426 SECTIONAL TRANSACTIONS.—1. 
The results are considered to support the view that the internal secretion of the 
thyroid is a compound of thyroxin with some other radical which considerably 
increases its activity. 
6. Prof. H. C. Bazerr.—aperimental Aortic Regurgitation in 
Animals. 
X-rays and electrocardiographs and also some blood pressure readings have 
been taken on dogs with chronic aortic regurgitation. ‘The outstanding result 
has been that after the operation the heart shadow is diminished in size. Where 
dilatation has been seen the animal has died immediately. There appears to be 
a diminution in the size of the right ventricle, with only a relatively slight 
increase in the left. Within a few weeks the heart is definitely larger, but at 
death there has been only slight hypertrophy, even when the animal has exer- 
cised daily for a month. The appearance has been more that of a chronic 
mild dilatation with lengthening of the fibres. No striking electrocardiographic 
changes were found. 
Systolic blood pressure in the femoral above those of the brachial or carotid 
were readily obtained. Animal experiments and some with a schema suggest 
that this is due to the kinetic energy of the blood, which is greater in the 
lower extremities than in the upper. 
7. Dr. R. Domincuez.—Observations by a Clinical Method over long 
periods on the Blood Pressure of Rabbits under various Physio- 
logical and Pathological Conditions. 
The determination of the blood pressure in the intact animal is recognised 
to be important. The ideal method should be simple in application, should 
involve the least manipulation of the animal, and should allow frequent and 
numerous observations. These requirements are met by Van Leersum’s method, 
as employed by us. Rabbits are used. The carotid artery is exposed, dis- 
sected, and then surrounded by a cutaneous flap. In this way a loop is made, 
around which a cuff, connected to a Riva-Rocci manometer, is applied, and 
then readings obtained by palpation. The animal is placed in a box and its 
head raised by means of a ring so as to expose the loop. Observations have 
been made on excitement, struggle, digestion, inanition for reasonable intervals, 
temperature, copulation, small doses of morphin, such pathological conditions 
as naturally arise in a laboratory, and the effect of double adrenalectomy. I 
have been unable to confirm the alleged ‘hypertension’ of experimental 
cholesteatosis. 
8. Dr. A. C. Ivy, Dr. R. K. 8. Lim, and Dr. J. E. McCarruy.—The 
Genesis of the Second Phase of Gastric Secretion. 
The second phase of gastric secretion may be further subdivided into gastric 
(Pavlov) and intestinal phases (Pavlov, Ivy). 
Gastric Phase-—We have found, contrary to Pavlov, that local mechanical 
stimulation of the stomach causes secretion. The effective stimulus is a sudden 
distension, or, if slowly induced, a distension which eventually induces motility, 
such as occurs after a more rapid inflation. 'The mechanical effect is abolished 
by fat in the intestine, and to a less degree by fat in the stomach; it is com- 
pletely prevented by atropine (subcutaneously). Since an increase of 200 c.c. 
in the gastric volume causes secretion, it was possible that previous observations 
on chemical or secretagogue stimulation might have been due to the mechanical 
factor alone, especially as the quantities employed were rarely less than this 
amount. Applications of raw meat, meat juice, glucose, B-alanine, and hista- 
mine in 20-c.c. amounts confirm the existence of a chemical factor. 
Intestinal Phase.—In a dog with the whole stomach formed into a pouch 
(the vagi being cut) and the duodenum anastomosed to the esophagus, the feeding - 
with water, milk, meat, bread, B-alanine or histamine (which naturally pro- 
ceeds directly into the intestine), all cause secretion in the isolated stomach. 
Atropine and fat irhibit this secretion. 
Mechanism.—Transfusion of fed blood to unfed Pavlov pouch dogs has no 
influence on gastric secretion. In similar animals, cross-cireulated by 
