THE CULTIVATOR. 
285 
warm water, and the remains of the ointment washed 
off before the next milking.” 
We have spoken above, of bathing the bag with cold 
water to reduce the swelling, but if mercurial prepara¬ 
tions are applied, warm water must be used. 
THE SHEEP BOT —(QZstrus ovis .) 
The family of (Estrida is numerous. No less tnan 
three species are known to attack the horse; while the 
ox^ sheep, -goaf, deer, and even man, in some countries, 
are each annoyed by one or more kinds peculiar to them¬ 
selves. The habits of the different species are quite va¬ 
rious—some breeding in the skin of the animals which 
they attack, (as the 0. hovis , or ox-fly;) others breeding 
in the intestines, (as the O. equis, or horse-bot;) and 
others, like the species under consideration, passing the 
first stage of existence in the cavities of the head. 
The effects of the attacks of these insects on animals, 
have never probably been clearly ascertained. In respect 
to those which attack the horse and the sheep, in particular, 
there has been much diversity of opinion; some contend¬ 
ing that they are a great injury to the animals, some¬ 
times causing death; while others suppose they occasion 
but little inconvenience. 
Twelye or fifteen years ago, many sheep were lost in 
different parts of the country, as was then generally sup¬ 
posed, from worms in the head. Upon a particular 
examination, however, of some of the animals after death, 
the most indubitable evidence was fonnd of the disease 
called rot , and but little doubt remained that their death 
was attributable to this cause. We dissected the heado fa 
sheep which had died from our own flock, and found in 
the cavities no less than forty larvse of various sizes. Our 
neighbors said the death of the sheep had been undoubt¬ 
edly occasioned by the worms, and that others, then exhi¬ 
biting similar symptoms, would also die. But an examina¬ 
tion of the heart and liver of the subject alluded to, as 
well as many post mortem examinations of others, inva¬ 
riably resulted in discovering the most marked symptoms 
of the rot. We have also examined the heads of healthy 
sheep, which had been slaughtered, often finding the 
worms in considerable numbers. 
Still we are by no means prepared to say that the sheep 
is not injured by the insect; still less to admit the sug¬ 
gestion of Mr. Youatt, that “ these bots may be servicable, 
rather than injurious to the sheep.” We presume not to 
fathom the designs of Providence in the creation of this 
or other forms of animal life—that everything-, as Mr. 
Y. observes, tends to a benevolent end, we would by no 
means deny. We must confess, however, that in this 
ease, we are unable to discover how the attacks of the 
insect conduce to the health or comfort of the sheep. It 
is certain that the fly is much abhorred. Any one will 
assent to this, who has witnessed the conduct of a flock 
of sheep exposed to its attacks, and observed (heir saga¬ 
cious efforts to avoid the enemy. The poor animals 
may be seen huddled together upon some spot of bare, 
dusty ground, and will there endure for hours the scorch¬ 
ing heat of the sun. The group stand with their heads 
towards the centre and with their noses close to the 
earth. If a fly of this kind appears near, they strike vio¬ 
lently with their fore feet, and at (he same time plunge 
their noses in the thickest dust, which usually prevents 
the fly from reaching them. Sometimes the fly, darting 
out suddenly, will attack the sheep while quietly feeding, 
and succeed in leaving its egg in the nostril. In such 
case, the animal instantly exhibits the greatest uneasi¬ 
ness—shakes its head, stamps, and runs off furiously to 
some dusty spot, or protected corner. 
Soon after the egg is deposited, it is hatched, and the 
young larvse makes its way up the nasal sinuses to the 
cavities over the eye anti around the brain. The motion 
of the worm is obviously disagreeable to the sheep, as is 
shown by its restlessness, sneezing, &c.; but when it has 
reached its destined place, and remains nearly stationary, 
we have not been able to discover that it occasioned pain, 
or sensibly affected the health of the sheep. 
The attack of the fly continues from May to August, 
and the larvse from the eggs first deposited, reach their 
full size and are ready for transformation on the return of 
warm weather the next spring. The efforts of the full- 
grown worm to escape from the head, appear sometimes 
to create disquietude and pain. They work their way 
out of the head as they first ascended, and crawl into the 
ground or the rubbish of the sheep yard. Their skin 
gradually shrinks and hardens, and they are soon formed 
into the chrysalis. In from forty to sixty-three days, 
according to the experiments of Valisnieri, the perfect 
transformation takes place, and the fly comes out. The 
variation in the length of time the insect remains in 
the pupa state, is dependent on the temperature—matu¬ 
rity being hastened by warmth. Though most of the 
worms leave the head of the sheep to undergo transfor¬ 
mation, it is certain that all do not. We have sometimes 
found shells of the chrysalis in the sheep's head, showing 
that some reach the fly state before leaving. 
Not having had an opportunity of examining this fly with 
sufficient minuteness to give a particular description, we 
take that of Mr. Youatt, as follows:—“The fly is con¬ 
siderably smaller than the size of the larva would indi¬ 
cate. Its head and corslet taken together, are as long as 
the body; and that is composed of five rings, tiger-col¬ 
ored on the back, with some small points and larger 
patches of a deep brown color. The belly is of nearly 
the same color, but has only one large circular spot on the 
centre of each of the rings. The length of ihe wings is 
nearly equal to that of the body, which they almost en¬ 
tirely cover. They are prettily striped and marked. 
The eyes have the appearance of net-work, and are of a 
deep and changeable green color. They occupy less 
space upon the head than those of most flies. In the 
small space between them, are placed three other mi¬ 
nute eyes in the form of a triangle. They may be dis¬ 
covered in a tolerable light, or by a lens of small power. 
The rest of the head is yellow, and seemingly hollow. 
It appears as if it were perforated by a great number of 
small holes, like a piece of sponge, and at the bottom of 
each of these cavities, a small black spot appears.” 
The figures in the above cut are also taken from Mr. 
Youatt’s treatise. Fig. 1 shows the larva or the bot of 
the oestrus ovis, half grown; 2, the same at its full 
growth; 3, the oestrus ovis in the pupa state; 4, the 
oestrus in the perfect stale, giving a full length view 
of it. 
To prevent the attack of the oestrus, it has been 
recommened to smear the noses of sheep with tar. We 
are unable to speak from experience of the efficacy of 
this. It is claimed that the odor of the tar, deters the fly 
from alighting to deposit its egg. It is evident however, 
that to answer any purpose, it should be applied with 
such frequency as not to become much dried on the sheep. 
Scotch snuff is sometimes thrown up the nostrils of the 
sheep, as recommended by Mr. Jewett, page 58, of this 
volume of the Cultivator. The irritation produced by 
the snuffbrings on sneezing, by which it is thought the 
worm is ejected, and the head besides cleared of its un¬ 
healthy humors. 
Several years ago, we adopted the use of the trephine, 
to relieve the difficulty occasioned, (as we then thought,) 
by worms. By trepanning the skull a little above each 
eye, some of the worms were taken out, and by pour¬ 
ing oil into the cavities, it was supposed the remain¬ 
der would be destroyed. The operation being com¬ 
pleted, the skin was closed over the aperture made by 
the trephine, and the wound soon healed. It is not 
