344 PARASITES OF ANIMALS 



the infested earth, namely, two from the jar and one from the 

 closed phial, and made a microscopic examination of their 

 respective intestinal contents. In one of the worms from the 

 jar I found several embryos clearly referable to my strongyles, 

 their structure showing scarcely any advance upon that exhi- 

 bited by the embryos in the mould itself. The weather was 

 now excessively cold and the larvaB were motionless ; neverthe- 

 less, the application of warmth showed that they were by no 

 means dead. The faacal matter obtained from the worm that 

 had lived in the phial displayed an immense number of 

 infusoriae (Bacteria) which rushed about rapidly over the field of 

 the microscope. No other signs of life were detected. 



On the 2nd of November I found my solitary strongyle larva 

 alive, but its movements, though active, were by no means so 

 active as on the previous day. No fresh structural changes 

 had occurred. 



At noon on the 3rd the larva at first lay almost motionless 

 in the now thick and ropy saliva ; nevertheless, on applying a 

 thin glass cover its movements became tolerably vigorous. 

 During its quiescent state I succeeded in getting a good view 

 of the caudal rays and other imperfectly developed organs, of 

 which I retain figures. 



Having now satisfied myself that other new conditions were 

 necessary to enable the larva to arrive at sexual maturity, I 

 sought to transfer it to a glass tube filled with fresh saliva. This 

 transfer was a matter of difficulty. After passing the thick 

 ropy saliva into the tube, I examined the slide and found that 

 the larva was gone. I concluded it was in the tube, which, 

 in order to keep the contents warm, I subsequently carried 

 about concealed in my under-clothing during the day and placed 

 in my bed during the night. This increase of temperature, 

 however, caused decomposition of the saliva ; so when next day 

 I diligently sought for my experimental nematode it was no- 

 where to be found. Thus terminated my observations on the 

 first set of embryos, which had enjoyed their temporary sojourn 

 in the intestinal tract of the earth-worm, and which had certainly 

 afterwards undergone a series of marked structural and mor- 

 phological changes, accompanied with ecdysis. 



The weather had now been for several days exceedingly cold, 

 but on the 4th a favorable change set in, which led me to hope 

 that I might be able to verify the facts above recorded. 

 Accordingly, as a new point of departure, I re-examined the 



