48 Trans. Acad. Sct. of St. Lows 
an inventory, and inasmuch as we are all of a scientific 
turn of mind, let us consider certain fundamentals which 
seem to lie at the root of our troubles before we attempt 
to answer the questions. Without a diagnosis as to the 
causes of a comatose condition, we are rendered all the 
more helpless in the treatment which might be applied 
and the prognosis becomes more guarded. 
We all of us realize what is meant by natural selec- 
tion, and throughout the entire biological world we see 
evidences of limited adaptation to the existing environ- 
ment. There is probably no plant or animal which is per- 
fectly adjusted to its surroundings because both are sub- 
ject to certain more or less definite variations. The laws 
of natural selection operate almost entirely through 
selective breeding and the living form, having once been 
forced in a given direction, presently tends to overdo the 
very thing which made the survival possible. It attains 
a sort of hair-trigger balance to the conditions about it, 
and the more perfect the adaptation, the relatively less 
change in the conditions required to eliminate it. The 
sport-form tends to disappear and the throw-back gains 
the ascendancy and things go back to where they came 
from, or snuff out. I need only call your attention 
to the structural adaptation in the rodent in which the 
incisor teeth grow throughout the life of the animal. If 
now this animal is placed under conditions where the 
teeth may not be ground off as they grow, then these 
same teeth through their growth will finally lock the jaws 
of the animal and it may starve to death in the midst of 
plenty. Dave Harum’s suggestion ‘‘that a reasonable 
number of fleas is good for a dog’’ contains more sense 
than nonsense. 
We marvel at the conditions which made possible the 
enormous reptile forms of geological times. We are not 
