132 
LAWS OF YAEIATIOIL 
Chap. V. 
this system being functionally disturbed in the parents, 
I chiefly attribute the varying or plastic condition of 
the offspring. The male and female sexual elements 
seem to be affected before that union takes place which 
is to form a new being. In the case of sporting ” 
plants, the bud, which in its earliest condition does not 
apparently differ essentially from an ovule, is alone 
affected. But why, because the reproductive system is 
disturbed, this or that part should yary more or less, we 
are profoundly ignorant. Nevertheless, we can here 
and there dimly catch a faint ray of light, and we 
may feel sure that there must be sonie cause for each 
deviation of structure, however slight. 
How much direct effect difference of climate, food, 
&c., produces on any being is extremely doubtful. My 
impression is, that the effect is extremely small in the 
case of animals, but perhaps rather more in that of 
plants. We may, at least, safely conclude that such 
influences cannot have produced the many striking 
and complex co-adaptations of structure between one 
organic being and another, which we see everywhere 
throughout nature. Some little influence may be attri¬ 
buted to climate, food, &c.: thus, E. Forbes speaks 
confidently that shells at their southern limit, and when 
living in shallow water, are more brightly coloured than 
those of the same species further north or from greater 
depths. Gould believes that birds of the same species 
are more brightly coloured under a clear atmosphere, 
than when living on islands or near the coast. So with 
insects, Wollaston is convinced that residence near the 
sea affects their colours. Moquin-Tandon gives a list 
of plants which when growing near the sea-shore have 
their leaves in some degree fleshy, though not elsewhere 
fleshy. Several other such cases could be given. 
The fact of varieties of one species, when they range 
