522 Proceedings of Royal Society of Edinburgh. [sess. 
the spleen due to its growth and to pressure of the surrounding 
viscera.” He further states it as his impression “ that the presence 
of a large vessel makes the spleen less inclined to bulge at that 
point and, combined with pressure, determines the site of the 
future notch.” This may be so, but one cannot forget that there 
are variations, both in number and depth, of the notches in spleens 
taken from the same species of animal, which do not appear to be 
explained on this view. The spleen of the horse and dog are not 
generally notched ; yet I have seen indentations (certainly not deep, 
but as certainly definite), in both animals, when the spleen was 
not larger than usual, nor was there any pathological change. It 
appears to me that any explanation of the causation of splenic 
notches must interpret the origin of the abnormal forms of spleen 
such as have been discussed by Haberer (25). The notches may 
be continued to such a depth that the spleen is truly lobulated. 
Eiirst (26) has quite recently described a case in the human 
subject where there were five separate and approximately equal 
lobes, which collectively reproduced the form of the normal organ. 
And Helly (27) only a few weeks ago reported upon a human 
spleen composed of two distinct parts, which, before they were 
separated, made up a spleen of normal form and size. Each of 
these parts, it should be noted, was deeply notched ; so that there 
were five lobes in each segment. It seems not too much to ask 
that an explanation of the normal notches should also account for 
the exuberance of the indentations in the above-mentioned and 
similar cases ; and that it should also take some cognisance of 
those accessory spleens which are occasionally so numerous, 
Albrecht (28) having found a very large number in one case. 
Fiirst thinks that comparative anatomy can throw some light upon 
these anomalies ; and also, we may suppose, upon the normal con- 
dition of which the abnormalities appear to be merely excesses. 
We may certainly expect that any satisfactory answer as to the 
meaning of the notches in the mammalian spleen will be given by 
comparative anatomy and embryology combined. The question 
has been gone into thus fully here because of the difference 
between the spleen of Gercocebus and that of Lagothrix , to be 
presently described. 
Kidneys . — The kidneys differ from each other very largely with 
