386 
FISTULOUS PAROTID DUCT. 
actual condition of the parts. Should it arise from local abscess, 
it will present In exulceration more or less deep and irregular; 
on the other hand, should it be the effect of a punctured wound, 
it will appear a smooth, clear, circular aperture. If in the duct, 
as it ascends upon the side of the cheek, the aperture becomes so 
contracted that even in some cases a pin can hardly be introduced 
into it: if in a dependent situation, opposite to the angle of the 
jaw, it presei'ves a larger calibre. At first the aperture will be 
ulcerous and irregular, it then grows circular and smooth, and at 
length its edges obtain ar covering from an inversion of the skin—a 
cuticular border, which gives it the appearance of a natural outlet: 
in time, this border thickens, and grows hard and callous. From 
inflammation the border will become red and tumid; othewise it 
rises but little beyond the level of the surrounding skin. 
The discharge of saliva from the fistula is neither constant nor 
uniform. Commonly, the secretion accumulates in the duct, and 
suddenly bursts forth from the fistulous orifice, in consequence 
of the motion of the jaws. These emissions are observable during 
mastication; and are more particularly remarkable at the time 
the horse makes his first meal in the morning, after a long inter¬ 
val of maxillary inactivity. At first the fluid is poured out in a 
full stream, so that I have collected between two and-three drams 
of saliva per minute: after a time, however, the stream degene¬ 
rates into droppings, until at length the discharge ceases altoge¬ 
ther. But^ let me add here, all that I have said about the dis¬ 
charge of the fluid will be greatly influenced by the situation of 
the fistulous aperture: whether it is in the duct or in the gland, 
or be dependent or not. 
Concerning the fluid itself, what I have collected in these cases 
has been aqueous, limpid, saline ; in fact, has in general appear¬ 
ance resembled common water, possessing the ordinary properties 
of saliva. I can easily imagine, however, that in certain cases it 
undergoes alteration or decomposition, and gives rise, as Hurtrel 
d'Arboval tells us it does, to a \iscous and slightly purulent 
discharge, having a strong, penetrating, infected odour.’’ 
What changes the gland may undergo, or whether it undei^oes 
any organic alteration, in these cases, I am not prepared to an¬ 
swer : all that I can advance on this point from my own expe¬ 
rience is, that whenever any obstruction has been long in force 
to the flow of'the saliva, the gland becomes exceedingly tumid 
and tender on pressure, resuming however its natural appearance 
as soon as it becomes relieved from the distension. Not so, how¬ 
ever, with the duct: the main conduit, and even its ramifications 
within the substance of the gland, invariably become greatly dis¬ 
tended in their calibre when they have been subjected to excessive 
