Organic Connection Between Physical and Psychical 265 



Hence, as far as the female is concerned, the act of pairing 

 has come to depend upon this stimulus (acting of course on 

 a suitable internal physiological state). This is no more 

 strange in the bird than it is that in ourselves thoughts and 

 emotions of love well up at the sight of some tangible ob- 

 ject connected with the beloved." 13 



But it is in the sex function itself that the tendency to 

 overdo manifests itself with greatest force. In fact, the fa- 

 miliar and ominous expression "sexual excesses" as applied 

 to the human animal, indicates very truthfully w r hat is be- 

 fore us. The whole phenomenon of competing and fighting 

 among the males of all higher animals for possession of the 

 females, with its momentous consequences in dozens of ways, 

 may truly be said to rest back on the excessiveness of the 

 sex impulse and instinct. Since as a general rule the males 

 and females of animal species are approximately equal in 

 numbers, pairing off two by two, after the manner of the 

 population of Noah's ark, might occasion but little and mild 

 competition could each male and each female be satisfied 

 with one mate, in accordance with the allotment which the 

 numerical equality would make. And the pertinent question 

 may be raised in passing, would not such a mode of pairing 

 secure the perpetuation of the species quite as well as, pos- 

 sibly better than, the method which is so largely in vogue? 



Highly suggestive seems to me in this connection, observa- 

 tions I have recently been able to make on the mating hab- 

 its of one of the California "surf perches" (Cymatogaster 

 aggregatus). This is one of the numerous viviparous bony 

 fishes peculiar to our coast. The species under attention 

 lives quite normally, as far as one can see, in the aquaria of 

 the Scripps Institution ; so what may be assumed to be its 

 typical habits can be observed continuously. 



Strict monogamy appears to prevail in the species. At 

 least this is true with the specimens three males and four 

 females under observation, and so far as a particular breed- 



