654 TRANSACTIONS OF SECTION I. 
the milieu in which vital processes progress, but, notwithstanding the stimulat- 
ing work of Graham, the pure chemist of the last century consistently left 
colloids on one side with a shudder of distaste. Again, we have come to 
recognise that the insidious influence of catalysts is responsible for all chemical 
change as it occurs in living matter, but for many years after Berzelius the 
organic chemist gave to the subject of catalysis very cursory attention, funda- 
mental though it be. Lastly, every physiological chemist has to realise that 
among his basal needs is that of accurate methods for the estimation of organic 
substances when they are present in complex mixtures. But the organic chemist 
of the nineteenth century did not develop the art of analysis on these lines. Of 
the myriad substances, natural or artificial, known to him at the most a few 
score could be separated quantitatively from mixtures, or estimated with any 
accuracy. It was a professional or commercial call rather than scientific need 
which evolved such processes as were available, so that this side of chemical 
activity developed only on limited and special lines. 
All these circumstances were, of course, inevitable. Organic chemistry in 
Liebig’s Jater years was concerned with laying its own foundations as a pure 
science, and for the rest of the century with building a giant, self-contained 
edifice upon them. The great business of developing the concepts of molecular 
structure and the wonderful art of synthesis were so absorbing as to leave 
neither leisure nor inclination for extraneous labours. But it is easy to recog- 
nise that, near the beginning of the present century, a sense of satiety had 
arisen in connection with synthetic studies carried out for their own sake. 
Workers came to feel that, so far as the fundamental theoretical aspects of 
chemistry were concerned, that particular side of organic work had played its 
part. In numerous centres, instead of only in a few, quite other aspects of the 
science were taken up: in particular, the study of the dynamic side of its 
phenomena. The historian will come to recognise that a considerable revolution 
in the chemical mind coincided roughly with the beginning of this century. 
Among the branches which are fated to benefit by this revolution—it is to be 
hoped in this country as well as others—is the chemistry of the animal. 
But I would like to say that I do not find, on reading the contributions to 
science of those who, as professed physiological chemists, ploughed lonely 
furrows in the last century, any justification for the belief that the work done 
by them was amateurish or inexact; no suggestion that anything inherent in 
the subject is prone to Jead to faults of the kind. Truly these workers had to 
share ignorance which was universal, and sometimes, compelled by the urgency 
of certain problems, had perforce to do their best in regions that were dark. 
But they knew their limitations here as well as their critics did, and relied for 
their justification upon the application of their results, which was often not 
understood at all by their critics. 
There is little doubt, for instance, that it was the earlier attempts of various 
workers to fractionate complex colloid mixtures that led to the cynical state- 
ment that ‘ Thierchemie is Schmierchemie.’ But the work thus done, even such 
work as Kihne’s upon the albumoses and peptones, had important bearings, and 
led indirectly to the acquirement of facts of great importance to physiology and 
pathology. 
In connection with enzyme catalysis the work done at this time by physio- 
logical chemists was in the main of a pioneer character, but it was urgently 
called for and had most useful applications. By the end of the century, indeed, 
it had become of great importance. I recall an incident which illustrates the 
need of suspended iudgment before work done in new regions is assumed to be 
inexact. In 1885 E. Schiitz published a study of the hydrolysis of protein by 
pepsin which showed that the rate of action of the ferment is proportionate to 
the square root of its concentration. When this paper was dealt with in 
Maly’s ‘ Jahresbericht’ the abstractor (who from internal evidence I believe was 
Richard Maly himself) believed so little in such an apparent departure from the 
laws of mass action that he saw fit to deal with the paper in a ribald spirit and 
to add, as a footnote to his abstract, the lines : 
‘Musst mir meine Erde 
Doch lassen steh’n 
Und meine Hiitte die du nicht gebaut!’ 
