100 THE CELL DOCTRINE. 



Thus far it is plain that the views of Prof. Huxley 

 accord with those of many eminent histologists and 

 physiologists, the result of whose observations have 

 been embodied in these pages, and his descriptions 

 will be accepted as undoubtedly accurate. More 

 widely, in common with the school of so-called 

 " physicists," of which he is one, does he differ in 

 his views in that which is yet to be considered, the 

 origin and ultimate fate of this "protoplasm," or 

 matter of life. According to Prof. Huxley, the 

 matter of life is composed of ordinary matter, and 

 again resolved into ordinary matter when its work 

 is done. Waste is constantly going on which must 

 be supplied by food, which is converted into proto- 

 plasm. A solution of smelling salts in water, with 

 an infinitesimal proportion of some other saline mat- 

 ters, contains all the elementary bodies which enter 

 into protoplasm, yet an animal cannot make proto- 

 plasm. And this is characteristic. It 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 the living 

 matter of life, which is appropriate to itself. There- 

 fore, in seeking for the origin of protoplasm, we 

 must eventually turn to the vegetable world. The 

 plant, however, takes carbonic acid, water, and am- 

 monia, and converts it to the same stage of living 

 protoplasm with itself, though some of the fungi 

 need higher compounds to start with; and no plant 

 can live on the uncompounded elements of proto- 

 plasnl^^djthe at>seiice of aiiy .(tee > the elements 

 renders the pfaiit unable to manufacture protoplasm. 



