NEMATODE HA MATOZOA IN THE DOG. 275 
innumerable ova may be made to pass into either channel, 
as the fluid is well charged with eggs in all stages of 
development. 
I have not, however, observed any free embryos in this 
fluid, nor could I find any along the whole course of the 
intestinal canal in the dogs examined, where the parasites 
were lodged in tumours in the cesophageal walls, although 
plenty of ova, apparently unaltered, could be detected 
throughout the entire gut.1| On one occasion only have I 
observed ova on a slide of blood containing hematozoa: this 
preparation was obtained by scraping the inner surface of 
the aorta with the edge of a covering glass. 
It would, therefore, appear that the ova require some 
considerable time before the escape of the embryo takes 
place, certainly a longer period than is sufficient for them to 
be conveyed the entire length of the intestinal canal. 
I have made numerous attempts at bringing the embryos 
to maturity: by means of moist earth; by feeding cock- 
roaches with bread soaked in fluid containg ova; by intro- 
ducing ova into the stomach and peritoneal cavity of frogs, 
&c., but have not yet succeeded—the ova and their contained 
embryos being, from a week to a fortnight afterwards, 
detected in the bodies of the animals without having under- 
gone any apparent change. 
Where the true habitat of these embryos may be is as yet 
unknown. Whether, after a lengthened sojourn in moist 
earth, or in water, or in the intestinal canal of some creature 
other than the dog, the embryo escapes and undergoes 
developmental changes, must be left for future inquiry, as 
must also the direct proof that the microscopic worms in the 
blood of the pariah dog are the brood of the Filarie sanguino- 
lente which may be lodged in the walls of the aorta or 
cesophagus, or in some other tissue, glandular or eonnective, 
about the base of the heart or elsewhere. All that I can say 
is that all my attempts at finding any other mature nematode 
in the vascular system of dogs affected with hematozoa have 
proved fruitless, and I have made careful examinations— 
macroscopic and microscopic— of every tissue and organ of 
the bodies of several animals, and followed the ramifications 
of the various arteries and veins in the trunk and in the 
extremities. On one occasion, no trace of any mature parasite 
in a hematozoa-affected dog could be found, but it is quite 
possible that the parent ma have escaped detection by being 
lodged in some out-of-t he-way tissue in the body, and one 
' Dochmius trichono cephalus is the ordinary nematode entozoon found in 
e intestines of dogs in India, 
