138 PROCEEDINGS OF THE ACADEMY OF [March^ 



in such a small shell. The disappointing factor is the sluggish 

 action of the larva. It is encased in a well-marked sheath and while 

 hatching has a languid swaying motion. When hatched its motion 

 is scarcely more than a quiver. By the time it has been hatched 

 an hour all motion has ceased. Beyond this stage we have seen no 

 development. In 10 to 14 days the worm grows paler, faintly 

 granular and disintegrates. 



Supposing that some agent was necessary to dissolve the sheath 

 and liberate the larva, weak solutions of HCL and sodium bicar- 

 bonate were applied, but to no avail. At the suggestion of Dr. Fox,, 

 an emulsion of parrots' proventricular mucosa was made and applied 

 to the embryos. There was no development at room or incubator 

 temperature. 



The ova in the preceding experiments came from proventricular 

 slime and had not received the action of the bird's intestinal canal. 

 As soon as a bird was found with great numbers of fecal ova, they were 

 washed out and the above experiments repeated in graded acids and 

 alkalis, diluted pigeon serum, and tap water at room temperature 

 and 41° C. The same results have been secured: they hatch best 

 in tap water and serum at room temperature. 



The most rapid hatching occurred in a corked vial of tap water 

 at room temperature in which a female had been placed to deposit 

 her eggs for subsequent experiments. Four days later she was found 

 ruptured, her egg tubes protruding and also ruptured. In them were 

 worms in all stages of hatching. 



Animal Experimentation. 

 Three modes of transmission would seem to be possible: 



1. Passage of egg into drinking water, and direct entrance of 

 the egg to the host, as in the case of the common pinworm, Oxyuris 

 vermicularis. This is the simplest possible cycle. 



2. Passage into drinking water, a hatching or perhaps a moult or 

 two, and then, by drinking or skin perforation, reinfestation, as 

 seen in the hook-worm, Necaior americana. 



3. Passage of eggs into water or soil, ingestion by an intermediate 

 host with moultings, passage from secondary host to water, and so 

 back to definitive host, as seen among the flukes, Faspiola hepaticum. 



A fourth mode, in which a biting insect might figure (as in filari- 

 asis) is surely ruled out, as no embryos have been found in either the 

 peripheral or deep bloods of our verminous birds upon repeated 

 examinations. 



