THE HORMONES IN HUMAN REPRODUCTION 



The induction of lactation in pregnancy is thus another 

 example of those remarkable integrative linkages among the 

 various parts of the reproductive system by means of hor- 

 mones, by which shelter, warmth, and nourishment are pro- 

 vided for the mammalian egg while it is incubated within the 

 body and at the breast of its mother. By such extraordinary 

 means as this have the children of men, latest of a long series 

 of creatures to haunt the earth, been protected from isolation 

 and danger in their earliest days, and given time to grow for 

 nine months before being exposed to the rigors of the outer 

 world. This privilege of uterogestation, which would be im- 

 possible without the ovarian and placental hormones, gives 

 an incalculable advantage to mankind and the other mammals 

 in the struggle for superiority in the animal kingdom. 



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{ IBU) 



