INSULIN 3
German investigator, prepared an alcoholic extract that was capable of
removing certain of the symptoms of diabetes in laboratory animals
and also in man. He showed that this extract could, for example, be
used as an antidote for the hyperglycemia that is produced by epi-
nephrin. Six patients with clinical cases were also treated with
Zuelzer's extract. Several of them showed favorable results. Most of
the symptoms of diabetes were temporarily removed, glycosuria and
acetonuria particularly. The subjective condition of several of the
~~~t ~ patients was also definitely improved, but, unfortunately, in other cases
toxic symptoms supervened, so alarming in their nature, that the treat-
ment was abandoned. The subject seemed to be closed by the unfa-
vorable results published by Forschback from Minkowski's clinic, and
as a result clinical interest in pancreatic extracts almost entirely dis-
appeared, and the possibility that an internal pancreatic secretion might
exist came to be the problem of the experimentalists. Among these
were Knowlton and Starling who, about 1912, succeeded in showing
that the addition of pancreatic extract to the fluid perfused through
the isolated heart removed from diabetic animals is capable of increas-
ing to some extent the power to utilize sugar. Such results were not
obtained in a sufficient number of experiments, however, to make them
convincing.
The work then came to this country. Stimulated by Knowlton and
Starling's reports, Murlin, Kramer, E. L. Scott and Kleiner took up
the problem, each of them attempting to solve it by preparing extracts
of the pancreas, by various methods, and studying their effects on dia-
betic (depancreatized) animals. These investigators made the fatal
mistake of observing only one symptom of diabetes at a time, instead
r of observing two symptoms, and I believe that had they insisted on this
criterion they would have been sufficiently convinced from their results
that they really had demonstrated the hormone, that they would not
have abandoned their researches.
The most important of all the work that was done in this country
was probably that of Clark, then working under Prof. W. G. McCal-
lum in the pathologic laboratory at Johns Hopkins. Clark made investi-
gations on the effect of transfusing a saline solution through the pan-
creas and then through the heart. He found that if he transfused
Locke's solution containing sugar through the heart before sending it
through the pancreas that the rate of sugar consumption was relatively
slow. If, on the other hand, he transfused this solution first through the