24 Society for Experimental Biology and Medicine. 



It was found that, if distilled water, in quantities of from 5 c.c. 

 to 50 c.c., is slowly allowed to flow into the facial vein, the vis- 

 cosity of the blood is increased, but the increase is not consider- 

 able. The following experiment may serve as a sample : The 

 normal coefficient K, in a dog weighing 19.2 kilos, was 802.6 or 

 5.8 times greater than K for distilled water at 37 0 C. After the 

 injection of 10 c.c. of distilled water, the coefficient showed the value 

 786.0 or 6.0 times greater than distilled water at 37 0 C. Normal 

 saline solutions produce the reverse effect, i. e., the blood becomes 

 less viscous. In one case after injecting 10 c.c. of 0.7 per cent. 

 NaCl solution, the viscosity of the blood fell from 5.9 to 5.6 times 

 that of distilled water at 37 0 C. Concentrated solutions of dex- 

 trose (5 c.c.) injected into the facial vein bring about an increase 

 in the viscosity of the blood, which is more pronounced than that 

 produced by distilled water. About a half-hour after the injection 

 the coefficient K shows again its normal value. 



If from 3 c.c. to 5 c.c. of 10 or 25 Jo solutions of alcohol 

 in water are allowed to flow into the facial vein, the molecular 

 friction of the blood becomes greater. The same result can be 

 obtained by introducing the alcohol directly into the stomach or 

 duodenum. After an injection of 30 c.c. of a 25 Jo solution 

 into the stomach, the viscosity, determined 20 minutes later, showed 

 the value 608.09, as against 664.17, the normal coefficient. Thus, 

 instead of being only 7.0 times greater than that of distilled water 

 at 37 0 C, it changed after the injection to 7.7 times greater. An 

 equally decisive change occurred after injecting 40 c.c. of a 25 Jo 

 solution into the duodenum. A marked increase in viscosity 

 also follows subcutaneous administration of curare ; however, this 

 result is not evident until the respiratory muscles become par- 

 alyzed. 



Venous blood is slightly more viscous than arterial, but the 

 difference is often very insignificant. 



In all these determinations a direct parallelism exists between 

 the viscosity values and the specific gravity. When the viscosity 

 increases, the specific gravity increases also, and vice versa. Not 

 a single exception to this rule was observed. 



The viscosity was also determined in a dog having very large 

 thyroid bodies. The right gland weighed 57 gm., the left 52 gm. 



