tzZ2 Cc. M. CHILD 
at its beginning, no adequate basis for ‘vitalistic’ interpretations 
of regulatory phenomena finds but little satisfaction or enlighten- 
ment in Driesch’s ‘entelechy’ or in other assumptions of the neo- 
vitalistic school. 
In the present state of our knowledge these views are and must 
remain expressions of personal opinion. Driesch’s first two ‘Be- 
weise der Autonomie der Lebensvorgange”’ (Driesch, ’01, ’03 etc.), 
which are based on certain phenomena of form regulation, con- 
stitute proofs only when we accept Driesch’s premises, and as I 
have pointed out (Child, ’08b) these premises are pure assump- 
tions. Neither Driesch nor anyone else has placed them on a 
foundation of fact. The existence of the ‘harmonious-equipo- 
tential system,’ for example, which is of so great importance to 
Driesch, is a matter of assumption, not of fact. So far as the sys- 
tems, which according to Driesch belong in this category, have 
been thoroughly examined, they have shown themselves to be 
neither harmonious nor equipotential in Driesch’s sense, and to 
the extent which he has assumed. It is of course easy to assume, 
as Driesch has done, that the harmony of these systems is due to 
entelechy and their limitations to physico-chemical factors, but 
such assumptions, since they are so manifestly invented ad hoc, 
do not carry conviction to the minds of most biologists, what 
ever, their effect upon their author. 
Much the same is true of other modern vitalistic hypotheses: 
as expressions of personal opinion, they are of great interest in 
the history of scientific thought, but none of them thus far has 
presented any convincing arguments in its own support. 
Furthermore, with the exception of Driesch’s analytical con- 
sideration of the regulatory phenomena in organisms, most of 
the recent published works of general character, which concern 
themselves primarily with the regulations which involve the 
visible morphological features of the organism, e. g., the books of 
Morgan (’07), Korschelt (’07) and Przibram (’09), have been de- 
voted chiefly to the descriptive, rather than the analytical and in- 
terpretative aspects of the subject. 
In view of these facts, an attempt at physiological analysis of 
the regulatory processes or of some of them can scarcely be re- 
