of the Blood of Cholera Patients. 349 



uppermost portion was 1-0533, while that of the undermost 



was 1-0699. 



I got another specimen of blood from the heart; it was 

 very imperfectly coagulated, and very viscid : its specific gra- 

 vity was 1 -1020. This blood did not by standing separate into 

 two parts. The portion at the surface, after standing twenty- 

 four hours, was as heavy as that at the bottom. 



The great difference between the specific gravity of the 

 serum of cholera blood and that of the serum of healthy blood 

 is very remarkable. The mean specific gravity of the serum 

 of healthy blood is 1-0287; while that of the five specimens of 

 the serum of cholera blood stated above is 1*0506. 



Cholera serum coagulates at the usual temperature, namely, 

 when heated to 159°. 



II. Proportion between the Serum and Crassamentum of 



Cholera Blood. 

 No doubt the proportion between the serum and crassa- 

 mentum varies somewhat in different specimens of healthy 

 blood. However, this variation is confined within very narrow 

 limits; and perhaps we shall not deviate from the truth if we 

 state the quantities of serum and crassamentum in one hun- 

 dred parts of healthy blood as follows : 



Serum 55 



Crassamentum ^■5 



100 

 But in blood drawn from cholera patients these proportions 

 are very nearly reversed. The method which I employed to 

 determine the proportion of these two constituents was this. 

 The blood was allowed to coagulate, and its weight deter- 

 mined by weighing it in the vessel in which it was contained. 

 As much of the serum was then poured off as possible : the 

 crassamentum was then poured upon a cotton cloth, and left 

 for twenty-four hours till all the serum that would had dropped 

 through the cloth. The weight of the remaining crassamen- 

 tum was then determined. This deducted from the original 

 weight of the blood gave the serum which had been separated 

 from it.— The following Table exhibits the proportions be- 

 tween the serum and crassamentum of the five specimens of 

 cholera blood, the specific gravities of the serum of which are 

 given in the preceding page. 



1. Pure yellow serum, except the last drop or two, which 

 were tinged red. 



Serum 32-34 



Crassamentum 67'66 



100-00 



2. The 



