Account of a Filaria in a Horse’s Eye. 295 
ova are thus introduced into the blood, carried to every part, and 
there only hatched, where they meet with a suitable nidus or 
pabulum, and other circumstances are favorable to their develop- 
ment.* Thus are they transmitted from parent to offspring, and 
thus do we account for the fact that each species of animal has 
its own parasites. In this manner the ovumof the FYlaria was 
deposited in the eye of the horse now exhibiting in this city, 
there hatched into existence, and where it may now be seen, 
reveling in an element which appears, so far as we can judge, to 
be highly congenial to its natare and habits. 
New York, June 24, 1840. 
Postscript. July 22, 1840.—Since writing the above I have 
seen numerous Filaria in eels and black-fish, chiefly on each side of 
the spine ; and the fishmen inform me that they have seen them 
in the eyes of fishes. Mr. A. Halsey also stated at the meeting 
of the Lyceum, after the above paper was read, that he had often 
seen Filaria in coleopterous and other insects. I have ascertained 
that they are extremely tenacious of life, and will not only bear 
Sreezing, but a temperature little inferior to that of boiling water, 
without depriving them of life. Professor Owen of London, the 
celebrated comparative anatomist, estimates the number of ova 
in one Ascaris lumbricoides which he examined, at 64,000,000. 
(Lancet, June.) The fecundity of the Filaria is probably not 
inferior. 
a very, curious disease of the =e has ina few instances been observed. The 
as injection of the conjunctiva, dimness 
of the weeping and swelling « ‘of the cornea. These are properly attended 
to, but the idthanaaod increases ; and on very close examination, a white 
worm, about the size of a hair and an inch in length, is found swimming in the 
aqueous humor, or that fluid weet is immediately behind the cornea. Now it is 
at once evident that the only way to get rid of or to destroy t cand is to pune- 
ture the cornea and let it out; and thie method has been ernie te In m some 
cases, however, not many days pass before another worm m 
and the operation is to be performed a second time, and the horse eventually Seti 
that eye. A veterinary surgeon, M. Chaigraud, who seems to have had most ex- 
perience about this, says that three or four days before the appearance of the 
worms, one or two minute bodies, of a reddish white color, are scen at the botiom of 
the anterior chamber of the eye. He also says, | as roa —_ ne about June, 
and is not seen after December. There is no animalcules get- 
ting into the eye, for there are undisputed instances of their ‘passing through the 
smallest capillaries, and being found in almost every tissue.” — Youatt on Cattle, 
p- 293. 
ib 
