84 Scientific Proceedings (48). 



anastomosing branches were ligated lived only about 8 hours. 

 If the lungs and most of the skin were excluded by tying the 

 pulmocutaneous and anastomosing arteries, the frogs lived about 

 6 hours and if the mouth also were excluded by sewing this and the 

 nostrils shut and tying the cutaneous arteries, they lived about 

 43^ hours. Control frogs kept at this temperature, showed no 

 deviation from normal excepting slight over-excitability. 



These results show with how little gas exchange frogs can 

 live and also the large factor of safety with which their respiration 

 is normally provided. Auer and Meltzer have recently shown 

 that dogs could live with a supply of oxygen only one tenth of 

 that which they normally consumed. 



The results also show the great increase in the requisite gas 

 exchange with rise of temperature and the inability of the skin 

 respiration of the frog to support life at even moderately high 

 temperatures, at which the lungs and mouth alone are still sufficient. 



62 (671) 



Variations in the response of different arteries to blood 

 serum and plasma. 



By HUGH A. STEWART and SAMUEL C. HARVEY. 



Recent work by Brodie, Sollmann, and O'Connor has shown 

 that the blood contains substances acting on the vasomotor 

 apparatus other than suprarenin. Even before the work of these 

 investigators it had been noticed by Stevens and Lee that the 

 use of defibrinated blood for the perfusion of isolated organs 

 was often unsatisfactory because of the gradual diminution in 

 outflow. This was not investigated thoroughly until 1900 by 

 Brodie. He observed that the injection of blood serum into the 

 jugular vein of a cat caused an immediate fall in blood pressure. 

 The cat's own serum was as efficient in this respect as the serum 

 of any other animal. The cat, however, is the only animal which 

 responds in this manner, for Brodie's experiments were negative 

 on the dog and rabbit. The mechanism in this case appears to 

 be a reflex inhibition of the vasomotor center from excitation of 

 the pulmonary branches of the vagus. The importance of Brodie's 

 work lies in the fact that he was the first to show that plasma and 



