THE CELL DOCTRINE. 101 



These elements, carbon, hydrogen, oxygen, and ni- 

 trogen, are related to the protoplasm of the plant 

 as the protoplasm of the plant to the animal. But 

 protoplasm once produced, all the phenomena exhibited 

 by it are simply its properties, just as the phenomena 

 exhibited by water in its various states are properties. 

 They do not take place through the guidance of any 

 principle called " vitality," any more than the phe- 

 nomena of water take place by virtue of " aquosity." 

 Prof. Huxley can discover no halting-place between 

 the admission that protoplasm of one animal or vege- 

 table is essentially identical with and readily con- 

 verted into another, and the further concession that 

 all vital action may, with equal propriety, be said to 

 be the result of the molecular forces of the protoplasm 

 which displays it. The thoughts to which we give utter- 

 ance are the expression of molecular changes in proto- 

 plasm. These are admittedly so-called materialistic 

 terms. Yet Prof. Huxley says : " Nevertheless, two 

 things are certain: the one that I hold the state- 

 ment (above) to be substantially correct; the other, 

 that I, individually, am no materialist, but on 

 the contrary believe materialism to involve grave 

 philosophical errors." Such union of materialistic 

 terminology with the repudiation of materialistic 

 philosophy, he believes to be " not only consistent 

 with, but necessitated by sound logic." This he 

 proceeds to show in this manner : If it be supposed 

 that knowledge is absolute, that we know more ot 

 cause and effect than a certain definite order of suc- 

 cession of facts, and that we have a knowledge of 

 the necessity of that succession, then there is no 



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