Significance of Functional Metabolism in the Plant. 101 



process of oxidation occur in the interior of vitally active protoplasm 

 (including the nucleus), as is brought about by even the feeblest 

 form of active oxygen (hydrogen peroxide). This still holds good 

 even if the reactions of active oxygen are obtained in the expressed 

 sap, i.e., after mixing bodies which in the plant are separate. If, 

 however, active oxygen ever plays any part at all, it is at most to be 

 regarded as one only of the means of which the organism avails 

 itself, and not as revealing the true and essential cause of functional 

 metabolism. 



Side by side with the general process of functional metabolism, 

 many other chemical operations must necessarily come into play, in 

 order to provide the various compounds which are formed in the 

 organism, in order to build up its tissues, or otherwise. Although 

 these processes are not of necessity in continuous action, it is difficult 

 to separate them from the general functional metabolism. We are 

 placed with regard to the plant, somewhat in the position of a man 

 who, while he can control the raw material introduced into a factory 

 and the finished products turned out from it, is not permitted to 

 inspect the internal working. Unless the observer has a knowledge 

 of this from other sources, it is simply impossible for him to say 

 what is the nature of all the manifold operations carried on in a 

 chemical factory, whether simultaneously or successively, jointly or 

 separately. At the same time the observer may be quite aware that 

 all work in the factory is impossible if the fire be not burning under 

 the boiler, or if the driving power in general be not available, and he 

 may also know that the gaseous products of combustion, the ashes 

 and the slag, must be got rid of, simply in order to make room for 

 the work to go on. In the factory, however, just as in the plant, the 

 general driving power is not always utilised for the same purposes or 

 with equal efficiency. Indeed, when the steam-engine is at work but 

 the rest of the machinery is out of gear, the whole driving power is 

 wasted. No less is it true, in the case of the plant, that the relation 

 between the available kinetic energy and its utilisation for various 

 purposes, or in other words the economic coefficient, may vary 

 within very wide limits according to the stage of development and 

 the external conditions. 



