before a complete study which will necessarily require mnuch
time and expense is undertaken.
The exact significance of insulin in diabetic tissues is not
known at present. We have made the obvious suggestion that
the insulin must be present in a comparatively unavailable form.
This is the only explanation, unless the generally accepted con-
ception of the significance of the persistently low respiratory
quotient in diabetic animals is doubted.
We have recently attempted to analyze the tissues of dogs
thoroughly poisoned with phloridzin. Very little can be stated
concerning these results as yet, but it appears that insulin is
present in normal amounts in the pancreas and in demonstrable
amounts, at least, in other tissues.
The bearing these results will have on the islets of Langer-
hans theory of diabetes remains to be determined. Althongh the
great mass of pathological and physiological evidence supports
this theory it has been vigorously attacked recently by Oertel
(30) and by Vincent (31). These writers review work. mainly
pathological, which leads them to the conclusion that the islets
are not separate and distinct structures but are temporarily
nodified portions of the secretory tubules of the pancreas.
THE INSULIN-LIKE MATERIAL IN PLANTS
The literature dealing with the insulin-like material in
plants has been briefly reviewed eksewhere (32). MIacleod (33)
points out that care should be exercised in considering tlhese
results since hypoglycemia may be caused by certaiii clihemicals,
hy lowered blood pressure, by injury to the liver, or by stimula-
tion of the pancreas. Stress has been laid on the delayed action
of vegetable extracts by Collip and others. We submit curves
showing the relative speed of action of a purified sample of vege-
table extract as compared to that of an average (lose of pan-
creatic insulin. In each of the three experiments the blood sugar
had returned to its previous level by twelve hours after the time
of the last determination shown on the 'chart.
You will observe that the beetroot extract exerts its effects
on blood sugar as rapidly as insulin. The latter part of the
experiment was conducted in the same manner as the early
experiments by the Toronto group (34) when the effect of
insulin on glycogen formation in diabetic dogs was being studied.