BLOOD. 63 



enzymes such as pepsin, trypsin, diastase, etc. The hypothesis u>rd to ex- 

 plain the action of peptone may possibly apply also to these cases. 



5. By the Action of Oxalate Solutions. — If blood as it flows from the 

 vessels is mixed with solutions of potassium or sodium oxalate in proportion 

 sufficient to make a total strength of 0.1 per cent, or more of these salts, 

 coagulation will be prevented entirely. Addition of an excess of water will 

 not produce clotting in this case, but solutions of some soluble calcium salt 

 will quickly start the process. The explanation of the action of the oxalate 

 solutions is simple : they are supposed to precipitate the calcium as insoluble 

 calcium oxalate. 



Total Quantity of Blood in the Body. — The total quantity of blood in 

 the body has been determined approximately for man and a number of the 

 lower animals. The method used in such determinations consists essentially 

 in first bleeding the animal as thoroughly as possible and weighing the quan- 

 tity of blood thus obtained, and afterward washing out the blood-vessels with 

 water aud estimating the amount of haemoglobin in the washings. The results 

 are as follows: Man, 7.7 per ceut. (y 1 ^) of the body-weight; that is, a man 

 weighing 68 kilos, has about 5236 grams, or 4965 c.c, of blood in his body; 

 dog, 7.7 per cent.; rabbit and cat, 5 percent.; new-born human being, 5.26 

 per cent. ; and birds, 10 per cent. Moreover, the distribution of this blood 

 in the tissues of the body at any one time has been estimated by Ranke, 1 from 

 experiments on freshly-killed rabbits, as follows : 



Spleen 0.23 per cent. 



Brain and cord 1.24 " " 



Kidneys 1.63 u 



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 thai can be 

 recovered from safely has been investigated upon a number of animals. 

 Although the results show more or less individual variation, it can be said 

 thai in dogs a hemorrhage of from 2 to 3 per cent, of the body-weight 8 is 

 recovered from easily, while a loss of 1.5 per cent., more than half the entire 

 bl 1, will probably prove fatal. In eats a hemorrhage of from 'J i<> •"» per 



'Taken from Vieronlt's Anatoimsche, physiologische >ni<l physikaltsche Daten "»'/ Tabellen,Jen&, 

 1893. 



2 Kredericq : Iravavx du LaftorotoiVe l University de LiSge), L885, t. i. p L89. 



