294 THE POPULAR SCIENCE MONTHLY 



temperature and moisture, is somewhere between 2 million and 10,000 

 million ohms. 7 



It is conceivable that the grains of wheat exhumed with Egyptian 

 mummies would scarcely have retained their germinating power after 

 so many centuries had not nature clothed them with their insulating 

 shells, and passing from these diminutive little lives of eggs, grains 

 and cells, it is conceivable that this globe that we inhabit would itself 

 become a moving sepulchre, devoid of all molecular transformations of 

 energy, were it not for the external envelope of insulating atmosphere 

 with which it is clothed. Without this insulation the energy of solar 

 light and heat would no longer be transformed into things of beauty 

 and life; but would at once be dissipated into the abysses of space and 

 our earth would probably become as dead as the moon, which has no 

 insulating covering, and, consequently, upon whose face, within the 

 memory of man, no single change of feature has been observed. 



In the foregoing discussion my purpose has been to lay the founda- 

 tion for a modified definition of life. Every one is familiar with 

 Spencer's definition, viz: 



Life is the definite combination of heterogeneous changes, both simultaneous 

 and successive, in correspondence with external coexistences and sequences. 8 



Never, perhaps, did human language attempt to express so much in 

 so few words. In fact it is so condensed as to be difficult of compre- 

 hension. If the definition had been given first, few of us would ever 

 guess that life was the thing it intended to define. 



On page 80, Spencer says : 



The broadest and most complete definition of life will be: the continuous 

 adjustment of internal relations with external relations. 



De Blainville said : 



Life is the twofold internal movement of composition and decomposition 

 at once general and continuous. 



Criticizing this definition, Spencer remarks: 



It describes not only the integrating and disintegrating processes going on 

 in a living body, but it equally well describes those going on in a galvanic 

 battery which also exhibits a two-fold internal movement of composition and 

 decomposition at once general and continuous. 9 



At the time Spencer wrote (1866), biology was not sufficiently 

 advanced for him to realize that every cell in the body really was a 

 minute electric battery, and that the coordinate and simultaneous action 

 of millions of these batteries made up together the living body of a 

 complete animal. 



7 Science, December 4, 1908, p. 812, and Bulletin 99, 1907, Bureau of Plant 

 Industry, U. S. Department of Agriculture. 



8 " Principles of Biology," p. 74. 



9 " Principles of Biology," p. 60. 



