282 FUNCTIONS OF THE GUTTURAL POUCHES. 
meatus auditorius externus ? (according to Lavocat, Guril, 
Lugh, Graf, &c.) 
2. Do they serve the purpose of phonation by perfecting 
the winnowing after the manner of the lateral ventricles ol 
the larynx? (according to Giraud, Mangolio, Lavocat, &c.) 
3. Have they uses as yet undiscovered connected with 
respiration? — uses, the end of which we suppose to be to 
impress upon the air, with which they are always filled, and 
which they alternately dislodge — some fresh modification? 
(according to my master, Professor Patillani, whose memoir 
I shall never forget.) 
4. Do we think that, by their situation, they may serve 
to cause a deviation and diminution of the force of the aerial 
column requisite to horses in rapid courses, or to break too 
violent shocks of it, at the time, against the bronchial tubes 
and walls of the pulmonary cells? (according to Professor 
Bossi.) 
5 . Or do they regulate the admission of air into the 
thorax, almost instantaneously change the temperature of it, 
break its first rush, moderate its violence, and modify its 
crudity, and so temper and make respirable the air entering 
the lungs? (Daniele Bertucchi.) 
After having shown the differences existing between the 
guttural pouches in the ass and mule, differences which are 
next to none, or very high when compared with those of the 
horse, M. Perosino entertained serious doubts on the in- 
fluence these organs exercise, either directly or indirectly, 
with the function of winnowing. He relates numerous and 
varied experiments, from which it evidently results that these 
pouches become dilated during expiration, but return to 
their normal dimensions during inspiration, contrary to 
what is generally represented. He also asserts, that in the 
many horses he has suffocated by hermetically closing their 
nostrils, he has uniformly found the guttural pouches enor- 
mously distended with air. From these facts, and a simple 
experiment he has made by the introduction into the cavity 
of a glass tube with alcohol in it, he has come to the con- 
clusion that, so far from the pouches having anything to do 
with inspiration, their function is intimately connected with 
expiration ; and he compares them with the vast and volu- 
minous receptacle communicating with the trachea in the 
cassowary of New Holland, and better still with the mem- 
branous sac of the antilope, particularly that of the reindeer, 
which is situated between the epiglottis and the thyroid 
cartilage, and destined, according to Carus, to satisfy the 
craving demands of respiration exhibited by these animals in 
