Relation of Blood- Volume to Nutrition. 



55 



of hemorrhage. It invariably produced a quieting effect upon the 

 dogs accompanied by a softness of muscle indicative of a marked 

 reduction in muscular tonus. It is possible that the decreased 

 demand for oxygen on the part of the tissues partly explains our 

 data. 



When carbon dioxide was allowed to accumulate in the re- 

 breathing apparatus as the oxygen percentage of the respired air 

 decreased, hemorrhage produced a definite decrease in tolerance 

 to the combined changes in carbon dioxide and oxygen. But the 

 restlessness of the animals under these conditions contraindicated 

 an effort at quantitative results without anesthesia. 



We have recently conducted a series of experiments on the 

 dog under morphine-ether, and morphine-urethane anesthesia. 

 In these experiments we compared the ventilation during the 

 administration of a mixture of carbon dioxide and room air with 

 that of room air — first with a normal blood volume, second after 

 hemorrhage, and third after the replacement of the blood with 

 gum-saline. Consistent results were obtained in 10 experiments. 

 The administration of a 5 per cent, mixture of carbon dioxide in 

 room air invariably increased the ventilation over that of room 

 air alone. The increase in ventilation was markedly augmented 

 by hemorrhage. In some cases the augmentation was excessive. 

 Subsequent injections of gum-saline reduced the response almost 

 to that obtaining before hemorrhage. Striking augmentation of 

 response to carbon dioxide mixtures resulted from hemorrhages 

 amounting to 1 per cent, of the body weight and less. In some 

 experiments changes in respiration were associated with the ad- 

 ministration of carbon dioxide alone. In other experiments the 

 ventilation of room air was increased by hemorrhage, and de- 

 creased by injection as well. 



These experiments, we believe, demonstrate that hemorrhage 

 amounting to 1 per cent, of the body weight or less may, under the 

 conditions employed in these experiments, produce a detrimental 

 effect upon the volume flow of blood, and that the injection of an 

 inert solution improves the circulation in such a way as to enhance 

 the gaseous exchange. 



