190 SCIENCE FROM AN EASY CHAIR 



compound. It is not. Cell-protoplasm includes the 

 nucleus, that denser central body, and is a structure 

 consisting of " proteids " and of many granules and 

 dust-like particles, and of more and of less liquid 

 or watery parts which are less complex in chemical 

 nature than are proteids. Some of the visible granules 

 and invisible liquids present in protoplasm are being 

 built up to the proteid stage of elaboration, whilst some 

 are steps in degradation and decomposition. We have 

 no reason to suppose that the molecules of any proteid 

 known at present to the chemist really are the highest 

 degree of chemical complexity attained to in living 

 protoplasm. Probably there is present a further stage 

 of elaboration, a chemical body even more complex than 

 is " proteid," which is continually attracting the lower 

 chemical compounds to itself and as continually break- 

 ing down. This is the ultimate chemical substance of 

 life. It is hidden invisibly in the protoplasm, yet all the 

 chemical changes which go on in the protoplasm of a 

 cell are either leading up to this supreme life-stuff or are 

 leading downwards from it. This ultimate compound, 

 which we suppose to exist but have not demonstrated, 

 has been called " plasmogen." It is this body in which 

 resides the peculiar property of living matter, namely, 

 that of attracting to itself substances containing the so- 

 called " organic " elements carbon, oxygen, hydrogen, 

 and nitrogen and of acting on them in such a way 

 that they " nourish " it that is to say, combine chemically 

 with it to form more " plasmogen." 



The intermediate steps leading up to plasmogen and 

 the products arising from its incessant breaking down 

 are formed under the influence of this unique chemical 

 body, and by it alone. Chemists have not yet succeeded 

 in making them ; only the less elaborate kinds have 

 been "artificially" constructed without the aid of the 



