2 METHOD EMPLOYED IN ANALYZING THE BLOOD. 



The capsule is then placed upon a chloride of calcium bath, and subjected to a 

 temperature of from 220° to 230° F. until it ceases to lose weight. Subtracting 

 the weight of the capsule from the last weight, we obtain the amount of solid matter 

 in the portion of blood under examination, and subtracting the solid matter from the 

 amount of blood employed, we ascertain the amount of water. 



To ascertain the amount of solid matter in 1000 jxtrts of blood, we use the follow- 

 ing proportion : — 



Weight of ) . ( Weight of| , , ,„„„ . (Proportion of solid matter 

 blood employed i (dry residue] tin 1000 parts of the blood. 



Having ascertained the solid matter in 1000 parts of blood, the amount of water 

 may be determined by simply subtracting the solid matter from 1000. 



The solid residue is next incinerated in a porcelain or platinum 1 crucible, until 

 all the carbonaceous portion is consumed, and a light-red or yellow ash remains. 

 A high heat and much care are indispensable in this process. 



Another method, recommended by Dr. R. E. Rogers, Professor of Chemistry in 

 the University of Pennsylvania, is to treat the dried residue with nitric acid, and 

 gradually boiling down, incinerate the remainder. The organic matter readily 

 dissolves in the hot nitric acid, and passes off in the form of gas. 



The proportion of fixed saline matter in 1000 parts of blood may be calculated 

 in the following manner: — 



Weight of \ ( Weight of ash ^ . 100 „ . (Proportion of fixed saline matter 



blood employed) (after incineration} I in 1000 parts of blood. 



From this portion of blood, we have now obtained — 



Water in 1000 parts. 

 Solid matter in 1000 parts. 

 Fixed saline matter in 1000 parts. 



Treatment of the Portion (b). 



The specific gravity of the blood is determined accurately with the balance. This 

 should be done immediately after the porcelain capsule containing the blood is 

 placed upon the chloride of calcium bath. 



Treatment of the Portion (c). 



The weight of the porcelain capsule, and the blood which it contained, is next 

 ascertained; and, subtracting the weight of the capsule, we have remaining that 

 of the blood. The blood is then to be set aside until it is completely coagulated, 

 and the serum separated from the clot. The length of time required for this varies 

 according to circumstances and the character of the animal. 



The specific gravity of the serum is next to be ascertained by means of a specific 

 gravity bottle holding one hundred grains. We then pour into a porcelain cap- 

 sule (the weight of which has been previously noted), from ten to fifty grains 



1 For general purposes, a crucible of porcelain is to be preferred to one of platinum. 



