210 



Scientific Proceedings (108). 



the normal level in 20-40 minutes. A rabbit in which fever was 

 induced by puncture of the corpus striatum gave a very rapid 

 fall (average 1.1 0 C. in 20 minutes) of temperature on three dif- 

 ferent days as a result of 7 per cent, acacia injections. 



In rabbits, therefore, acacia injections induce a mild tempera- 

 ture depression in health but a marked antipyretic effect in fever. 



Four dogs responded to 4 c.c. per kilo of 20 per cent, acacia 

 injected intravenously by increases in body temperature varying 

 from 0.9 to 1.8 °C. In one of these, however, a preliminary 

 depression of one half degree was observed. The normal tem- 

 perature was regained within from 3 to 8 hours after injection. 



Two dogs were given coli fever (method of Barbour and 

 Howard) and the usual increase in blood solids was noted. Fol- 

 lowing an intravenous injection of 4 c.c. per kilo of 20 per cent, 

 acacia in each dog reductions of 0.4 and 0.7 0 C. respectively were 

 noted within 20 minutes, with a corresponding diminution in the 

 total solids of the blood. This was followed however by a renewed 

 temperature rise in both cases. 



Intravenous acacia injections therefore raise the temperature 

 of normal dogs but in fever dogs exert a brief though marked 

 antipyretic action, accompanied by increased blood volume. 

 The latter phenomenon is obviously parallel to the antipyretic 

 effect of intravenous injections of 50 per cent, dextrose. 



115 (1575) 



Studies on salt action. Ill: The effect of hydrogen ion concen- 

 tration upon salt action. 



By L S. Falk (by invitation). 



[From the Department of Public Health, Yale School of Medicine.] 



Our recent studies of the effect of electrolytes upon the via- 

 bility of bacteria have indicated the important influence of even 

 slight variations in hydrogen ion concentration upon such phe- 

 nomena. Working with Bact. coli we find that hydrogen ion 

 concentrations above pH = 6.0 or below pH = 7.0 give a much 

 more rapid death rate than occurs when the pH is maintained 

 within these limits. Our experiments suggest that a very careful 



