128 



Scientific Proceedings (92). 



after the mixture has stood a few days the clot forms more slowly 

 and tends to remain soft. At this time the clot becomes more 

 firm if fresh serum, containing fibrin ferment is added as well as 

 tissue extract. When the mixture has stood for several weeks, 

 clotting can no longer be induced. 



185 (1363) 



The minimum number of respirations sufficient to maintain life. 



By A. L. Meyer and S. J. Meltzer. 



[From the Department of Physiology and Pharmacology, Rockefeller 

 Institute for Medical Research.] 



We have made experiments on the dog to determine how few 

 respirations will maintain life. Both artificial respiration of the 

 ordinary type and the spontaneous respirations of the animal 

 were used for this purpose. We will speak only of the results 

 obtained by the use of artificial respiration. 



Ether was used for the exposure of the trachea. A T-shaped 

 glass cannula inserted and firmly tied in the trachea was provided 

 with a respiratory valve, devised by Dr. Meltzer, which in turn 

 was connected with a source of air pressure. 



There are two series of experiments. In the first series curare 

 was injected to completely abolish the respiratory movements. 

 We began with two artificial respirations per minute continued for 

 periods varying from 40 to 80 minutes. In all of the 19 experi- 

 ments the dogs were living at the close of the period. The vagi 

 were intact in 12 experiments; they were cut in 7 experiments. 

 While the volume of air introduced was not measured, it was 

 obviously much below the total lung capacity. 



In the second series curare was omitted. A clamp was applied 

 to the trachea below the cannula as a precaution against the 

 entrance of air between the artificial respirations. There were 

 13 experiments. In 8 the vagi were intact. Of these two 

 survived. Four died in about 25 minutes; two died in about 75 

 minutes. In 5 experiments the vagi were cut. All died. 



