NEMATODA, THREAD-WORMS 553 



perhaps in the majority, there are apparently no symptoms. Only when a 

 massive collection becomes lodged in the cecum or in the colon, local difficulty 

 may result from the irritation which the worms produce by boring their way 

 deep into the mucous membrane. Moosbrugger, Burchard, Federolf have seen 

 severe symptoms due to trichocephales : Extreme anemia, enteritis with pro- 

 fuse hemorrhagic stools, emaciation and loss of strength. Since Askanazy has 

 shown that the trichocephalus invariably has an iron-containing pigment in 

 its intestinal epithelium, the origin of which is the hemoglobin of the blood, 

 this form of helminthiasis will evoke much greater interest. 



The diagnosis may readily be made by the microscopic demonstration of the 

 characteristic ova, thick-shelled brown eggs, at both poles of which there is a 

 knob-like elevation. 



The trichocephales cannot readily be expelled, but the combined adminis- 

 tration of anthelmintics and purgatives will give the best results. Besides 

 santonin, we have employed successfully the ethereal extract of male fern. 

 From the basis of his experience, Lutz advises thymol. 



Among the nematodes which are of great pathogenic importance belong 

 the trichina spiralis, Owen, 1835, and the anchylostoma duodenale, Dubini. 

 1843. I shall first describe 



Trichina spiralis, 



the appearance of which in the musculature of man was observed by Peacock 

 in 1828, and by J. Hilton in 1833. These and other findings, which were 

 looked upon only as interesting secondary findings at autopsies, attained their 

 true importance in 1860 through v. Zenker. In a case observed by this author, 

 of a girl who was dying from symptoms resembling enteric fever, numerous 

 recently entered trichinae were found in the muscles, as well as many in the 

 intestine, while no other possible cause for her disease was evident. The same 

 author ascertained that in the district in which the patient had lived a num- 

 ber of milder affections had occurred. Sausages and hams which were still 

 there permitted the detection of massive encapsulated trichina. From this 

 time, the attention of physicians was directed to trichiniasis. It was soon pos- 

 sible, even during the life of the patient, to demonstrate the cause of the 

 disease in the musculature. Abundant material was furnished by the " tri- 

 china epidemics " which appeared, particularly in Middle Germany ; and the 

 study of these rapidly added to our knowledge of the previously absolutely 

 unknown disease, both clinically and pathologically, and enabled us to reach 

 definite conclusions. 



But not only in Germany was trichinosis observed ; its existence was soon 

 demonstrated in Switzerland, England, Denmark, Sweden, Eussia, France, 

 Italy, India, Syria, America and Australia. Wherever the cause could be ascer- 

 tained, a connection with the ingestion of pork containing trichina was proven. 

 With the determination of this fact the question arose as to the source of 

 trichina for the swine. The theory that pigs were infected by the ingestion 

 of rain-worms, frogs and moles containing trichina; was soon shown to be 

 erroneous. Leuckart's view, promulgated in 1862, that rats were the actual 

 source of infection for the pig was of far-reaching importance. We are also 



