14C oN Till: PHYSICAL BASIS OF LIFE m 



In the wonderful story of the " Peau de Chagrin," 

 the hero becomes possessed of a magical wild ass' 

 skin, which yields him the means of gratifying all 

 his wishes. But its surface represents the dura- 

 tion of the proprietor's life ; and for every satisfied 

 desire the skin shrinks in proportion to the 

 intensity of fruition, until at length life and the 

 last handbreadth of the peau de chagrin, disappear 

 with the gratification of a last wish. 



Balzac's studies had led him over a wide range 

 of thought and speculation, and his shadowing 

 forth of physiological truth in this strange story 

 may have been intentional. At any rate, the 

 matter of life is a veritable peau de chagrin., and 

 for every vital act it is somewhat the smaller. All 

 work implies waste, and the work of life results, 

 directly or indirectly, in the waste of protoplasm. 



Every word uttered by a speaker costs him 

 some physical loss ; and, in the strictest sense, he 

 burns that others may have light so muc-h 

 eloquence, so much of his body resolved into car- 

 bonic acid, water, and urea. It is clear that this 

 process of expenditure cannot go on for ever. 

 But, happily, the protoplasmic peau dc <//"//''? 

 differs from Balzac's in its capacity of being 

 repaired, and brought back to its full size, after 

 every exertion. 



For example, this present lecture, whatever its 

 intellectual worth to you, has a certain ph\>i< -al 

 value to me, which is, conceivably, expressible by 



