47 



we ever knew, that it is the presence of this instinct that 

 makes egg production possible. 



CONDITIONS OF REPRODUCTION. 



What are the conditions of reproduction? They are five, 

 .and they are as follows : 



1. Maturity. The animal, bird or plant must be in the in- 

 termediate state between growth and decay. The desire for 

 reproduction is greater at the beginning of this intermediate 

 state, and steadily declines toward its end. This is why a 

 fowl will lay more eggs the first year after coming to maturity 

 than in any subsequent year of her life. 



2. Vitality. Reproduction draws upon the vital forces as 

 does no other act. This is why the bird feels a desire to in- 

 cubate after her litter is completed she needs rest. The 

 broody hen should be treated with great consideration, and 

 not ruthlessly abused, as is too often the case. The imme- 

 diate effect of disease or injury is to weaken the desire for 

 reproduction. A sick hen is not a laying hen. 



3. Nutrition. The animal, bird or plant must be well fed. 

 Darwin makes nutrition the principal factor in reproduction. 

 He says : "With hardly an exception our domesticated ani- 

 mals, which have long been habituated to a regular and 

 copious supply of food, without the labor of searching for it, 

 are more fertile than the corresponding wild animals. The 

 amount of food affects the fertility of even the same indi- 

 vidual ; thus sheep, which on mountains never produce more 

 than one lamb to a birth, when brought down to lowland 

 pastures, frequently bear twins. As Mr. Dixon has remarked, 

 "*High feeding, care and moderate warmth induce a habit of 

 profligacy which becomes in some measure hereditary/ " 

 (Animals and Plants Under Domestication, vol. ii, chap, xvi.) 



4. Sanitation. Sanitation profoundly affects vitality, and 

 without sanitation the other conditions cannot produce their 

 full effect. The hen house should be kept perfectly clean, the 

 Thirds free from parasites ; they should not be crowded, and 

 should be supplied with everything necessary to comfort and 

 health. 



5. Sex. In the very lowest forms of life reproduction is 

 a sexual that is, the new life is produced not by the coming 

 together of male and female, but by fission or cleavage from 

 the parent organism. But all higher animals and plants are 

 represented by distinct male and female forms, and the more 



