342 Dr Eschricht's Inquiries concerning 



CHAP. V. INTESTINAL WORMS ARE IN ALL CASES THE OFFSPRING 



OF OTHER INTESTINAL WORMS. 



Sect. 1. Helminthiasis is coyitagious. — It is evident enough 

 that the three principal arguments against equivocal gene- 

 ration, applicable likewise to the infusoria, are most power- 

 ful when brought to bear upon the Entozoa. Their limitation 

 to distinct species is too well ascertained, their anatomy too 

 complicated, and their fertility too striking, not to force the 

 conviction upon us, that intestinal worms are the offspring of 

 other similar worms, and may thus deposit young, not only in 

 any body which they may inhabit, but in other bodies also. If 

 this view be correct, the Entozoa will spread by a kind of emi- 

 gration, and Helminthiasis may often appear epidemic or con- 

 tagious: and yet these characteristics seem to have escaped the 

 notice both of the vulgar and of physicians; and this chief- 

 ly because both these classes confounded the Ascaris lumbri- 

 coides with the common earth-worm, and so had a ready 

 explanation of the almost constant occurrence of the com- 

 plaint among children, in the supposed fact of the worm be- 

 ing found in the soil, and being thence conveyed into the 

 w^ater used for drink and for all domestic purposes. At a later 

 period, when the science of Helminthology was more cultivat- 

 ed, so many difficulties simultaneously arose as to the mode in 

 which the Entozoa got into the body, that it came to be gene- 

 rally doubted if they were introduced into the body at all, and 

 to be extensively believed that their equivocal generation was 

 the only reasonable way of explaining their appearance. Hence, 

 all we can now do is, to examine facts and not theories, regard- 

 ing the mode in which Helminthiasis is spread and propa- 

 gated. 



The contagious nature of the complaint arising from the 

 presence of Ascarides lumbricoides is, I believe, evident from 

 the fact, that this worm not only appears in the human spe- 

 cies, but likewise in several animals, particularly domestic 

 ones, as the horse, ass, cow, hog, and also, it would seem, in 

 the dog and cat. This fact can never be ascribed to similarity 

 of diet or manner of life ; and the habitat of the parasite is 

 common to all these animals. The contagious character of 

 the Tcenia solium and the Bothriocephalus latus is perhaps Ktill 



