255 
FARRTERY. 
colour; this, however, does not indicate any inflamma¬ 
tion, but (hews an incipient difeafe of the'cornea, which 
now receives more ferum into its velfels than they can 
make transparent, becaufs they are too much diltended 
and enlarged to produce that effeift ; jti(1 as any coloured 
fluid will not appear tranfparent, if contained in a glafs 
tube of an increafed diameter. Thefe circumftahces alfo 
apply to the difeafe when going off, as well as in its inci¬ 
pient date. But in a number of cafes, the inflammation 
is periodical, and blindnefs is fure to enfue, though not 
always in both eves; for when-one eye becomes blind, 
the other frequently remains well; and hence farriers have 
been in the habit of taking out one eye, to fave the other; 
a praftice often attended with fuccefs, becaufe the in¬ 
flammation that is thus produced a6ts in the fame way 
that a rowel or feton would do, in drawing the offending 
matter. 
The inofi general termination of fpecific ophthalmia, is 
in a cataract ; which is an opacity of the cryftalline lens, 
that was before tranfparent ; it generally becomes of a 
milky white, or a yellow colour inclining to white in the 
circumference ; fometimes the capfule of the lens becomes 
thickened, and even bony ; an example of which is (hewn 
in the mufeum of the veterinary college of London. At 
other times, the lens efcapes from its capfule, and adheres 
to the iris, which comes in contact with the cornea ; the 
vitreous humour is then abforbed, and the pofterior part 
of the eye filled with lymph ; the lize of the eye being 
diminifhed. But if there is no lymph thrown out, 
then the cavity of the vitreous humour remains, and a 
feptum is formed between it and the lens. When the 
tens or cryftalline humour thus detaches itfelf from its 
capfule, if it does not adhere to the iris, it rolls about 
the eye like a marble, and produces abforption of the vi¬ 
treous humour, retina, &c. See thefe parts delineated in 
the Farriery Plate VIII. fig. 4, 5, and 6. 
In the human fubjefh an operation is commonly per¬ 
formed for extrafling the cataract, which is generally fuc- 
cefsful in giving fight to the patient; but in the horfe it 
is ufelefs, and (hould never be recommended, becaufe the 
important functions of tlie- cryftalline lens require to be 
fupplied by two different forts of glaffes, convex to fee 
near objefts, and concave to fee diftant ones. Now it is 
utterly impofiible to employ thefe, fo as to be of advan- 
tage to the horfe ; and without them vifio.n is fo confuted 
for want of the lens, that it is much better to have the 
animal quite blind, fince he would be continually hum¬ 
bling and darting, and of courfe of little value to the 
owner. The only advantage of extracting a cataradl from 
the eye of a horfe, would be when the animal is turned 
into the field to graze. But befides the objection above 
mentioned, there are feveral more ; for the operation is 
very difficult to be performed, from the retradtor mufde 
drawing the globe into theoYbit, fo much that the opera¬ 
tor cannot eafily get at the cornea ; and befides, this part 
is naturally much lefs convex than the cornea of the hu¬ 
man fubjedt. 
Collection of Mattel. —This difeafe of the eye 
is formed by the iris, which gravitates to the depending 
part of the anterior chamber of the eye, and has a fcmi- 
circfila'r appearance, on account of the figure of the cornea; 
Jn this the pupil is always contracted. If it is not foon 
removed, by prefiing on the cornea and iris, it will pro¬ 
duce blindnefs ; therefore; as foon as the matter is form¬ 
ed, we ought to pundture the edge of the cornea with the 
point of a lancet, to allow the offending matter to efc-ape. 
It is generally a fign of fucceeding cataradt. 
Gutta Selena: —This is commonly called 'glitfs-eyesj 
by farriers, becaufe the eyes appear in this difeafe very 
clear and glafly. It is a much more frequent affedtion of 
the human eye, than of that of the horfe. The pupil is very 
much enlarged and dilated, in bonfequence of fympathiz- 
mg with the nerve, which is not, in this malady, capable 
of being Simulated by the rays of light. It generally 
arifes from a difeafed affedtion of the brain, as from farcy, 
or a fevere blow on the head. When proceeding from 
either of thefe two caufes, a cure may be performed, by 
bleeding, purging, bliftering the top of the head, and fti- 
nuilating the nuftrils with the vapour of vitriolic acid, or 
marine acid. 
Catalact, or Moon-Blindness. —In a courfe of 
experiments adopted by profelfor Coleman for the purpofe 
of reducing this difeafe, he began with bleeding from the 
jugular or angular veins, and at the fame time employed 
purgatives frequently repeated, as well as diuretics, alte¬ 
ratives, &c. After which he tried all the medicines of . 
Meffrs. Phipps and Wathen, but without any degree of 
permanent fuccefs. The local and furgical treatment was 
as follows : Firft, he ordered fcarifications ; and paffed a 
feton through the membrana conjundliva; but without 
effefl.—Secondly, be removed fome'of the larger veffels 
going to the cornea, and divided them with the adhial cau¬ 
tery, but without fuccefs.—Thirdly, he applied leeches 
to the conjunctiva; but with as little effedt. Laftly, he 
took up both the carotid arteries; which proved of no 
avail, from the anaftorr.ofis which the vertebral arteries 
form with them. Therefore the treatment is now con¬ 
fined entirely to bleeding and gentle purgatives; fomen¬ 
tations of warm water, in order to diminiftv the irritation 
from the tears that run over the cheeks; and plenty cf 
moderate and regular exercife to increafe the perfpiration. 
Watery Eyes. —This affedtion proceeds from an in- 
created fecretion of tears, which flow fpontaneoufly down 
the cheeks, in confequence of the lachrymal dudts not 
being capable of carrying the fuperfluous quantity away ; 
or elfe from an obflrudtion of the nafal dudt. The cure 
confifts in diminifhing the increafed fecretion of tears, by 
judicious bleeding and diuretics ; with proper exercife. 
But when the difeafe is found to proceed from an obftruc- 
tion of the dudtus ad nafurn, the paffage muft be opened 
by injecting a decodtion of linfeed, orany other lubricating 
liquid; if this fhould fail, the dudtus ad nafuin mult be 
opened with an inftrument, introduced with great dexte=- 
rity from the eye down to the nofe. 
Of BOTS and. WORMS. 
The bots have for ages been confidered as conftituting 
one of the mod injurious internal maladies with which 
the horfe can be afflicted. Naturalifts, however, will not 
admit that thefe infedts are prejudicial to any of the vifeera, 
inafmuch as they are appointed by the unerring wifdom 
of Providence, for the nidus of the cefirus cqui ; and with¬ 
out which, it feems apparent, that this fpecies of infect 
would foon become extindh After the egg has been 
licked in by the horfe, it is hatched in the ftomach, where 
the eruca is nourifhed till ripe for itspnpa date, and then 
it attaches itfelf by a kind of bolder or hook to the villous 
coat. When it has undergone this part of its metamor- 
phofis, it drops fpontaneouily from its hold, and is then 
caft out with the freces, to become a fly. This is the 
grub which crows fo anxioufiy fearch for in the dung of 
horfes. Thofe which efcape from being devoured foon 
caft oft" their (lough, rife upon wing, copulate, and depolit 
their eggs, like the parent, on thofe parts where inftindt 
diredts that they (hall be taken into the ftomach of the 
horfe. Hence it is manifeft that all horfes in their wild 
(late, as well as in the domefticated, when turned out to 
grafs, muff have been, and will be, forever (object, in 
the dimmer months, to the attacks of this fly,* for the- 
purpofe of propagating its fpecies ; that therefore, through 
the winter, the horfe will be afflicted with the bots ; but 
which, in the fpring, by an ordination of nature, are com¬ 
pletely voided, in order to alfume their perfect infect 
(tale. A clufter of thefe grubs, as taken by Lafolfe from 
the ftomach of a horfe that was killed in battle, is (hewn 
in the Farriery Plate X. fig. 3 ; 'but the ftomach did net 
3 appears 
