292 



PARASITIC DISEASES 



an appalling number of deaths from hydatid 

 disease; Leuckart, in 1863, said of it: — 



4 'At present, almost the sixth part of all the 

 inhabitants annually dying in Iceland fall victims 

 to the echinococcus epidemic." 



Before Klichenmeister s experiments in 1852, 

 there was no general knowledge of the exact patho- 

 logy of entozoic disease. The advance was not 

 made by the experimental method alone ; other 

 things helped : but among them were neither 

 clinical experience, nor what Sir Charles Bell called 

 "the observation of the just facts of anatomy and 

 of natural motions." 



Beside the entozoa, there are also vegetable 

 parasites. Of these, the most important is the 

 streptothrix actinomyces, the cause of actinomycosis 

 in man and cattle. Israel, in 1877, gave the first 

 accurate account of it in man ; and Bollinger, the 

 same year, studied it in cattle. Ponfick, in 1882, 

 recognised the identity of the disease in man and 

 animals. In 1885, Israel published the collected 

 records of 37 cases in man, tabulated according to 

 the site of the primary infection. Bostrom, about 

 this time, made cultures of the fungus : but all 

 the earlier attempts at inoculation failed ; and it 

 was not till 1891 that Wolff and Israel published 

 their successful inoculations, and thus completed 

 the evidence that actinomycosis is a parasitic 

 infection, a growth of vegetable threads and spores, 



