REGENERATION AND HEMORRHAGE. 469 



made to breathe a known volume of carbon monoxid for a certain time, and 

 the total amount of this carbon monoxid that is absorbed is ascertained by 

 analysis. A second specimen of blood is then taken and its volume per cent, 

 in oxygen is again determined. The difference between this volume per cent, 

 of oxygen and that obtained before the administration of the carbon monoxid 

 gives the volume per cent, of carbon monoxid in the blood, since the latter 

 gas displaces an equal volume o f oxygen. If the total amount of carbon 

 monoxid absorbed by the blood is indicated by V and the volume per cent., 

 that is, the number of c.c. to each 100 c.c. of blood, is indicated by v, then the 



total quantity of the blood will be given by the formula X 100. 



The average results obtained from numerous experiments are 

 as follows: The ratio of weight of blood to weight of body is, in the 

 dog, 7.7 per cent.; rabbit and cat, 5 per cent.; birds, 10 per cent. 

 On man we have upon record two determinations on guillotined 

 criminals made by Bischoff, which gave 7.7 and 7.2 per cent. 

 Haldane and Smith,* however, have devised a modification of 

 Grehant's carbon monoxid method, which they have applied to 

 living men. The results of some 74 experiments gave them an 

 average value of only 5 per cent, for man. The distribution of 

 this blood in the tissues of the body at any time has been esti- 

 mated by Ranke,f from experiments on freshly killed rabbits, as 

 follows : 



Spleen 0.23 per cent 



Brain and cord 1.24 " 



Kidneys 1.63 



Skin 2.10 



Intestines 6.30 



Bones 8.24 



Heart, lungs, and great blood-vessels 22.76 



Resting muscles 29.20 



Liver 29.30 



It will be seen from inspection of this table that in the rabbit the 

 blood of the body is distributed at any one time about as follows: 

 One-fourth to the heart, lungs, and great blood-vessels; one-fourth 

 to the liver; one-fourth to the resting muscles; and one-fourth to the 

 remaining organs. 



Regeneration of the Blood after Hemorrhage. A large 

 portion of the entire quantity of blood in the body may be lost 

 suddenly by hemorrhage without producing a fatal result. The 

 extent of hemorrhage that may be recovered from safely has been 

 investigated upon a number of animals. Although the results 

 show more or less individual variation, it may be said that in dogs 

 a hemorrhage of from 2 to 3 per cent, of the body- weight J is re- 



* Haldane and Smith, "Journal of Physiology," 25, 331, 1900; also Zuntz 

 and Pletsch, "Biochemische Zeitschrift," 47, 1908. 



f Taken from Vierordt's "Anatomische, physiologische, und physikalische 

 Daten und Tabellen," Jena, 1893. 



t Frederic, "Travaux du Laboratoire" (Universite de Liege), 1, 189, 1885. 



