Herrick, Nerve Components. 309 
So the other sensori-motor systems may be severally inves- 
tigated, beginning the attack in each case with some species 
low down in the, vertebrate series in which this particular 
mechanism is highly developed, and then extending the re- 
search to higher and lower types. 
We may ultimately hope for a subdivision of the brain 
which shall be both structural and functional, each organ or 
pathway being given its function or meaning in the system as a 
part of the machinery of keeping the body in vital, helpful 
contact with environing forces. The great morphological 
‘thead problems,’ such as the primitive metamerism and the 
subsequent marvelous kalaidoscopic changes in structure and 
function of the component segments, these must all be read 
through the medium of such an intensive study of these factors 
upon which all differentiation has in last analysis depended. 
There is another point of view from which I have been 
somewhat interested to develop the implications of the doctrine 
of nerve components, that of scientific methology in general. 
It is said that scientific explanation consists essentially in 
such an organization of facts that they may be generalized or 
included under certain laws or uniformities which permit a fore- 
casting of future events. Now, without going into an exposi- 
tion at this time of the implied philosophy of nature, I think 
that a little reflection will show that this statement, while true 
in a certain limited sense, is very defective. 
What is the nature of this organization of facts from which 
so great benefits are expected to flow? Can it in last analysis 
be anything other than the correlation of experience? All of 
the ‘‘facts’” with which we deal have grown up in experience; 
they are in a literal sense the products of our experience. As 
men of science we have nothing to do with ‘‘things-in-them- 
’ only with phenomena, out of which we have con- 
structed by mental process certain objective things which we 
regard as real—‘‘constructs,’’ or in common parlance, objects, 
facts, data. 
selves,’ 
By these things which grew up in experience (we have in 
most cases forgotten how) we measure up and evaluate all new 
