1890 PHYSIOLOGICAL SELECTION 175 



in the formation of species, Mr. Eomanes called his 

 theory ' physiological selection.' 



Physiological selection is conceived of as co- 

 operating with natural selection, the former allowing 

 the latter to act by interposing its law of sterility, 

 with the result that the secondary specific characters 

 may be either adaptive or non-adaptive in character. 



To Miss C. E. Romanes. 



Aix-les-Bains: May 1886. 



The Linnean Society paper went off admirably. 

 There was a larger attendance than ever I saw there 

 before. But this may have been partly due to the 

 president (Lubbock) having had a paper down for the 

 same evening. He was considerate enough to with- 

 draw it at the last moment so as to leave all the 

 evening for mine. I spoke for an hour and a half, and 

 the discussion lasted another hour. The paper itself 

 I have brought with me here, and am now putting the 

 last touches upon it. 



Probably I shall have to try the rat experiment 

 again, if the young ones show no signs of piebalding. 

 But look at them occasionally to see. 



There would be no use in getting the parrot to 

 make a gesture sign at the same time as he makes a 

 verbal one ; for, as you say, he would only show that 

 he can establish an association between a phrase and 

 a thing (whether object, quality, or action), and about 

 this there is no question. The question is whether 

 he can use verbal signs, not only as stereotyped in 

 phrases (when they are really equivalent to only one 



