54 DR DAVY’S OBSERVATIONS ON BLOOD AND MILK. 
immersed unmixed, or after admixture with a little acid. In the one instance no 
air bubbles are disengaged ; in the other very many. 
Some years ago, when engaged in experiments on the blood, especially in 
relation to the present question—the condition of the alkali in it—I noticed the 
effect of cream of tartar in expelling carbonic acid, and that both from venous and 
arterial blood, and from serum; an effect which, with other considerations, in- 
duced me then to conclude, that the soda in the blood exists in the form of the 
sesqui-carbonate ; an inference which appears to me still to be most in harmony 
with the facts.* 
In opposition to this view, perhaps, it may be said, that farther proof of its 
correctness ought to be afforded by the effect of a solution of muriate of lime on 
the serum,—that, if the latter contain the alkali as stated, a precipitate of carbo- 
nate of lime ought to be the result. This experiment I have tried, with the aid 
of the air-pump, sometimes with a doubtful result, sometimes with a negative 
one, especially in the instance of serum from venous blood. But in these instances 
I have also found the result the same, even on the addition of a portion of sesqui- 
carbonate of soda, as much as ‘2 of a grain to 316 grs. of serum—a quantity of the 
alkali, which, when dissolved in the same bulk of water, is more than sufficient 
to give a precipitate with muriate of lime. Would not this seem to indicate that 
in the blood and its serum the carbonated alkali is in a peculiar state of combina- 
tion with the animal matter; and the same remark is applicable to the posphates 
or their elements. 
The trials referred to have been made on the blood and serum of the ox and 
sheep, at a favourable time of the year, during the winter season, when the tem- 
perature of the air has been little above the freezing point. 
2. On the Viserd Quality of the Blood Corpuscles. 
That the corpuscles of the venous blood of the mammalia, when quite fresh, 
and in the act of coagulating, collect together in piles, as it were by a kind of at- 
traction, is well known. The viscid, adhesive quality, I am about to notice, is 
distinct from this, and, indeed, is best seen when the aggregation in piles ceases 
to be witnessed, as in cruor, procured by breaking up the crassamentum, and 
separating the fibrin by straining through linen. 
The cruor thus obtained is essentially a semifiuid, the particles loosely ad- 
hering forming a mass in some respects not unlike honey or molasses. I shall 
notice some appearances connected with and indicating the condition referred to. 
When poured into a fluid, such as water or serum, it rapidly falls to the bot- 
* Physiological and Anatomical Researches, ii. p. 152. 
