HORMONES AND REPRODUCTION 79 



ovary), and second they work together with these 

 hormones to induce the maturation and escape of the 

 germ cells. 



The gonad hormones may also exert a powerful stimu- 

 lus to cell division throughout the body, and thus they 

 cause the growth of the accessory sexual organs and 

 secondary sexual characters without which successful 

 breeding could not occur. 



In conclusion a word of caution is perhaps not out of 

 place. In handling such an abundance of evidence, most 

 of it inconclusive and much of it contradictory, it is 

 impossible to do more than to pass a personal opinion 

 as to what is significant and reliable. Another, judging 

 the same case, may be found to lay stress on different 

 parts of the narrative and even in some particulars to 

 arrive at different conclusions. In such a field of research, 

 which is still being exploited so vigorously, the future 

 still holds all the final answers. 



