160 
THE PRINCIPLES OF BIOLOGY. 
THE PRINCIPLES OF BIOLOGY. 
BY HERBERT SPENCER. 
EXPOSITION OF CHAPTERS Y. AND VI. 
“ The correspondence between life and its circumstancesand “ The 
degree of life varies as the degree of correspondence 
BY J. 0. W. BARRATT, B.SC. 
The proximate definition of life given in Cliap. IV. does 
not include that adaptation which is so characteristic of living 
beings. Although we make use of this fact to ascertain if an 
animal or plant is living—as when we rouse a horse lying 
down in a field, or when we watch a tree to see if it puts forth 
leaves in spring—nevertheless, from its very commonness, we 
usually overlook it, paradoxical though this may appear. 
Supposing, however, that beings of an entirely different order 
to mankind were to come to this earth, the adaptation would 
be the first thing they would notice. They would notice it 
among the throng in the streets, in the houses, everywhere. 
And the highest manifestations of this adaptation, such as the 
ease with which a captain finds his way on the sea, do strike 
us with wonder. Again, comparing the life of a man with 
that of a fish, this adaptation is seen to be two-fold. Not 
only is the individual suited to his external world, but, not 
less important, the external world must be suited to the 
individual—a man cannot live in water, nor a fish out of it. 
Thus the full conception of life of Chap. V. is arrived at. 
This conception has eluded the grasp of all previous genera¬ 
tions. The late M. Comte got within measurable distance of 
it, but it is only within our own times that Mr. Herbert 
Spencer has reached it, and no one can feel any enthusiasm 
for Mr. Spencer unless he realises this idea. 
He Blainville’s definition of life is very nicely illustrated 
by an amoeba, which might be defined as an entity in which 
food and oxygen were changing into waste products. In 
connection with these two chapters also, it is worth while 
calling to mind that it is by a number of amcebse clubbing 
together that a compound animal, such as the fresh-water 
Hydra, is produced. The principle of this union is division 
of labour, through which the life of each cell becomes easier, 
and the whole animal has greater scope for action. 
The differences in longevity exhibited by various forms of 
life sometimes appear to contradict Mr. Spencer’s views of 
