2/6 FROM FISH TO PHILOSOPHER 



fact that it is a diving mammal. The diving reflex is 

 unique to the diving mammals, and oxygen-lack has no 

 such action in other mammals; in man it induces, on the 

 contrary, a slight to moderate increase in renal blood flow 

 and filtration rate {62, p. 441}. 



Forster {115} has shown that if one closes the nostrils 

 of the ordinary white rabbit, the animal rapidly asphyxi- 

 ates and will die in convulsions without reduction in the 

 renal circulation; but if it is presented with a noxious 

 olfactory stimulus (whiffs of cigarette smoke), a reflex 

 entirely similar to the diving reflex is elicited in which 

 the renal circulation is sacrificed. Though cigarette smoke 

 is an artificial stimulus, it is conceivable that some com- 

 parable stimulus acts on the rabbit when it is in the 

 depths of its burrow, and possibly serves to conserve 

 oxygen. The presence of some such reflex may explain 

 the great lability of the renal circulation in this species 

 {62, p. 535 0- 



XII. MAN 



163. Cold Spring Harhor Symposia on Quantitative Bi- 

 ology. Volume XV. Origin and Evolution of Man. 

 The Biological Laboratory, Cold Spring Harbor, 

 L. I., New York, 1950. 



164. Commemoration of the Centennial of the Publica- 

 tion of The Origin of Species by Charles Darwin. 

 Proceedings of the American Philosophical Society, 



103: 153-319. 1959. 



165. Herrick, C. J. An Introduction to Neurology. W. 

 B. Saunders Company, Philadelphia, 5th ed., 1931. 



166. HowELLS, W. W. Origin of the human stock. Con- 

 cluding remarks of the Chairman. {See 163, p. 79.} 



167. Krogman, W. M. Classification of fossil men. Con- 

 cluding remarks of the Chairman. {See 163, p. 



119-} 



168. Morton, D. J. Human origin. Correlation of pre- 

 vious studies of primate feet and posture with other 



