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 nie then to conclude, that the soda in the blood exists in the form of the 

 sesqui-cai'bonate ; an inference which appears to me still to be most in harmony 

 Avith 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 mm-iate 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 31 G grs. of serum — a quantity of the 

 alkali, which, Avhen dissolved in the same bulk of water, is more than sufficient 

 to give a precipitate with mmlate 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 tfie blood and serum of the ox and 

 sheep, at a favourable time of the year, during the Avinter season, when the tem- 

 perature of the air has been little above the freezing point. 



2. On the Viscid 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 

 sepai'ating the fibrin by straining through linen. 



Tlie cruor thus obtained is essentially a semifluid, the particles loosely ad- 

 hering foiTuing a mass in some respects not luilike honey or molasses. I shall 

 notice some appcai-ances 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. 



