284 THE INTERNAL SECRETIONS—1920 
angioneurotic edema, could not possibly continue as 
they do without the action of some such adjuvant; and 
that the source of this adjuvant is the adrenal glands 
seems most logical. Whether its effect is exerted 
through the blood stream, in the form of adrenin, as we 
know it, or is brought about through some as yet not 
fully-understood action of the gland upon the nervous 
system, cannot be said with any degree of certainty; 
yet, whatever be the means of transmission, the pre- 
ponderance of circumstantial evidence points to the 
adrenal medulla as the source of the impulse which 
causes the persistence of long-lived urticaria-like le- 
sions. In other words, hyperadrenia most probably is 
the cause of the persistence of angioneurotic edematous 
lesions. 
What then is the cause of the lesions themselves? 
As has been pointed out, we know that ordinary urti- 
caria is preceded by the introduction into the system 
and the blood stream of foreign protein of whatever 
kind, and that angioneurotic edema usually is preceded 
by fright or other nervous shock, by sudden imposition 
of responsibility or other worry, or by exertion to the 
point of fatigue. In the first case probably only the 
foreign protein is a factor. Yet, since urticarias do 
not develop except where elimination is suddenly de- 
creased, the normal alkali reserve of the body lowered, 
and acidosis of degree exists, the addition of a foreign 
protein represents an increased wear and tear upon all 
parts of the system, and thus places added demands 
upon the detoxicating apparatus of which the thyroid 
gland is a prominent factor. To terminal vessel walls 
already irritated by increased blood-borne wastes comes 
added irritation in the form of a new foreign protein. 
To them likewise come added vasodilating impulses 
from increased thyroid functioning. Here and there 
in terminal vessel walls fatigue of vasodilators super- 
venes, often precipitated by external irritation, such as 
