164 
Extracts from British and Foreign Journals. 
THE NATURE OE THE SALIVA IN THE HORSE AND DOG. 
Bv M. Claude Bernard. 
[The following lecture was selected by us for publication 
some time since; it has^ however, been unavoidably set aside 
to give place to subjects of more pressing interest.] 
Saliva is secreted by three principal glands, the functions 
of which require in each particular case a separate investiga¬ 
tion. Each of them has, in fact, its own peculiar use, and its 
action, when interrupted, cannot be supplied by that of its 
congeners. 
As in the case of each gland a definite surgical operation 
is required in order to obtain in a state of perfect purity the 
liquid which it produces, I believe it to be indispensable that 
the precise anatomical notions which will enable you to 
repeat the experiment for yourselves should be laid before 
you at once. 
The parotid gland in the horse is situated partly beneath, 
and partly before, the external ear. The numerous ducts 
\^'hich arise from its granulations gradually coalesce into a 
considerable trunk, which, after descending for a certain 
space, and then rising again towards the mouth, penetrates 
into the oral cavity in front of the second molar tooth. A 
curve is thereby described, the concavity of which embraces 
the ascending ramus of the lower jaw. The fascial vessels 
and nerve which pass over the duct must be carefully avoided 
in dividing it. In order not to injure these important parts, 
the anterior edge of the masseter must serve us as a guide in 
performing the operation. Let the incision be carried along 
its lower third, and the duct will be at once discovered, on 
the very point where it changes its direction and rises 
towards the mouth. It may there safely be divided so as to 
allow a slender tube to be introduced. The one we are about 
to make use of is a small silver pipe, containing a probe, 
which serves to clear it when obstructed, and makes it easier 
to be introduced. The excretory duct is then tied over the 
canula, just above the point where it has been introduced. 
(After demonstrating the operation on the head of a horse, 
M. Bernard performs the experiment on a living animal : not 
a single drop of saliva escapes at the moment when the tube 
is introduced into the ductus Stenonis.) 
