424 BLOOD AND LYMPH. 



as possible and weighing the quantity of blood thus obtained, and 

 afterward washing out the blood-vessels with water and estimating 

 the amount of hemoglobin in the washings. The results are as 

 follows: Man, 7.7 per cent. ( T V) of the body- weight ; that is, a man 

 weighing 68 kgms. has about 5236 gms., or 4965 c.c, of blood in his 

 body; dog, 7.7 per cent.; rabbit and cat, 5 per cent.; new-born 

 human being, 5.26 per cent.; and birds, 10 per cent. The dis- 

 tribution of this blood in the tissues of the body at any time has 

 been estimated by Ranke,* 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 f is re- 

 covered from easily, while a loss of 4.5 per cent., more than half 

 the entire blood, will probably prove fatal. In cats a hemorrhage 

 of from 2 to 3 per cent, of the body-weight is not usually followed 

 by a fatal result. Just what percentage of loss may be borne by the 

 human being has not been determined, but it is probable that a 

 healthy individual may recover without serious difficulty from the 

 loss of a quantity of blood amounting to as much as 3 per cent, of 

 the body-weight. It is known that if liquids that are isotonic to 

 the blood, such as physiological saline (Nacl, 0.7 to 0.9 per cent.) 

 or Ringer's solution, are injected into the veins immediately after 

 a severe hemorrhage, recovery is more certain ; in fact, it is 



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

 Daten und Tabellen," Jena, 1893. 



fFredericq: "Travaux du Laboratoire" (Universite de Liege), 1, 189, 



1885. 



