606 
urally attract great attention, and give a 
special character to the period. 
In the past thirteen years we may recog- 
nize both these kinds of progress. Of the 
former kind I might take, as an example, 
the time-honored problems of the mechanics 
of the circulation. In spite of the labor 
which has been spent on these in times of 
old, something always remains to be done, 
and the last thirteen years have not been 
idle. The researches of Hurthle and Tiger- 
stedt, of Roy and Adami, not to meation 
others, have left us wiser than we were be- 
fore. So again, with the also old problems 
of muscular contraction, progress, if not 
exciting, has been real ; we are some steps 
measurably nearer understanding what 
is the exact nature of the fundamental 
changes which bring about contraction and 
what are the relations of those changes to 
the structure of muscular fibre. In respect 
to another old problem, too, the beat of the 
heart, we have continued to creep nearer 
and nearer to the full light. Problems 
again, the method of attacking which is of 
more recent origin, such as the nature of 
secretion, and the allied problem of the 
nature of transudation, have engaged at- 
tention and brought about that stirring of 
the waters of controversy which, whatever 
be its effects in other departments of life, 
is never in science wholly a waste of time, 
if indeed it be a waste of time at all, since, 
in matters of science, the tribunal to which 
the combatants of both sides appeal is al- 
ways sure to give a true judgment in the 
end. In the controversy thus arisen, the 
last word has perhaps not yet been said, 
but whether we tend at present to side 
with Heidenhain, who has continued into 
the past thirteen years the brilliant labors 
which were, perhaps, the distinguishing 
features of physiological progress in preced- 
irg periods, and who in his present suffer- 
ings carries with him, I am sure, the sym- 
pathies, if not the hopes, of all his brethren, 
SCIENCE. 
LN. S. Von. VI. No. 147. 
or whether we are more inclined to join 
those who hold different views, we may all 
agree in saying that we have, in 1897, dis- 
tinctly{clearer ideas of why secretion gathers 
in an alveolus or lymph in a lymph space 
than we had in 1884. 
I might multiply such examples of prog- 
ress on more or less old lines until I 
wearied you; but I will try not to do so. 
I wish rather to dwell for afew minutes on 
some of what seems to be the salient new 
features of the period under review. 
One such feature is, I venture to think, 
the development of what may perhaps be 
called the new physiological chemistry. We 
always are, and for a long time have been, 
learning something new about the chemical 
phenomena of living beings. During the 
years preceding those immediately recent, 
great progress, for which we have es- 
pecially, perhaps, to thank Kuthne, was 
made in our knowledge of the bodies which 
we speak of as proteids and their allies. 
But while admitting to the full the high 
value of all these researches, and the great 
light which they threw on many of the ob- 
scurer problems of the chemical changes of 
the body, such, for instance, as the digest- 
ive changes and the clotting of blood, it 
could not but be felt that their range was 
restricted and their value limited. Grant- 
ing the extreme usefulness of being able to 
distinguish bodies though their solution or 
precipitation by means of this or that salt 
or acid, this did not seem to promise to 
throw much light on the all-important 
problem as to what was the connection be- 
tween the chemical constitution of such 
bodies and their work in the economy 
of a living being. For it need not be 
argued that this is an all-important prob- 
lem. ‘To-day, as yesterday and in the days 
before, the mention of the word vitalism or 
its equivalent separates as a war-cry physi- 
ologists into two camps, one contending 
that all the phenomena of life can, and 
