ON THE PHYSICAL BASIS OF LIFE 107 



with a profounder meaning than the Roman poet at- 

 tached to that melancholy line. Under whatever dis- 

 guise it takes refuge, whether fungus or oak, worm or 

 man, the living protoplasm not only ultimately dies and 

 is resolved into its mineral and lifeless constituents, but 

 is always dying, and, strange as the paradox may sound, 

 could not live unless it died. 



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 duration of the proprie- 

 tor'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 proto- 

 plasm. 



Every word uttered by a speaker costs him some 

 physical loss ; and, in the strictest sense, he burns that 

 others may have light so much eloquence, so much 

 of his body resolved into carbonic acid, water, and urea. 

 It is clear that this process of expenditure cannot go on 

 for ever. But, happily, the protoplasmic peau de cha- 

 grin differs from Balzac's in its capacity of being re- 

 paired, and brought back to its full size, after every 

 exertion. 



For example, this present lecture, whatever its intel- 

 lectual worth to you, has a certain physical value to me, 



