20 
equivalent to, and is in fact, an elementary form of the function performed 
in higher animals by muscle, though the higher type of muscle structure 
is not recognisable. 
But it is easily conceivable that the first advance towards speciality of 
structure in a homogeneous protoplasm may be effected by a change in 
the molecular state of matter, without attaining to such definition of parts 
as would satisfy our idea of a specialised apparatus.- Such a change of 
atomic arrangement may also, if permanently induced, supply a basis for 
further evolution, and finally, positive structural differentiation. Thus, 
then, we may fairly admit that organ and function grow pari passu from 
the nascent to the matured state, neither being the antecedent, but both 
due to pre-existing condition of organic matter and the operation of special 
external influences. Strictly speaking, however, we cannot use the terms 
"organ" and "function" in so simple a case as that under our notice, 
but must view it rather as a readjustment of the organic action correspond- 
ing with a rearrangement of the organic atoms. 
Now the question immediately arises— How is this change initiated ! 
and how maintained? Physiologists have answered these questions by 
inventing a term which expresses the fact rather than the cause— namely, 
"vital action." To initiate and support this vital action, a force, "sui 
generis " and independent of material agencies is pre-supposed. There are, 
I think, good : reasons for rejecting the broad assertion, that all organic 
change is due to a vital force, if we are therewith required to believe that 
this force is not the exponent of some physical or chemical reaction in 
organic atoms. Of life, we know nothing apart from matter, but we do 
know that the elements of which living matter is composed, are chemically 
identical yet exhibit different properties, and that while they exhibit these 
different properties, their chemical constitution remains identical. The 
properties of albumen, fibrin, &c, are in fact preserved only so long as 
they remain undecomposed. 
Chemical change is consequently not the source of the properties of 
matter, but rather of change in the behaviour of these properties — i. e. 
potential changed into actual energy at the cost of the material concerned, 
and, in so far, therefore, implies dissolution rather than preservation of 
matter. On the other hand, the physical constitution of organic atoms 
may be conceived to be capable of re- arrangement without chemical change, 
and of alteration in property without decay, so that apart from any hypo- 
thesis of vital force, the properties of organic matter, as known to us at 
present, may be simply considered the expression of physical peculiarity 
