362 THE LIMITS OF NATURAL SELECTION 
life is the cause and not the consequence of organiza- 
tion.” In his celebrated article “On the Physical 
Basis of Life,” however, he maintains, that life is a 
property of protoplasm, and that protoplasm owes its 
properties to the nature and disposition of its molecules. 
Hence ‘he terms it “the matter of life,” and believes 
that all the physical properties of organized beings are 
due to the physical properties of protoplasm. So far 
we might, perhaps, follow him, but he does not stop 
here. He proceeds to bridge over that chasm which 
Professor Tyndall has declared to be “ intellectually 
impassable,” and, by means which he states to be 
logical, arrives at the conclusion, that our “ thoughts 
are the expression of molecular changes in that matter 
of life which is the source of our other vital phenomena.” 
Not having been able to find any clue in Professor 
Husley’s writings, to the steps by which he passes from 
those vital phenomena, which consist only, in their 
last analysis, of movements of particles of matter, to 
those other phenomena which we term thought, sensa- 
tion, or consciousness ; but, knowing that so positive an 
expression of opinion from him will have great weight 
with many persons, I shall endeavour to show, with as 
much brevity as is compatible with clearness, that this 
theory is not only incapable of proof, but is also, as it 
appears to me, inconsistent with accurate conceptions ot 
molecular physics. To do this, and in order further to 
develop my views, I shall have to give a brief sketch 
of the most recent speculations and discoveries, as to 
the ultimate nature and constitution of matter. 
