134 SECTIONAL ADDRESSES. 
iraining to the actual problems before him, first, a wholesome reminder 
of the limits of his knowledge and its clarity, and, second, new clues 
towards its advance, and that by no means only in a familiar or an 
expected direction. The stimulus of practical need here, as so often 
in experience, advanced the growth of knowledge beyond the point 
of immediate application to practice. Those who studied to find the 
best and most practical means of saving life threatened by severe 
hemorrhage, or by the shock of wounds or operation, found in the 
course of meeting the immediate emergencies almost endless promptings 
to further inquiries, to be followed then or later—inquiries into the 
physical, chemical, or biological qualities of the blood, into its relations 
to the vessel walls, and into the functional changes of the capillary 
blood system and the factors affecting or controlling them. Those 
who fixed their attention upon the damage wrought in the respiratory 
organs by poison gases were led to many new studies of the funda- 
mental physiology of the lungs. The lymphatic system of drainage 
of the lungs was re-examined, and wide new experimental studies of 
the modes of regulation of the breathing were undertaken which have 
thrown new and valuable light upon the normal mechanisms of respira- 
tion. An inquiry into the poisonous action of the high-explosive tri- 
nitrotoluene, and into the possibility that slightly abnormal forms of 
this substance, found as a small contamination of the normal form, 
might be specially toxic, led to a clear negative answer. But it led 
unexpectedly, it is both curious and useful to note, to the discovery 
that one of these abnormal forms was an effective reagent in the 
laboratory. By its means the chemical structure of a constituent of 
muscle substance known as carnosin was for the first time determined, 
and carnosin has now been synthesised artificially from simple materials. 
In sum, then, we may gratefully recognise that the War in its 
horror and waste has not brought evil without any admixture at all 
of good. We may be encouraged at least to hope that the active co- 
operation which the War established and fostered in diverse ways 
between the physiologist and the medical or surgical clinician may 
remain to bring lasting good, on the one side to the cause of learning 
and its advance, and on the other to medical education and to medical 
progress. 
11 Ol 
If we have thus looked backward to the development of physiology 
in the past half-century, and to the influence upon its course which 
the War has brought about, I would invite you to look forward to the 
future and to review the aims of physiology and the boundaries to 
which it should properly extend in its relations to other subjects of 
study. 
Foster, early in his work at Cambridge, spoke of physiology as 
being the study of the differences between the living body and the 
dead body. The progress of this study, as it has been carried on during 
the past generation, may be considered from two directly opposite 
points of view. Viewed in one way, we may think of this progress as 
being a progress in analysis, as a disentanglement of the diverse though 
not separable functions of the body and of each of its parts. Viewed 
ee a ee 
