INJECTING PUS INTO THE VEINS OF ANIMALS. Ill 
blood poured out; and, on continuing the division of the 
veins upwards, the blood was still found to be fluid, with the 
exception of two or three small coagula, which were found 
about the middle of the cava. The right auricle contained a 
thin black coagulum, and small fibrinous coagula were scat- 
tered over and between the columnae carneae of the right 
ventricle, which contained a minute yellowish-looking matter, 
closely resembling the pus which had been injected.” 
A third case, in which the injection of a putrid fluid pro- 
duced analogous symptoms, is detailed at length in the 
* Medical Times’ of the 3d instant. 
What is it, 1 again ask, that produces the sudden and 
alarming symptoms in such cases ? There is no animal 
poison known which is so sudden in its operation ; and that 
pus, simply as such, produces no such symptoms, we have 
abundant proof from those cases in w T hich it has passed with- 
out obstruction in the course of the circulation. 
In a Report of a Committee of the Edinburgh Physiological 
Society of the 9th of January, 1853, upon some experiments 
undertaken at the instigation of Professor Bennett, it is 
stated, that fresh and healthy pus was slowly injected towards 
the heart into the jugular vein of a donkey. A slight 
obstruction was at first perceived, and the vein above the 
ligature could be seen to be somewhat swollen. This 
swelling, on being felt, was very soft, and, on pressing the 
vein from below upward, the mixed blood and pus was readily 
pushed before the finger. When all obstruction to the 
passage of pus from the syringe was removed, the syringe 
was again filled, and another ounce of pus was injected, 
without occasioning any further local effects. The animal 
was then allowed to get up, and exhibited no change in its 
normal condition whatever. The same ass was the subject 
of a second experiment a fortnight later, having been perfectly 
well in the interval. Six inches of the jugular vein were now 
exposed, and an ounce of perfectly healthy pus was then 
slowly injected downwards towards the heart. Another 
syringefull of pus was then injected. The animal presented 
no unusual symptom whatever during the next four days. 
To what, then, are to be attributed the sudden and fatal 
effects observed in Mr. Gamgee’s and in Dr. Mackenzie’s 
cases? I answer, to the coagulation of the blood in the 
heart. It is to this that are to be ascribed the sudden and 
fatal results in the cases which these gentlemen have re- 
corded; and to the absence of any such result, that the 
corresponding absence of symptoms must be assigned in the 
last-mentioned experiments. 
