140 The Unity of the Organ ism 



Preliminary Remarks on the Bearing of Physical Chemistry 

 on the Protoplasm Doctrine 



The theory of protoplasm as the living substance, as 

 though there were a single substance identical in all or- 

 ganisms and in ah 1 parts of the same organism, has passed 

 into a new and peculiarly subtle stage during the last two 

 or three decades. This has been one of the results of the 

 application which was sure to be made of physical chemistry 

 to biological phenomena. 



An understanding of what is implied by this will be 

 facilitated by reflecting on some of the most obvious dif- 

 ferences between physics and chemistry, and on what phys- 

 ical chemistry as contrasted with chemistry pure and 

 simple is ; that is, chemistry as it was prior to the rise of 

 physical chemistry. But since we are invading a perilous 

 realm, one in which diverse and strenuously contested views 

 prevail, we must confine ourselves to what is most obvious. 



That that vast series of transformations of natural sub- 

 stances which occur when two or more of the substances 

 come together under certain conditions, so profound that 

 the new substance is wholly different from the originals, are 

 real objective phenomena, and are the bases of the science 

 of chemistry, no one will gainsay however unqualifiedly he 

 may be committed to the theory that these phenomena be- 

 long to the domain of physics after all. The reality of the 

 transformations, and hence the reality of the discrete, in- 

 dividuated bodies or substances, both those entering into the 

 combinations and those arising from the combinations, is 

 what especially concerns us. Whether the combinations and 

 transformations are influenced by physical as contrasted 

 with chemical forces, and what names and classifications 

 shall be employed in dealing with the phenomena, are of 

 very secondary importance to this discussion. 



On the other hand, that there is an almost if not quite 



