67 



is also further indicated by the well-known fact, that in India, where 

 it is the custom for the natives to carry water in skins on their backs, 

 the worm makes its appearance on the back and shoulders and upper 

 part of the body. The observation that very little intercourse with 

 the land is necessary for the conveyance of the worm, is strengthened 

 by the statement made by Rudolphi, that it occurs in persons who 

 have neither eaten nor drank in the countries where it is endemic, but 

 who yet become contaminated with the seminia afterwards to be de- 

 veloped. 



The entrance of the worm into the body is apparently unattended 

 with any observable symptom, and the person affected is unconscious 

 of its presence until the period when it is ready to make its exit. 



The life of the worm as a parasite may be divided into two periods. 

 And its existence as a whole, or until, as I suppose, its cycle of de- 

 velopment is completed, presents at least three, and it may be, four 

 periods or phases. 



In one of these periods the worm is latent, and in the other its ex- 

 istence is manifested by external symptoms. 



The former or latent period lasts, as I deduce from several cases in 

 which I have had the opportunity of inquiring carefully into all par- 

 ticulars, from twelve to eighteen months, seldom less or more. Dur- 

 ing this period the worm resides in the cellular tissue, and probably 

 usually at some depth from the surface, but this of course varies ac- 

 cording to the part invaded. In the instance of which the prepara- 

 tion is now before you, the parasite, as you will perceive, occupies 

 the cellular tissue immediately around the tendo Achillis and the 

 lower part of the muscles of the calf of the leg. It was discovered 

 accidentally in dissecting the leg of a negro youth from the coast ol 

 Africa, during whose life there were no indications of the worm's 

 existence. It is to be remarked, consequently, that during the latent 

 period the animal does not appear to exert any irritating influence 

 upon the surrounding tissues. No mark of inflammatory or other 

 morbid action was observable in the cellular tissue in which the 

 worm is lodged, in the present instance. 



Assuming the longer of the above-mentioned periods as the term 

 of the animal's latency, it would follow that its growth is very rapid ; 

 for I have, in every instance that has come under my notice, found 

 that the length of the worm has nearly reached, and in some in- 

 stances has exceeded, six feet. This would give a growth of about 

 an inch a week as its rate of increase. When the period of ripening, 

 as it may be termed, has arrived, the worm makes its presence and 



