VIVIPAROUS ANIMALS. 399 
The particular period of life at which the organs of repro- 
duction become qualified for the exercise of their peculiar 
functions, appears to be influenced by several circumstances. 
When the body arrives at maturity, in respect to size and 
strength, by slow degrees, as is the case with man, the term 
of puberty is proportionally distant from birth. On the other 
hand, when maturity of size and strength is quickly attain- 
ed, as is the case with rabbits, the term of puberty as quickly 
arrives. In all these cases, however, puberty precedes by 
months or years the maturity of the body. In the human 
race, puberty takes place at an earlier period in the female 
than in the male. Even among individuals of the same 
species, very remarkable differences prevail. In general, 
however, it is observed, that all those circumstances, whe- 
ther food or shelter, which accelerate the growth of the 
body, exercise a proportional influence on the reproductive 
system, so that the period of puberty is uniformly earlier 
in domesticated than in wild animals, and in those which 
are fed plentifully with food than in those which are scan- 
tily supplied. The same circumstances seem to operate 
in the production of ova, domesticated animals being more 
fertile than wild ones of the same species *. 
* There is a very remarkable difference in this respect between animals 
and vegetables; the reproductive system of the former exerting itself pre- 
maturely when the body is liberally supplied with nourishment, while in the 
latter a scanty supply of nourishment promotes, and a liberal supply retards, 
early flowering. A tree planted in a poor soil, or one unfavourable to its 
growth, will announce to the owner the unsuitableness of its situation by the 
production of flowers and seed, while the same species growing in a better, 
will not produce flowers, but merely increase in size. 
Many productive operations of horticulture depend upon this singular 
law. Dwarfing, laying bare some of the roots of trees in winter, trans- 
planting, paring off portions of the bark, and tying wires round the stems, 
are each calculated to diminish the supply of food sent to the branches, 
and are well known to accelerate the production of fruit, Many seeds, 
