At this stage of the investigation, we secured the services of Dr.
Collip, Professor of Biochemistry at Edmonton University on a year's
leave of absence. He has worked intensively and has now obtained a
very potent, soluble protein free extract which is being tested clinically.
Previous to this we had anaesthetized and connected a diabetic dog
to a blood pressure recorder. It was found that the protein containing
extract had a temporary but marked depressor effect. Samples of
blood were taken every half hour during the experiment and it was
found incidentally that the percentage of blood sugar fell but slightly
followinfig the injection of.a known, potent extract. This fact may, in
part, account for the failures of some observers to obtain results.
The question now arose as to why the extract acted but slightly under
anaesthesia. It seemed reasonable to suspect that the glycogenetic
function of the liver was in some way involved as glycogen is notbuilt
up during anaesthesia. We cannot state definitely, but some of our
results would lead us to believe that the presence of the internal secretion
of the pancreas is necessary in order that the liver build up glycogen
Dog 19 was our first attempt to keep a depancreatinised animal alive
with artificially administered internal secretion of the pancreas. This
_ dog lived 19 days. Our next attempt was on dog 27; this dog lived
21 days and death was caused by an anaphylactic-like reaction following
an injection of calf extract. When dog 27 died, we were using dog 33
as a trial dog for the effects of the various forms of extract. This dog
has been given almost every variety of extract we had prepared and
by every method of administration. We had from time to time given
therapeutic doses of extract, and at the end of 20 days, the dog was in
excellent condition. We then converted her into a longevity experiment.
A dose of extract was given twice per day, and later once per day, and
the animal was fed on lean meat, milk and dog biscuits. A slight gain
in weight was noted. At the end of 70 days, the dog was becoming
thinner and weaker but was still able to walk and wag her tail. The
animal was then chloroformed and an autopsy performed by Dr. Robin-
son. No Islet tissue whatever was found. However, in the submucous
layer of the intestine, there was a nodule of acinous tissue about 2 mm.
in diameter (serial section of this failed to reveal islet tissue.) Thus, we
believe that, under favourable conditons, a totally diabetic dog may be
kept alive for a considerable length of time if the internal secretion of
the pancreas is administered.
In order to prove that this substance is only found in the pancreas,
controls were done with extracts of spleen, liver, thymus, muscle and
thyroid.- Thyroid extract alone gave a slight fall in blood sugar.
At the present time, Mr. Best and Dr. Hepburn are conducting
experiments on the respiratory quotient. Their results, though not
sufficient in number as yet to report, strongly'indicate that carbohydrate