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Proceedings of the Royal Society of Edinburgh. [Sess. 
XV. — Preliminary Communication on the Effects of Thyroid- 
Feeding upon the Pancreas. By Dr M. Kojima, Staff-Surgeon 
Imperial Japanese Navy. Communicated by Sir Edward A. 
Schafer, F.R.S. (With Two Plates.) 
(MS. received July 3, 1916. Read July 3, 1916.) 
In the course of a systematic inquiry, conducted in the Physiology Depart- 
ment of Edinburgh University, into the morphological and physiological 
changes produced in animals by thyroidectomy and thyroid-feeding — 
especially in rats — certain striking morphogenetic changes in the pancreas 
have come under observation. The full results of the investigations of 
which these observations form a part will be published subsequently, but 
it has been thought well to bring the effects herein described before the 
notice of this Society without waiting for the completion of every part of 
the investigation. 
The morphogenetic changes produced in the pancreas by thyroid-feeding 
are of two kinds. The first is the causation of division and multiplication 
of the gland-cells, so that, after a few days’ feeding with an adequate 
amount of thyroid, evidences of karyokinesis are observable in the shape 
of numerous mitoses at various stages, occurring so frequently that there 
may be as many as ten or twelve within the field of the ordinary high- 
power microscope. This is well seen in fig. 1, which is a drawing of a 
portion of such a field from the pancreas of a rat which had been fed for 
seven days with ordinal food, plus 1 grm. dried ox-thyroid per day. In 
this small portion of pancreas as many as ten nuclei in various stages of 
karyokinesis can easily be made out. This section was stained by Muir’s 
method (alcoholic eosin and methylene blue) : heematoxylin-stained pre- 
parations exhibit the mitoses equally well. Fig. 2 is from a control 
animal which received no thyroid with its food. It is of course a 
section of normal pancreas, in which, as is well known, mitoses are 
entirely absent. The change described begins to appear in rats after 
about three days’ feeding, and continues for about ten days, after which 
time mitoses are fewer in number, and eventually disappear in spite of 
continuous feeding. The cells become after a time more numerous and 
smaller, but if the feeding be continued they again increase in size, the 
whole gland becoming enlarged and eventually resuming its normal 
microscopic appearance. After feeding for three days and subsequent 
