460 



Further Experiments upon the Blood Volume of Mammals and its 



Relation to the Surface Area of the Body. 

 By Georges Dbeyek, M.A., M.D., Professor of Pathology in the University 



of Oxford, and William Pay, M.B., B.Sc, Philip Walker Student in the 



University of Oxford. 



(Communicated by Prof. Francis Gotch, F.R.S. Eeceived October 24, — Read 

 December 7, 1911.) 



(From the Department of Pathology, University of Oxford.) 



(Abstract.) 



In a previous paper* dealing with the blood volume of mammals kept in 

 captivity, such as tame rabbits, guinea-pigs, and mice, we have shown that 

 the blood volume is a function of the surface, and can be expressed by the 

 formula B = W*/&, where B is the blood volume in cubic centimetres, 

 W the weight of the animal in grammes, and Jc a constant calculated from 

 the experiments, and varying for each species of animal. 



In the present paper we have extended our observations upon the blood 

 volume to animals living a natural life in the wild condition, such as hares, 

 wild rabbits, and wild rats. The technique employed was exactly the same 

 as In our previous paper. 



The results obtained are in complete accord with our previous experiments, 

 in that the blood volume of each of the wild animals in question is a function 

 of the surface. The constant, determined from the experiments, and from 

 which the blood volume of these animals can be calculated according to the 

 formula B = W*/k, is for — 



Hare 0"94^ Tame rabbit... P58-) 



Wild rabbit .. . 2 - 04 >New series. Guinea-pig ... 3 - 30 y Old series. 

 Wild rat 3-05 J Mouse 6'70J 



For all experimental work where the blood volume is concerned, it is 

 necessary to know, not only what the absolute blood volume is, but also, 

 what is equally important, the magnitude of the deviations from the average 

 which may be met with in normal and healthy individuals, since otherwise it 

 is impossible to decide whether the blood volume found by experiment is to 

 be considered normal or abnormal. 



Calculating from the total number of our experiments by the method of 

 least squares, the mean deviation is found to be about 6 per cent. This 



* Dreyer, Georges, and Eay, William, 'Phil. Trans.,' 1910, B, vol. 201, pp. 133—160. 



