The Pharmacology of Acetone. 



203 



turtle. In the experiments on intact animals acetone injected 

 intravenously produced a fall of blood-pressure amounting in 

 some cases to fifty per cent., especially in dogs when given in a 

 concentration of fifty per cent, in saline solution, and about 2-3 

 c.c. per kilo. But in a number of experiments smaller quantities 

 of acetone injected in a concentration of 25 per cent, in saline 

 solution produced a similar effect on the circulation. This 

 occurred almost uniformly in cats. Recovery was prompt, as a 

 rule, even when 50 per cent, acetone was given, but occasionally 

 low blood-pressure persisted for 2-3 minutes when larger amounts 

 were injected. The fall of blood-pressure was due to cardiac de- 

 pression, as was indicated by the fact that there was a correspond- 

 ing diminution in the volume of the kidney shown by oncometric 

 studies. That acetone in certain concentrations depresses heart 

 action was also observed in our experiments on the isolated heart. 

 Ten per cent, acetone in Ringer solution produced in all our 

 experiments arrest of the heart, and very frequently the same 

 effect was obtained with a five per cent, solution of acetone. 

 Recovery, however, was observed in all experiments, even when 

 the heart was perfused with ten per cent, acetone for several 

 minutes. Not infrequently a stimulating after-effect was ob- 

 served. That no permanent injury occurred was further shown 

 by the fact that repeated perfusion of the same heart was followed 

 by recovery. With low concentration of acetone no change in 

 the heart action was observed. 



Observations were also made on the behavior of the vagus 

 mechanism under the influence of acetone. In dogs, after repeated 

 injections of acetone, stimulation of the peripheral end of the cut 

 vagus with the interrupted current of moderate strength produced 

 prolonged inhibition of the heart. The vagus center seemed like- 

 wise to be affected by acetone as it was observed in some experi- 

 ments that heart action became much slower, especially after 

 large amounts were injected. But when acetone was introduced 

 after previous double vagotomy retardation of heart action was 

 hardly discernible. 



The effect of acetone on respiration was much more pronounced 

 than on circulation. In cats prolonged periods of apnea were 

 observed after moderate amounts of acetone were injected intra- 



