258 Ke FE AI CORTSE [ocroBER 
eye-spots may be induced to grow if steps be taken to initiate the 
changes. Here we have evidence as to how the inherent power of the 
organism—not the cells—may respond in a definite direction to fulfil 
its requirements. 
In the evolution of the nervous system we must recognise two 
stages of development, the one gradually merging into the other. As 
Wilson says in his “ Zoology”: “In the lower or invertebrate forms 
of life, the nervous apparatus may be considered to be almost wholly — 
occupied in the reception of the ordinary sensations which minister to 
the wants and necessities of existence, without any active or intelligent 
appreciation of the causes or results of the sensations thus conveyed. 
In the Vertebrata, on the other hand, we find the higher perfection 
of the correlative apparatus associated with powers which place the 
organism far above the rank and relations of a piece of automatic 
mechanism.” We accordingly notice this specialisation of the cor- 
relative powers in these higher forms, evincing itself in the possession 
of a power of appreciation of the origin of sensations known as “ in- 
telligence” ; whilst, in virtue of this latter feature, we find another 
and distinctive power superadded, which is devoted to the regulation 
of the movements of the body, and which is known as the power of 
“volition” or “ will.’ Now, it is the possession of these varied and 
distinctive features, due in the lower orders to reflex nerve action, and 
in the higher to a species of intelligence, that led Lamarck to denote 
as needs, wants, or desires the processes through which animals satisfy 
the physical wants of their bodies. For whilst, in the lower, that 
process by which the exigencies of the organism are satisfied, may be 
considered as in response to a need, as in the vegetable world; in the 
higher, a species of will is manifested, as the will for food, ete., and 
this may certainly be construed as a desire. 
Professor Conklin, in an able article on the factors of organic 
evolution (in “Footnotes of Evolution,’ by Professor Jordan), has 
arrived at some inconclusive deductions, under the head “ Use and 
Disuse.” He remarks: “I take an example which will serve as an 
illustration of a whole class. Jackson says that the elongated siphon 
of Mya, the long-necked clam, is due to the habit of burrowing in the 
mud; or, to quote his own words, ‘It seems very evident that the 
long siphon of this genus was brought about by the effort to reach 
the surface induced by the habit of deep burial.” It certainly would 
be pertinent to inquire (asks Professor Conklin) where it got this 
habit, and how it happened to be transmitted. It is surely as difficult 
to explain the acquisition and inheritance of habits, the basis of which 
we do not know, as it is to explain the acquisition and inheritance of 
structure which are tangible and visible.” That Professor Conklin 
does not understand the acquisition of habits shows clearly that he 
does not understand Lamarck. I have already in these pages explained 
my interpretation of the nature of functions, but my point may 
