86 INDIRECT INJURIES CAUSED BY INSECTS. 
as it is, has had the sanction of grave authorities.1— The Gistri last men- 
tioned inhabit, in considerable numbers, two fleshy hags as big as a hen’s 
egg, and of a similar shape, near the root of the tongue. Reaumur took 
between sixty and seventy bots from one of them, and even then some 
had escaped. What other purpose these two remarkable purses are in- 
tended to answer, it is not easy to conjecture. He supposes that the 
parent fly must enter the nostrils of the deer, and pass down the air pas- 
sages to oviposit in them; but probably such a manceuvre is unnecessary, 
since there seems no reason, supposing the eggs to be laid in the nostrils, 
why the larva when hatched cannot itself make its way down to the above 
station, as easily as that of the sheep into the maxillary sinuses. Or, 
which perhaps is more likely, when the animal draws in the air, the eggs 
or larvae may be carried down with it, in both cases, to the place assigned 
to them by Providence.* 
No animal, however, is so cruelly tormented by Gistri as the rein-deer ; 
for besides one synonymous apparently with this of the deer (@. nasalis), 
_ from which they endeavour to relieve themselves by snorting and blow- 
| ing, they have a second which produces bots under their skin; not im- 
| probably the same species that in a similar way attacks the latter, as I 
“have stated above. We have heard that the vaccine disease is derived 
from the cow and the horse, and the small-pox is said to have originated 
in the heels of the camel ; but neither the ingenious Dr. Jenner nor any 
other writer on this subject has informed us that the rein-deer is subject 
to the distemper last named; yet Linné quotes the learned work of a 
Swedish physician on Syphilis, who gravely gives this as a fact!!* The 
inoculator, in truth, is the gad-fly, the tumours it causes are the pustules, 
and its larva are the pus. — It is astonishing how dreadfully these poor 
animals in hot weather are terrified and injured by them: ten of these 
flies will put a herd of five hundred into the greatest agitation. They can- 
not stand still a minute, no not a moment, without changing their posture, 
puffing and blowing, sneezing and snorting, stamping and tossing continu- 
ally ; every individual trembling and pushing its neighbour about. The 
ovipositor of this fly is similar to that of the ox-breese, consisting of 
several tubular joints which slip into each other ; and therefore Linné was 
probably mistaken in supposing that it lays its eggs'wpon the skin of the 
animal, and that the bot, when it appears, eats its way through it®: there 
can be little doubt (or else what is the use of such an apparatus ?) that it 
bores a hole in the skin and there deposits the eggs. About the beginning 
of July the rein-deer sheds its hair, which then stands erect — at this time 
the fly is always fluttering about it, and takes its opportunity to oviposit. 
The bots remain under the skin through the whole winter, and grow to the 
size of an acorn. Six or eight of these are often to be found in a single 
1 Reaum. v. 69. Dictionnaire de Trevoua, article Cerf. 
2 Vor the account of the Gstrus of the deer, see Reaum. vy. 67—77. 
5 Linn. Lach. Lapp. ii. 45. In the passage here referred to, Linné speaks of two 
species of Cistrus, though the mode of expression indicates that he considered them 
as the same. One was QZ. nasalis, from which they freed themselves by snorting, 
&c., the other @. Tarandi, which formed the pustutes in their backs. In Syst. 
Wat. 969. 3, he strangely observes under the former species, “ Habitat in equorum 
jauce, per nares intrans!” confounding probably QZ. veterinus of Mr. Clark with the 
true @. nasulis, 
4 Lach. Lapp. i. 280. 5 Flor. Lapp. 79 
