OF PUS IN THE BLOOD. 
43 
the globules of pus undergo no change after having been long kept 
in water ; accordingly, if the suspected blood be mixed with this 
fluid, the blood-corpuscles will soon become invisible, and any 
globules of pus that may be present will subside to the bottom of 
the vessel, and may be easily seen, and their characters deter- 
mined, with a good microscope. Ammonia instantly renders the 
blood-corpuscle invisible, while that of pus is acted on but slowly 
by the alkali ; and the different action of acetic acid on pus and 
blood is equally remarkable. Hence I have employed these agents 
advantageously in conjunction with the other means; and I have 
also seen pus-globules in the blood, though rarely, without any 
preparation. With water, however, the examination is most easy, 
simple, and satisfactory, if the observer is thoroughly familiar 
with the microscopic characters of the fluids under examination. 
A good instrument, nevertheless, is necessary ; and the admirable 
deep object-glass of Mr. Ross is the one I have principally em- 
ployed. It is hardly necessary to add, that chyle-globules are not 
likely to be mistaken for those of pus, since, independently of other 
distinctions, the medium diameter of the latter is at least ^sV^th of 
an inch, which is above twice that of the former. 
Exp. 1. — A weak solution of corrosive sublimate was injected 
into the subcutaneous cellular tissue of a dog’s thigh : great swell- 
ing of the limb took place, and he died forty-five hours after 
the injury. A good deal of serum mixed with fibrine was found 
in the cellular tissue of the thigh, but there was no purulent de- 
posit. 
Several pus-globules were detected in some blood obtained from 
the right ventricle of this dog’s heart. 
Exp . 2. — A large dog had both his tibiae injured by some ope- 
rations connected with necrosis : great swelling of the limbs, with 
violent fever, succeeded, and he died forty-three hours subse- 
quently. 
A large quantity of fibrine was found diffused into the cellular 
tissue of the extremities, mixed, in one of them, with a very scanty 
proportion of purulent matter. 
In some blood, obtained from the vena cava, numerous globules 
of pus were observed. 
Exp. 3. — An irritating fluid was injected into the peritoneum of 
a dog : he had great thirst, refused food, and died on the third day 
after the operation. 
A large quantity of coagulated lymph and sanguinolent serum 
with some pus was found in the belly. 
In some blood obtained from the inferior cava vein many glo- 
bules of pus were seen. 
Exp. 4. — Two ounces of pus were injected into the left pleura 
