-4. Thumb. 
2. Index. 
OE a 
7. Index. 
6. Thumb. 
3, Aliddile. 
O¢ 
8, Middle. 
5. Little 
10. Little. 
9. Ring. 
FINGER AND TOE PRINTS OF AN ORANG OUTANG 
If the reader will compare these prints with the tips of his own fingers, he will see that they are 
not very dissimilar; he will also find on inspection, what he has possibly never before 
noticed, that his own toes have equally distinct and well-marked patterns. 
Most of the 
patterns are common both to man and his humble kin, and no one but an expert, seeing 
one of the above prints, could declare that it had not been made by a human being. 
The 
study of friction-skin furnishes, among other things, good evidence in support of the 
doctrine of evolution. 
simple transverse lines around the tail, 
so that in the act of grasping they would 
be parallel to the long axis of the branch 
around which the tail was _ coiled. 
Clearly, then, papillary ridges are 
primarily connected with the grasping 
power, and when they are intended 
solely for that function, they are so 
arranged as to be parallel to the axis 
of the object grasped. As regards this 
function of the papillary ridges, Dr. 
Hepburn observes that, although they 
are comparatively low, ‘yet they must 
cause a certain amount of friction, and 
thereby prevent slipping, while the 
naturally moist and clammy condition 
of the palm and sole of monkeys must 
be of material assistance to the firmness 
of the grasp. A man instinctively 
moistens the palms of his hands when 
he wishes to make his grasp more 
secure; and the grasping power of 
Photograph by Gertrude M. Sullender. 
(Fig. 15.) 
monkeys must be considerably increased 
by the application of the numerous 
papillary ridges which are capable of 
intimate adaptation to the surface of 
the object grasped.’ ”’ 
DARWINIAN SPECULATIONS 
One may admit that a fully developed 
friction-skin may be useful, and yet 
refuse to believe that its origin is due 
to natural selection. We are asked to 
believe that the monkey in whose palms 
a slight transverse corrugation appeared 
would be less likely to slip from the limb 
and fall into the jaws of the waiting 
carnivore below; we are also asked, 
in explanation of longitudinal ridges 
in the hand, to believe that a fruit would 
less often slip from the hand of the 
monkey in which these first appeared, 
and therefore he would be the venerable 
sire of a well-endowed progeny, when 
315 
