+ 
1895.] Development of Vegetable Physiology. 391 
Linnzus, and even down to within the last fifty years, would 
have called the products of the v/s vitalis. It desires to know 
what the specific energies of the plant are capable of accom- 
plishing, in short, what is going on within the plant in the 
way of life processes. As will be readily seen, the whole 
matter is summed up in an exhibition of energy, which in 
former days was called vital energy, and thought to reside 
exclusively in living organisms, but now held to be only a 
special manifestation of the general physical forces of the uni- 
verse. 
The energies of plants fall into two categories, those which 
bring about changes in the intimate structure of vegetable 
substances, and those which bring about movement; and 
hence we call physiology a superstructure whose foundation 
is chemistry and physics. The present great advance in the 
science may, in large measure, be traced to the wonderful 
advances in the sciences of chemistry and physics, which have 
supplied facts and methods to assist the physiologist in his 
study of life processes. 
_ Yet it would be an egregious mistake to suppose that phys- 
iology is but a dependency of chemistry and physics. The 
substitution of the so-called mechanical philosophy of life for 
the old vitalistic philosophy has not in any way rendered 
the vital activities less wonderful, or the protoplasmic display 
of energy less complex, less inscrutable, or less suz generis. 
The meaning of the word life shows no likelihood of being 
solved until the chemical and physical constitution of the 
protoplasmic molecule is understood, and that is too far away 
to make speculation at this time worth while; and so we need 
not quarrel with those who fancy that even when that ad- 
vanced goal is reached the problem will not be solved, but a 
mysterious residuum will still exist to endow protoplasm with 
autonomy. Be that as it may, the path of present advance- 
ment keeps steadily onward in the clear light of physical laws, 
and ignores the nearness of mystical, unfathomable shadows. 
_ But returning from this long digression in separating phys- 
lology into the three reasonably distinct sciences—caliology, 
ecology, and physiology proper—we will proceed with the 
inquiry regarding the present scientific status and its course of 
attainment in each of the three branches. It is not, however, 
any part of my purpose to give a philosophical or historical dis- 
quisition upon the subject, but merely to point out a few land- 
