256 T. L. BANCROFT, 
I was desirous of ascertaining, (although the chance of 
doing so was very slight), where in the dog’s body the 
young filarize lived before partaking themselves to the heart. 
I had on several occasions, whilst dissecting filariated dogs, 
found half grown forms in the lungs. One dog, which had 
been bitten by 103 filariated mosquitoes and in whose body 
there would be at least fifty worms, was examined three 
months afterwards; the tissues were sliced with a knife or 
cut into small pieces with scissors in hope that, were a 
worm cut, it might move or its body protrude and thus 
attract the eye; nothing however was seen. Mature filarize 
scarcely move when cut across, and might readily be over- 
looked, so it can be understood how such delicate bodies, 
as young filarize, might easily escape detection. It is 
probable that the young filariee live in minute arteries in 
the lung. Another filariated dog was examined seven 
months after infection, full grown filarize, both males and 
females—the females ten inches long, which is the maximum 
length they attain to—were found in the heart; the uterine 
tubes were devoid of embryos however. ‘The parasite is at 
this date, probably sexually mature, but a month or two 
must elapse before embryos are developed. 
Two dogs used as a “‘control”’ in this investigation, last- 
ing over a period Of two years, remain free from filarie. 
EXPLANATION OF DIAGRAMS, 
Fig. 1—Diagram of a ‘‘ House Mosquito,’’ Culex fatigans, 
Wied., in the act of imbibing blood, drawn from photo- 
micrographs. 
Fig. 2—Diagram of the head of a mosquito imbibing blood, 
depicting the escape of a young filaria into the skin 
along side the stylets. A, thorax; B, head; C, clypeus; 
D, skin; EH, eye; F, filaria; H, labelle; I, antenna; 
L, labium; N, neck; O, occiput; P, palpi; S, stylets. 
