WITH YEGETABLES. 9 



of their body being adapted to absorb and digest, they 

 have no need of a special receptacle for nutrient matter, 

 and accordingly have no stomach. This distinction then 

 is not a cardinal one. 



It would be tedious as well as unnecessary to enumerate 

 the chief distinctions between the more highly developed 

 animals and vegetables. They are sufficiently apparent. 

 It is necessary to compare, side by side, the lowest mem- 

 bers of the two kingdoms, in order to understand rightly 

 how faint are the boundaries between them. 



CHAPTEE II. 



ON THE RELATION OF LIFE TO OTHER FORCES. 







IN the foregoing chapter we have seen how life exhibits 

 itself most simply, how many and great differences there 

 are between living forms and those of inorganic matter, 

 how few and small distinctions between life as it is in the 

 lowest animal and the lowest vegetable. It will be well 

 now to examine very briefly what is the nature of life, 

 and how far it can be shown to have any relation to other 

 forces. 



Before attention had been drawn to the mutual conver- 

 tibility of the various so-called physical forces, heat, light, 

 electricity, etc., and before it had been shown that these 

 are limited and measurable, and no more to be created at 

 will than matter itself, it was not strange that life should 

 be considered, like them, a peculiar power, innate in 

 certain structures, but essentially independent of them, and 

 of the physical forces by which it was surrounded. When, 

 however, our ideas concerning these forces underwent a 

 complete revolution, it was to be expected that our notions 

 of life would suffer a radical change also. We know now 



