THE PROBLEM OF PATTERN 9 
basis of arrangement and order resulting from the inter- 
action of the hypothetical protoplasmic entities, deter- 
minants, pangenes, or whatever we choose to call 
them, is not only more extremely speculative but fails 
completely as a mechanistic hypothesis. To account 
adequately in any such terms for the uniformity, defi- 
niteness, and constancy of organismic pattern requires 
the further postulation of something very closely resem- 
bling the ordering and integrating principle of the 
Vitalists. And finally, even though we invoke the aid 
of variation and natural selection at every step, as 
Weismann has done, our increasing knowledge of the 
facts of adaptation and of the amazing variety and 
delicacy of regulatory response to environmental con- 
ditions present always new difficulties to the pre- 
formistic interpretation. 
Turning to the other mechanistic alternative, the 
imposition of organismic pattern upon protoplasm 
through its relations with the external world, it is clearly 
necessary for any adequate conception first, that we 
know something of the fundamental nature of organismic 
pattern, and second, that we determine, experimentally 
if possible, how such pattern originates in the relations 
between protoplasm and its environment. One of the 
most striking aspects of organismic pattern, to which 
attention has already been called (see p. 8), viz., the 
similarity as regards various of the more general features 
in different protoplasms indicates that such pattern, at 
least as regards these features, cannot be very closely 
associated with the specific differences in the proto- 
plasms of different species or groups and suggests the 
possibility that it may be primarily quantitative in 
