REPORTS OF CASES. 
791 
Thinking that they were mistaken I paid no heed to them. 
On the 6th of August, or about four months after I had first 
seen the animal, the owner brought him to be treated for an 
attack of eczema. 1 was asked if I knew him, and 1 answered 
that I did not. I was then informed that this was the dog 
that had had lockjaw, and could not possibly live a day or 
two at the longest. He was so fat that he could hardly run. 
ABSENCE OF THE LEFT CAROTID ARTERY. 
By Wm. H. P. Monk and G. W. Mead, Jr., Students at the A. V. C. 
As students in the dissecting-room of the American Vet¬ 
erinary College, we recently had an opportunity to dissect a 
curious development of the terminal branches of the common 
carotid arteries. 
On the right side the carotid, at its termination, bifurcated 
in two branches, one the external carotid, the other a special 
trunk measuring about three and one-half inches in length, 
and then dividing into two branches, one the occipital, the 
other the internal carotid. 
On the left side the occipital originated from the parent 
trunk, in common with the external carotid, but the internal 
carotid was missing entirely, and no trace of it could be found. 
On removing the brain with a portion of the spinal cord, 
the following condition is observed : The cerebro spinal of 
the right side is quite large, that of the left apparently smaller. 
Both give their branches to form the lozenge-shaped arrange¬ 
ment from which rise the median spinal and the basilar trunk. 
This trunk divides anteriorly into branches ; one that remains 
upon the median line, and running forward to the interpedun¬ 
cular fissure, divides into branches, which go to anastomose 
with the median cerebral. The other goes to anastomose with 
the internal carotid of that side (the right), representing evi¬ 
dently the posterior cerebral. 
The right internal carotid, after entering the cranial cavity, 
describes a double S and forms a single trunk, which, running 
from the right to the left, arrives at the median line back of 
the pituitary gland and there divides into two large branches, 
which pass on each side of the gland, run forward, each one 
forming the median and the posterior cerebral of both sides. 
On this surface of the brain there is no appearance of the 
left internal carotid. The entire circulation was furnished 
by the internal carotid of the right side. 
The subject was a small horse, some eight years old, in 
fair dissecting condition, and bearing no external indication of 
this curious abnormality. 
