148 ON THE PHYSICAL BASIS OF LIFE m 



protoplasm into living lobster. Or, if nothing 

 better were to be had, I might supply my wants 

 with mere bread, and I should find the protoplasm 

 of the wheat-plant to be convertible into man, 

 with no more trouble than that of the sheep, 

 and with far less, I fancy, than that of the lobster. 



Hence it appears to be a matter of no great 

 moment what animal, or what plant, I lay under 

 contribution for protoplasm, and the fact speaks 

 volumes for the general identity of that substance 

 in all living beings. I share this catholicity of 

 assimilation with other animals, all of which, so 

 far as we know, could thrive equally well on the 

 protoplasm of any of their fellows, or of any plant ; 

 but here the assimilative powers of the animal 

 world cease. A solution of smelling-salts in water, 

 with an infinitesimal proportion of some other 

 saline matters, contains all the elementary bodies 

 which enter into the composition of protoplasm ; 

 but, as I need hardly say, a hogshead of that fluid 

 would not keep a hungry man from starving, nor 

 would it save any animal whatever from a like 

 fate. An animal cannot make protoplasm, but 

 must take it ready-made from some other animal, 

 or some plant the animal's highest feat of 

 constructive chemistry being to convert dead 

 protoplasm into that living matter of life which 

 is appropriate to itself. 



Therefore, in .sucking for the origin of proto- 

 plasm, we must eventually turn to the vegetable 



