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 witli 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, 



