REPORT OF FHIRTEENTH ANNUAL MEETING. In7 
It-is a general rule that in the body the components tend 
to be distributed among a large number of nerves in a more or 
less: segmental way, while in the head they tend to be concen- 
trated into a few pathways, or only one, into the brain, an adap- 
tation which presents obvious advantages for the simplification 
and unification of the secondary reflex paths from these primary 
centers. 
Now, the central nervous system is, as we have already seen, 
primarily a mechanism to facilitate the reaction of the animal 
to impressions from without, in other words, to put the body in 
correspondence with the environment. Its structure is directly 
determined by the avenues of sense through which these stimuli 
come in and by the character of the responses to these stimuli 
which are necessary for the conservation of the organism. In 
view of the fact that we already possess a detailed know ledge of 
these peripheral nervous pathways, it is manifest that we have here 
a most favorable avenue of approach in an analysis of the incon- 
ceivable complexity of cerebral structure. 
We must know in detail the possible reflex pathways in the 
brain for all olfactory, visual, gustatory responses, etc., in the 
vertebrate type, and then on the basis of such a functional sub- 
division of the brain the problem of the mechanisms of higher 
cerebral processes may be attacked with a reasonable hope of suc- 
cess. The investigation of the internal organization of the brain 
may be pursued in several ways: 
I. The direct study of the human brain, both normal and 
pathological. On account of the enormous practical importance 
of neurology to both human psychology and pathology, research 
naturally turned directly to the human brain; but a more unfavor- 
able starting point could not be found. 
Il. It is now generally recognized that the complex human 
brain can best be understood by finding first a simpler pattern 
such as is presented by one of the lowest vertebrates. Accord- 
ingly the phyletic method has dominated all recent neurological 
research. The brains of individual species are studied and mono- 
graphed, particular attention being paid to the lower members of 
the vertebrate series in the hope of finding in them a schema or 
paradigm which can be followed upward through the comparative 
anatomical series and, after comparison with the ontogeny of 
higher brains, lead to a reconstruction of the phylogenetic history 
of the brain. While this method has been of great service, espe- 
cially to such problems as can be approached from the study of 
external morphology, it is immensely difficult when applied to the 
histological problems, and as a matter of fact has not as yet taken 
us very far. 
