266 SECRETS OF ANIMAL LIFE 
got something quite definite to say—something well 
deserving to be thought over—that the physiological ' 
condition of the parents at the time of re- 
production influences the next generation. What is 
meant is not that two hard-set, thick-skinned, tough- 
minded, and well-controlled parents are likely to 
have children after their own image, or that two 
slack, thin-skinned, flabby-minded, and _ feckless 
parents are likely to have children after their kind; 
for this would simply be the generally accepted 
doctrine that innate constitutional characters are 
entailed from generation to generation. Like tends 
to beget like; no grapes from thorns nor figs from 
thistles. But what Mr. Bonhote means is something 
different and something debatable. 
His argument is this. Changes or peculiarities in 
environmental conditions (including food, warmth, 
humidity, and so on) have an influence on the 
physiological state of susceptible organisms. Corre- 
sponding to the “ nurtural ” changes or peculiarities 
there are often internal changes in the metabolism. 
This is admitted by all biologists. But may it not 
be that the character of the metabolism, environ- 
mentally modified about the time of parentage, 
reacts on the germ-cells and affects them in some 
way, so that their development, i.c. their expression 
of the inheritance, is different from what it would 
have been if the parental constitution had not been 
affected by the nurtural modifications? In the 
author’s terminology, which we cannot accept, the 
altered vigor of the parents may affect the initial 
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