150 
A. LIAUTARD. 
the greater weight of the cartilage of the concha necessitate a 
great force in the motor muscles of the organ. 
The ear of the ox, more widely open than that of the horse, 
is depending outwards, its forward and backward motions being spe¬ 
cially very developed. 
The ear of the cat , conical, ordinarily erected, pointed, has an 
opening turned forward ; its motion outward is always limited. 
In the dog is found a great variation, according to different 
breeds—something erected and short, more or less, it may be 
long and hanging and covered with more or less long and silky 
hairs. It is customary to cut a portion of the concha in some 
breeds, the hemorrhage accompanying the operation being of no 
consequence. 
The pig's ear varies much with the breed; it may be short, 
erected and pointed, or long and hanging, flattened and folded as 
in some dogs. 
That of the sheep and goat has the external characters of that 
of the horse, with the inclined direction of that of the ox. In the 
breeds where the horns have a spiroid direction, as in the merinos, 
it makes its exit through the center of spire. 
The little importance offered in the surgical point of view, in 
animals, by the middle and internal ear, induce us to pass them 
over without mentioning them. Rarely is there any occasion to 
observe diseases of the organs situated as deeply, and should a 
diagnosis be made of an affection of the internal ear, the propriety 
of an operation on it would scarcely occur to the surgeon. 
In few cases, specially in dogs, diseases of the middle ear, and 
specially the perforation of the membrana tympani have been 
noticed. 
The middle ear of the horse is remarkable bv its communica- 
«y 
tion with the guttural pouches already described. 
I do not know if difficulty of hearing in cases of purulent col¬ 
lections of this pouch have been noticed. However these troubles 
may exist, as the guttural pouch communicates through the Eus¬ 
tachian tube with the box of the tympanum. 
The physiological function of the guttural pouch is not well 
known. Is it in relation with the function of audition ? Has it 
