LIFE HISTORY OF ASCARIS LUMBRICOIDES. 31 
A python that died at the National Zoological Park, Washington, 
D. C., was infested with a species of parasite corresponding to de- 
scriptions of Ascaris anoura. This nematode apparently passes 
through the lungs in its life cycle, inasmuch as in addition to 28 
adult worms 115 to 160 mm. long, in the intestine of the python 
referred to, there were found in the lungs 65 young worms re- 
sembling in their structural details the adults from the intes- 
tine. These young worms varied in length from 18 to 38 mm., and 
if of the same species as the intestinal worms, as they appeared to be, 
it is evident that the larvee of this species can develop much further 
in the lungs than the larve of Ascaris lumbricoides. aia 
Considering the migration of the larve of Ascaris and other in- 
testinal nematodes through the lungs, it might be argued from an 
evolutionary standpoint that parasitism of the lungs by nematodes 
18 &@ more primitive condition than parasitism of the alimentary 
tract, and that only as the worms acquired a complete immunity to 
the effects of the digestive juices of the host did they move on into 
the stomach or intestines. 
DETAILS OF EXPERIMENTS WITH ASCARIS. 
The pale records of the writers’ experiments do not cover 
all the experiments that were made. A considerable number are 
omitted, as they add little to what is shown by those selected, so 
far as concerns the infection of experiment animals and the mi- 
grations of the larve in the body of the host. Numerous experi- 
ments have also been made relating to the hatching of Ascaris eggs 
in vitro, action of chemical reagents on the eggs, incubation of the 
eggs, etc., but the details of these experiments will not be given in 
the present bulletin. 
Experiment No. 1. 
January 15, 1917: Seven white mice fed with bread liberally soaked with a 
culture of eggs of Ascaris suum. 
January 19, 1917: Second feeding. 
January 24, 1917: Third feeding. 
January 27, 1917: Killed two of the mice, 12 days after the first feeding, 8 
days after the second, 3 days after the third. Post-mortem examination showed 
in one of the mice 21 larve in one-half of the lungs, 1 larva in the small in- 
testine, and 1 larva in the liver. In the other, 56 larve in one-half of the 
lungs, 1 larva in the esophagus, 2 larve in the trachea, and none in the small 
intestine. 
February 3, 1917: Two mice died, 19 days after the first feeding, 15 days 
after the second, 10 days after the third. One was examined and 1 larva found 
in the small intestine. The other mouse was not examined. Three of the 
mice originally included in this experiment either escaped from the cage or 
died and were destroyed without post-mortem examination. The feces re- 
maining in the cage at the close of the experiment were examined for larvse 
but none were found, 
