182 C. M. CHILD 
separated from the others in the final analysis, but in its extreme 
forms each type is readily distinguishable. 
The physiological correlative effect of a part upon others is 
then the result of all that that part is and has been in the past, of 
its physical and chemical constitution, its position, its relation to 
external factors and of the changes which are occurring in it. It 
is apparent that there exists in physiological correlation the possi- 
bility of an almost infinite variety and specificity. Driesch (09) 
has recently maintained that the specificity of the ‘Restitutions- 
reiz’ together with the specificity of the reaction to it constitute’ 
an ‘Individualitit der Zuordnung’ which is inexplicable on a 
physico-chemical basis and which therefore constitutes a new and 
independent ‘proof’? of the ‘Autonomie der Lebensvorgiinge.’ 
Comment seems scarcely necessary. One sees here merely an 
assertion, a jump at conclusions, but n0 proof, where proof of 
the most convincing character is absolutely essential. If vitalism 
can present no more convincing arguments than this its future 
prospects in science are not bright. 
THE NATURE OF REGULATION 
1. Organic or physiological equilibrium and equilibration 
One of the most characteristic features of organisms is,as Roux 
(95, I, pp. 145, 154, 392, etc.) has said, their continued existence 
as individuals, their ‘Dauerfihigkeit’ amid changing internal and 
external conditions. On the other hand this ‘Dauerfahigkeit’ 
is only relative, not absolute, 7. e., itis limited. The organism is 
constantly changing, and-so far as our knowledge goes, never twice 
the same, yet the continuity of individuality is obvious. 
Nevertheless the continuity of the existence of individuality 
must not be emphasized to the exclusion of the fact that under 
certain conditions this individuality may disappear, at least in the 
simpler organisms, and be replaced by other individualities in 
larger or smaller number. Certain factors concerned in this physi- 
ological disintegration will be discussed below, but for the pres- 
ent we are concerned with the individual, the system as we see it 
