mp3. NATURAL SELECTION ANDY LAMA RECRISM. 345 
surface, it is minutely ascertaining the texture, so to speak, of the 
organic or inorganic substances submitted to the ordeal of its keen 
judgment, and by the general structure and softness of the particles 
or fibres it determines whether they shall be accepted as digestible 
_ food or avoided as injurious or innutritious. It detects and rejects 
sand, earth, grass, leaves, or other unpromising material with which 
men from mere laziness, or the pressure of famine, would otherwise 
gratify their hunger, to the injury of the whole system." It discovers 
and enables us to remove such objects as fish-bones, hair, feathers, 
and pieces of grit (which latter, as I have personally experienced, may 
splinter a tooth) and so saves internal organs from injury by their 
accumulation or friction, and from waste of digestive activities. The 
tongue also delicately manipulates the food, and secures its proper 
mastication by pushing it between the teeth, while carefully avoiding 
being bitten between the little grinding mills and cutting machines 
amid which it works so deftly and yet so safely. It is the highly 
and wonderfully discriminative guardian and janitor of the whole 
alimentary canal, and the supreme judge of the quality, composition, 
and admissibility of the nutriment which is the foremost essential of 
‘life. If Natural Selection cannot evolve a very special degree of 
sensitiveness in the tongue, it is hard to see what it can evolve. Mr. 
Spencer, however, contends that ‘‘noadvantage is gained” by the 
explorations of the tongue, that the extreme perceptiveness of its tip 
is not needed, that use-inheritance furnishes the only possible explana- 
tion, and that even if tactile sensibility is of use in detecting fish-bones 
and foreign bodies among the food, a degree of sensitiveness equal to 
that of the finger-tip (which is only half as sensitive as the tongue-tip) 
would have been sufficient. But who can fairly undertake to decide 
that the higher degree of sensitiveness in an important food-selecting 
organ would never promote the well-being of individuals so far as to 
lead to survival where others perished ? If, moreover, lower powers 
occasionally led to elimination while surplus powers did not, there 
might easily be an evolution of surplus powers—a principle which will 
help to explain many of our keener and finer powers of eye and ear 
and brain, and the surplus powers of organs generally. 
In all cases of minor advantages, especially those of economy 
and lightness, it must constantly be borne in mind that the survival 
test acts more specially and most strongly in occasional crises—such 
as those of illness, famine, war, accident, and other perils—through 
some of which all of us still have to pass from infancy onwards. In 
such cases, exceedingly minute advantages may sometimes turn the 
scales of life and death. Even now, although the rigour of Natural 
Selection is so greatly mitigated under civilisation, a slightly 
healthier, stronger, and better nourished body, due to lessened waste 
11 Some tribes, when hungry or starving, partly evade or deceive this tactile 
sensitiveness and repugnance by filling their empty stomachs with a fine clay, ora 
fine, flour-like powder composed of exceedingly minute shells. 
