DIMENSIONS OF KIDNEY 



453 



From the figure the weights of the kidneys of whales of a series of body lengths can 

 be estimated and are given on p. 452. 



The left kidney only of thirty-five female Fin foetuses and thirty-five male Fin 

 foetuses were also weighed. In Table VI are shown the average weights of the kidneys 

 for foetuses of body lengths differing by i-o m. The weights of some of the foetuses are 

 also given. 



The weights of the foetuses were taken also with the spring balance. Foetuses too 

 large to be lifted whole had to be cut into two or more sections with much resulting 

 loss of blood. The larger the foetus, therefore, the less accurate the weighing. 



VOLUME OF THE KIDNEY 



The volume of the kidney was obtained as follows : 



Blocks of kidney substance of a convenient size were weighed and from the average 

 weight of a large number of such blocks, cut as uniformly as possible, the volume of 

 those kidneys whose weight is already known can be calculated. 



The size of the blocks of kidney substance used, was as nearly as possible, 20 x 20 x 5 

 cm. The average of 221 weighings of such blocks gave the weight of this mass of kidney 

 substance as 1 -82 kg. From this the volume of the kidneys whose weight is already 

 known can easily be calculated and is shown in Table V. 



With the small number of figures obtained it is not possible to make distinctions 

 between the sexes either in the case of the weights or the volumes of the kidneys, but 

 from the data already obtained for the linear dimensions of the kidney there is no reason 

 to suppose that any sexual difference exists. 



The following are the kidney volumes calculated from the weights derived from 



Fig- 37 : 



In the above estimations of the weight and volume of the kidney only Fin whales were 



dealt with, since no Blue whale foetal kidneys were weighed and insufficient foetuses 



were examined. 



DENSITY OF THE KIDNEY 



From the actual weight of the kidneys and from their calculated volumes it may be 



estimated that the density of the organ is 0-910. This is probably not far from correct 



since the kidney just floats in water. 



