550 THE ANIMAL PARASITES OF MAN 



and are later found rolled up in the bed, or they are voided with the fecal 

 masses. In other cases they enter the stomach, thence the esophagus, and find 

 their exit by means of the mouth and nose. If they effect an entrance into 

 the larynx, severe suffocative phenomena are produced which may cause death. 

 Not rarely they find ingress to the excretory ducts of the large abdominal 

 glands, particularly the common gall duct, and thence reach the gall-bladder 

 or the liver and here produce serious lesions. More rarely they invade the 

 pancreatic duct or the vermiform appendix. The tendency of ascarides to 

 lodge in preformed foramina explains their occurrence in the abdominal cavity 

 after perforation of the intestine. If nematodes are capable of thus penetrat- 

 ing into intra- or extra-peritoneal abscesses, in their further course they may 

 be found in very remote situations. Thus, nematodes have been discharged 

 from the bladder, from the uterus, and from abscesses of the abdominal cavity. 



If there is a suspicion of helminthiasis, the microscopical investigation of 

 the feces and the finding of the characteristic ova will, as a rule, enable us io 

 make a positive diagnosis. 



The prognosis is generally favorable ; only exceptionally, by the wandering 

 of the parasites, are threatening symptoms produced. 



The administration of santonin will generally lead to the expulsion of the 

 parasite. This drug should never be given upon an empty stomach, however, 

 as rapid absorption permits its toxic properties to appear before its anthel- 

 mintic. As is well known, the symptoms of santonin poisoning consist of 

 yellow sight, yellow discoloration of the urine, general malaise, vomiting and 

 spasms, which may readily become dangerous in delicate children. Laxatives 

 soon cause the discharge of the poison. 



Santonin is given to children in doses of 0.025-0.05, to adults in doses 

 of 0.1. Lozenges which usually contain 0.025-0.05 of santonin may be ob- 

 tained in pharmacies, and one of these should be taken two or three times 

 daily. Upon the third day a laxative is administered, and frequently the 

 worms, which have been only stupefied, are discharged. 



The oxyuris vermicularis, Linne, 1767, is also a parasite that is well known. 

 The direct development of the oxyuris without intermediary host, which was 

 indicated by the investigations of Leuckart, is generally accepted. By the 

 swallowing of oxyuric ova, Leuckart, Grassi and others have directly infected 

 themselves. 



It does not appear to me to be sufficiently recognized that the ova are not 

 deposited in the intestine of man, but that the mature females leave the intes- 

 tine independently or with the feces. We can never conclude from the absence 

 of oxyuris ova in the feces that this parasite is not present in the intestine. Only 

 outside of the intestinal canal does the female discharge its ova in the fecal 

 masses. Frequently the surroundings of the anus are thickly covered with oxy- 

 uris ova which have been deposited there by female parasites which have been in- 

 dependently discharged. In the ova an embryo soon develops which, however, 

 does not extrude from its sac until after retransportation to the human intes- 

 tmal tract. Unpared fruit, fresh vegetables, berries and other fruits which 

 have come into the slightest contact with infected feces often bring about this 

 infection. In other cases transmission is brought about by clothing which is 



