158 CRITIQUES AND ADDRESSES. [vn. 



which take place between males and females of either 

 stock under the same circumstances. Some go so far as 

 to assert that no mixed breeds of mankind can maintain 

 themselves without the assistance of one or other of the 

 parent stocks, and that, consequently, they must inevit- 

 ably be obliterated in the long run. 



Here, again, it is exceedingly difficult to obtain trust- 

 worthy evidence, and to free the effects of the pure 

 physiological experiment from adventitious influences. 

 The only trial which, by a strange chance, was kept clear 

 of all such influences the only instance in which two 

 distinct stocks of mankind were crossed, and their progeny 

 intermarried without any admixture from without is 

 the famous case of the Pitcairn Islanders, who were the 

 progeny of Bligh's English sailors by Tahitian women. 

 The results of this experiment, as everybody knows, are 

 dead against those who maintain the doctrine of human 

 hybridity, seeing that the Pitcairn Islanders, even though 

 they necessarily contracted consanguineous marriages, 

 throve and multiplied exceedingly. 



But those who are disposed to believe in this doctrine 

 should study the evidence brought forward in its support 

 by M. Broca, its latest and ablest advocate, and compare 

 this evidence with that which the botanists, as repre- 

 sented by a Gaertner, or by a Darwin, think it indispen- 

 sable to obtain before they will admit the infertility of 

 crosses between two allied kinds of plants. They will 

 then, I think, be satisfied that the doctrine in question 

 rests upon a very unsafe foundation ; that the facts 

 adduced in its support are capable of many other inter- 

 pretations ; and, indeed, that from the very nature of 

 the case, demonstrative evidence one way or the other 

 is almost unattainable. A priori, I should be disposed 

 to expect a certain amount of infertility between some of 

 the extreme modifications of mankind; and still more 



