160 
J. HUILSON. 
in the blood, upon the end of the thrombus, layer after layer. 
The thrombus is prolonged beyond the mouth of the branch 
into the trunk, in the direction of the current of the blood, 
( 
and shoots out in the form of a thick cylinder, farther and 
farther, becoming continually larger and larger. It is these 
prolonged plugs that constitute the source of real danger, as the 
' stream of blood may detach minute portions, hurry them 
away with it, and wedge them tightly into the nearest system 
ol arteries or capillaries. Thus many cases of sudden death, 
that would be otherwise unexplainable, are accounted for. 
Now regarding the symptoms. These in thrombi of in¬ 
ternal blood-vessels, in many cases, would be impossible to 
recognize during life. We may have a suspicion of the 
trouble, but not sufficient to give a positive diagnosis. Per¬ 
haps externally, from the decreased amount of blood supplied 
to the part, we may detect more or less atrophy of the muscles 
supplied by such vessels. Thrombosis ol the iliac arteries, 
the vessel supplying the circulation of the posterior extremi¬ 
ties, may very plainly be recognized, both by symptoms plain 
to the sight, and by examination internally. I will endeavor 
to present these symptoms, as shown when affecting these 
vessels, in speaking of thrombosis. We understand, of course, 
that the blood-vessel is not entirely plugged by the clot, the 
blood being able to trickle in most cases between the coagu- 
lum and the coat of the vessel ; and, again, if both sides are 
affected, the symptoms would be shown in both extremities. 
The history of these cases will sum up about as follows : 
An animal, apparently sound in every respect, when driven 
for a short distance, develops symptoms of lameness, a weak¬ 
ness or slight paralysis behind, which will increase until un¬ 
able to make further progress. During this time he will break 
out in profuse perspiration over his body, the leg is kept in 
constant motion, alternately raised and lowered, in a spasmodic 
manner. Respiration is hurried, pulse very weak, and seems 
in great pain. Another marked symptom, also, is on feeling 
the leg below the hock we find it to be of an icy coldness. If 
you continue to urge him he may fall down. After resting 
or lying a certain length of time, he will get up, and when 
