PRINCIPLES OF BIOLOGY. 
228 
profits, the street vendor being handicapped by absence of 
capital. A tree gets ahead of the herbage because, from the 
first, it is richly endowed with food. 
To Mr. Spencer’s summary of this chapter, as being 
far clearer than my exposition, the reader is referred. 
PRINCIPLES OF BIOLOGY. 
BY HERBERT SPENCER. 
Reply to Mr. Lawson Tait's Note. 
BY W. B. GROVE, B.A.* 
Mr. Lawson Tait’s note in last month’s “ Midland 
Naturalist ” raises so many questions that a brief reply must 
necessarily leave some of them untouched. Still, I think it 
can be shown that, in one or two respects at least, he falls 
short in some degree of the truth. We are glad that a dis¬ 
cussion has been raised, because it is chiefly by such means 
that the accused finds out the weak points in his armour, and 
the accuser has the chance of being converted. 
In the first place, it is surely necessary that he who 
attempts to criticise Herbert Spencer should have read Herbert 
Spencer carefully and well. But Mr. Tait’s reference to the 
“ contradiction” on p. 205, and his putting forward the ex¬ 
ample of Anacharis Alsinastrum again in the next paragraph, 
render it difficult to avoid the conclusion that he considers 
the opinions contained on that page as Herbert Spencer’s own. 
Now, all attentive readers of the Principles of Biology know 
that this view of the nature of an individual is being quoted 
from Dr. Carpenter and Professor Huxley, and is just that 
which Herbert Spencer denies. This is not a promising 
beginning for the critic. 
In the second place, it is essential, in comparing the life- 
activities of different species, that any particular comparison 
should be restricted to those which stand in the same line of 
descent. For while the general argument that “ the length of 
life varies as the degree of correspondence” is seen to be true, 
on the whole, by a general survey of the organic world,! yet 
* Mr. Barratt having intimated his intention of not making any 
reply at present, the Secretary of the Section has asked me to do so. 
f This theorem is proved by (Professor) Ray Lankester, in his 
“ Comparative Longevity,” published in 1870. This is avowedly based 
upon the “Principles of Biology,” which the author finds to give the 
key to the facts, so far as they are known. 
