper circumstances the 

 eggs will hatch in the water, and that the free swimming em- 

 bryos may be swallowed in the same way. This part of their 

 history still remains uncertain. 



Symptoms. 



The presence of one or two of these parasites in the human 

 intestine does not ordinarily cause any marked effects or 

 noticeable symptoms. But when they occur in persons of 

 delicate health, and when in great numbers, as sometimes 

 happens, they may cause great disturbance of the natural 

 functions of the digestive system, and induce various serious 

 consequences. Cases have occurred in which from 100 to 

 500 of these worms have passed from one child. They live 

 chiefly in the small intestine, but sometimes enter the stomach 

 and may even be expelled by vomiting. In some instances 

 they have been known to perforate the walls of the intestine 

 and enter the abdominal cavity, and thus even to get into the 

 other organs, including the lungs, pleura, gall-bladder, etc. 

 In such cases death often results. 



Their presence in the stomach and intestine causes colic 

 and shooting pains, often accompanied by nausea, vomiting, 

 dyspepsia, itching of the nose, and diarrhoea. Owing to the 

 irritation of the nervous system they may cause restlessness, 

 convulsive twitchings, especially during sleep, and various 

 mental disturbances. In some cases, serious convulsions, 

 epilepsy, and insanity have been caused by them, and have 

 been cured at once by expulsion of the worms. 



Remedies. 

 The most reliable remedy appears to be santonine, but this 

 is a powerful preparation, and must be used with caution. 

 For children the dose is one to three grains, in the form of 

 powder, which does best if taken in castor- oil or honey, 

 though it may be sprinkled over a piece of bread and butter. 



