194 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



adaptations in physiology without any restriction. The 

 centre acts in one sense or in the other, if stimulated by any 

 temperature beyond a very limited range, and it is in the 

 action of the centre that the " regulation " of heat consists. 1 

 Primary Regulations in the Transport of Materials and 

 Certain Phenomena of Osmotic Pressure. Very similar 

 phenomena of regulation are present in many processes 

 concerned in the whole of metabolism. Let us consider 

 for a moment the migration of materials in plants. When- 

 ever any compound is used at a certain place, a permanent 

 afflux of this compound to that place sets in from 

 all possible directions. No doubt this is a " regulation," 

 but it is also the function itself, and besides that, a very 

 simple function based almost entirely on well-known laws 

 of physical chemistry. And in other cases, as in the ascent 

 of water to the highest tops of our trees, which purely 

 physical forces are said to be insufficient to explain, we can 

 appeal to the unknown organisation of many cells, and there 

 is nothing to prevent our attributing to these cells certain 

 functions which are, if you like to say so, regulatory in 

 themselves. Among other facts of so-called regulations 

 there is the stopping of metabolic processes by an accumula- 

 tion of their products : as, for instance, the transformation of 

 starch into sugar is stopped, if the sugar is not carried 

 away. Of course that is a regulation, but it again is an 

 intrinsic one, and it is one of the characteristics of reversible 

 chemical processes to be stopped in that way. I know very 

 well that in this particular case a certain complication is 



1 The phenomenon of fever we leave out of account here ; it is regarded by 

 some as regulation, by others as a disturbance of heat regulation. Of course, 

 if the first view should ever prove to be the right one, fever might be classified 

 among the real regulations of the secondary type. 



