BLOOD 265 



the drop neither rises to the surface nor sinks 

 to the bottom but swims with the mixture. If 

 the drop rests upon the surface, add benzol in 

 a similar manner. When the drop neither sinks 

 nor floats, its specific gravity must be that of the 

 benzol-chloroform mixture. Pour the mixture 

 into a glass cylinder, through a piece of linen to 

 hold back the blood-drop, and take the specific 

 gravity of the benzol-chloroform with an areom- 

 eter. The result is also the specific gravity of 

 the blood. 



The values obtained are slightly too low. The 

 error is one unit in the third decimal place. 



Determine the specific gravity of the blood 

 under the following conditions. Eecord the re- 

 sults in the laboratory note-book. Hand to the 

 instructor a copy of your observations written in 

 ink upon a laboratory blank. The material col- 

 lected by the class will be analyzed statistically 

 by a committee and a report made. 



1. The specific gravity of the blood in a healthy 

 man. 



2. In the same man half an hour after drink- 

 ing 750 c.c. of water. 



3. In the same man one hour after drinking 

 750 c.c. of water. 



4. In the same man after profuse sweating. 

 Note any feeling of thirst. 



