PHYSICAL AND CHEMICAL CHARACTERS. 325 



protophyte. We must have recourse to very violent 

 devices of destruction to kill the cell at a blow, to 

 leave absolutely nothing of its organization- existing. 

 The protoplasm of yeast when violently crushed by 

 Biichner still possessed the power of secreting soluble 

 ferments. A powerful action, a very high temper- 

 ature, is necessary to obtain the result. A fortiori, 

 the difficulty increases in the case of complex organ- 

 isms, all of whose living elements cannot be attacked 

 at the same moment by the destructive cause. A 

 mechanical action, capable of destroying at one blow 

 all the living parts of a complex being, of an animal, 

 of a plant, must be of almost inconceivable power. 

 The blow of a Nasmyth hammer would not be strong 

 enough. 



The chemical alteration produced by a very toxic 

 substance distributed throughout the blood, and thus 

 brought into contact with each element, would produce 

 a disorganization which, however rapid it were, could 

 not be called instantaneous. And the same holds 

 good of physical agents. 



But these are not the processes of nature under 

 normal circumstances. They are accidents or devices. 

 We shall leave on one side their consideration and 

 we shall only deal here with the natural processes of 

 the organism. 



Imagine it placed in a medium appropriate to its 

 needs and following out without intervening com- 

 plications the evolution assigned to it by its 

 constitution. Experiment tells us that this natural 

 evolution in every case known to us ends in death. 

 Death supervenes sooner or later. For beings higher 

 in organization, which we can bring into closer and 

 closer resemblance to man, we find that they die of 



