OCTOBER 22, 1897. ] 
the other that they cannot, be explained 
as the result of the action of chemico- 
physical forees. For myself, I have always 
felt that while such a controversy, like 
other controversies as I ventured to say 
just now, is useful as a stirring of the 
waters, through which much oxygen is 
brought home to many things and no little 
purification effected, the time for the final 
judgment on the question will not come 
until we shall more clearly understand than 
we do at present what we mean by physical 
and chemical, and may, perhaps, be put off 
until somewhere near the end of all things, 
when we shall know as fully as we ever 
shall what the forces to which we give these 
names can do and what they cannot. Mean- 
while, the great thing is to push forward, 
so far as may be, the chemical analysis of 
the phenomena presented by living beings. 
Hitherto the physiological chemists, or the 
chemical physiologists as perhaps they ought 
rather to be called, have perhaps gone too 
much their own gait, and have seemed to 
be constructing too much a kind of chemis- 
try of their own. But that, may I say, has 
in part been so because they did not receive 
from their distinctly chemical brethren the 
help of which they wereinneed. May I go 
so far as to say that to us physiologists 
these our brethren seemed to be lagging 
somewhat behind, at least along those lines 
of their science which directly told on our 
inquiries? That is, however, no longer the 
ease. They are producing work and giv- 
ing us ideas which we can carry straight 
into physiological problems. The remark- 
able work of Emil Fischer on sugars, one 
of the bright results of my period of thirteen 
years, may fully be regarded as opening up 
a new era in the physiology of the carbohy- 
drates; opening up a new era because it has 
shown us the way how to invesigate physio- 
logical problems on purely and distinctively 
chemical lines. Not in the carbohydrates 
only, but in all directions our younger in- 
SCIENCE. 
607 
vestigators are treating the old problems by 
the new chemical methods; the old physio- 
logical chemistry is passing away ; nowhere, 
perhaps, is the outlook more promising than 
in this direction ; and we may at any time 
receive the news that the stubborn old 
fortress of the proteids has succumbed to 
the new attack. 
Another marked feature of the period 
has been the increasing attention given to 
the study of the lower forms of life, using 
their simpler structures and more diffuse 
phenomena to elucidate the more general 
properties of living matter. During the 
greater part of the present century physiol- 
ogists have, as a rule, chosen as subjects of 
their observations almost exclusively the 
vertebrata; by far the larger part of the re- 
sults obtained during this time have been 
gained by inquiries restricted to some halfa 
dozen kinds of backboned animals ; the frog 
and the myograph, the dog and the kymo- 
graph, have almost seemed the alpha and 
the omega of the science. This has been 
made a reproach by some, but, I cannot 
help thinking, unjustly. Physiology is, in 
its broad meaning, the unravelling of the 
potentialities of things in the conditions 
which we callliving. Inthe higher animals 
the evolution by differentiation has brought 
these potentialities, so to speak, near the 
surface, or even laid them bare as actual 
properties capable of being grasped. In 
the lower animals they still lie deep buried 
in primeval sameness; and we may grope 
among them in vain unless we have a 
clue furnished by the study of the higher 
animal. This truth seems to have been early 
recognized during the progress of the science. 
In the old time, observers such as Spal- 
lanzani, with but a moderate amount of ac- 
cumulated knowledge behind them, and a 
host of problems before them, with but few 
lines of inquiry as yet definitely laid down, 
were free to choose the subjects of their in- 
vestigation where they pleased, and in the 
