The blood in each of them was successively agitated till it began to coagulate; and making allowances for the different periods of agitation, there was no marked difference in the times of coagulation.
The color of the coagulum in every part of the cylinder, containing nitrogene, was the same very dark red. When it was agitated so as to tinge the sides of the jar, it appeared exactly of the color of venous blood received between two surfaces of glass; no perceptible absorption of the gas had taken place.
The blood in nitrous gas was dark, and much more purple on the top than that in nitrogene. When agitated so as to adhere to the jar as a thin surface, this purple was evidently deep and bright. An absorption of rather more than ⅛ of the volume of gas had taken place.
The blood in oxygene and atmospheric air, were of a much brighter tinge than that in any of the other gases. On the top, the color was vermilion, but no perceptible absorption had taken place.
The coagulum in nitrous oxide, when examined in the mass was dark, and hardly distinguishable in its color from venous blood; but when minutely noticed at the surface where it was covered with serum, and in its diffusion over the sides of the jar, it appeared of a fine purple red, a tinge brighter than the blood in nitrous gas. An absorption had taken place in this cylinder, more considerable than in any of the others.
In carbonic acid, the coagulum was of a brown red, much darker than the venous blood, and a slight diminution of gas had taken place.
In the hydrocarbonate,[190] the blood was red, a shade darker than the oxygenated blood, and a very slight diminution of the gas[191] was perceptible.
f. To human blood that had been saturated with nitrous oxide whilst warm and constantly agitated for four or five minutes, to prevent its uniform coagulation, oxygene was introduced; the red purple on the surface of it, immediately changed to vermilion; and on agitation, this color was diffused through it. On comparing the tinge with that of oxygenated blood, no perceptible difference could be observed. No change of volume of the oxygene introduced, had taken place; and consequently, no nitrous oxide had been evolved from the blood.
g. Blood, impregnated with nitrous gas, was exposed to oxygene; but after agitation in it for many minutes, no change of its dark purple tinge could be observed, though a slight diminution of the oxygene appeared to take place.
h. Blood that had been rendered vermilion in every part by long agitation in atmospheric air, the coagulum of which was broken and diffused with the coagulable lymph through the serum, was exposed to nitrous oxide; for some minutes no perceptible change of color took place; but by agitation for two or three hours, it evidently affirmed a purple tinge, whilst a a slight absorption of gas took place. It never however, became nearly so dark as venous blood that had been exposed to nitrous oxide.