546 Blood Volume in Relation to Weight and Surface Area. 



(2) In normal healthy mammals (rabbit, guinea-pig, and mouse) the blood 

 volume is satisfactorily expressed by the following formula, B = W^/7u, where 

 B is the blood volume in cubic centimetres, W the weight of the individual 

 in grammes, and k a constant to be ascertained for each particular species of 

 animal. This formula indicates that the smaller animals of any given 

 species, which have a relatively greater body surface than heavier ones, have 

 also a relatively greater blood volume. That is to say, that the blood volume 

 can be expressed as a function of the surface area. It is therefore misleading 

 to express the blood volume as percentage of the body weight, as has hitherto 

 been invariably done. 



(3) The constant k, by means of which the blood volume in cubic 

 centimetres can be calculated from our formula B = W^k when the weight 

 of the animal in grammes is known, is approximately, for — 



Eabbit . . . 

 Guinea-pig 

 Mouse 



1-58 

 3-30 

 6-70 



