LARVA IN THE SKIN. 233 
which were upon the horse doubtless perished; but the dressing being 
washed off, the pests came again and again, being supplied by the source 
of all the mischief. 
Insects breathe through the skin. On that account, a hornet is more 
readily destroyed by dropping a little oil upon the exterior surface than 
by immersing the head in hydrocyanic acid. All, therefore, requisite 
for the removal of lice is smearing the entire body with any cheap oil 
or grease. But when the skin is washed, the business is not ended. 
Generally the horse troubled with lice is hide-bound, and may have 
various other affections derived from the debility which generated the 
parasites. 
LARVA IN THE SKIN. 
These annoyances are another result of turning an animal out to 
grass, the fly whence the trouble is derived never entering the stable. 
The insect rejoices in the freedom of the field; and man, by turning out 
his horse, finds the creature a fitting spot for the deposit of its eggs. 
This body is carefully deposited upon the back or sides. The warmth 
6° 
a. The winter residence of the larva. 
b. The summer abode of the insect. 
c. A drop of tallow falling upon the center of the 
abscess. 
of the animal hatches the larva; no sooner is it endowed with life, than, 
with the instinct of its kind, it burrows into the skin. The integument 
of the horse, however thick it may appear, is soon pierced by the active 
little maggot, which, thus snugly housed, retains its lodging until the 
following spring. During the winter, a small lump denotes its abiding 
place; but as the second summer progresses, a tolerably large abscess 
is instituted. 
The interior of the abscess, of course, contains pus. Upon that 
1. The spot through which the larva breathes. 
2. The insect, full size. 
3. The mouth of the parasite. 
4, The pus surrounding the body, and upon which 
the creature lives. 
5. The sac of the abscess. 
6. The fat of the horse, or the adipose tissue much 
swollen and inflamed. 
7. The skin. 
8. The superficial muscle. 
9, The muscle proper to the body of the animal. 
DIAGRAM OF THE LARVA ABSCESS, DIVIDED 
THROUGH ITS CENTER. 
secretion the insect lives and thrives. The inhabitant of a warm abode, 
and surrounded by its food, the early period of life no doubt is, for an 
