ROYAL IRISH ACADEMY. 
291 
We have studied the enlarged condition of the oval tumour produced 
by M. Groux, after deep inspiration, followed by suspension of further 
respiratory effort. It has appeared to us, under this condition, to reach 
at least three times its ordinary volume: and this circumstance, were 
there no other, furnishes a strong argument in favour of the opinion 
that the tumour in question is the right auricle. In the distended state 
the pulsation becomes feeble, irregular, and fluttering, and apparently 
more rapid. 
18th. By certain respiratory efforts M. Groux can arrest the radical 
pulse in both wrists. 
19th. There is a peculiar condition of the heart’s action induced in 
M. Groux by certain respiratory efforts, which is worthy of notice, though 
not bearing upon the main question upon which we have been appointed 
to report. It is the production of a strong pulsation at the left side, and 
referrible to the body of the heart. To induce this, M. Groux makes use 
of the following succession of actions. He takes a very deep inspiration, 
and then, by a long regulated expiratory effort, expels the air from his 
lungs as far as it appears possible to carry this process. Towards the 
close of this expiratory effort the pulsation of the heart is felt with 
great force, and with a kind of struggling motion, in the third, fourth, 
and fifth intercostal spaces, between the left border of the sternum and 
a line passing vertically through the left nipple. During this time the 
stethoscope, placed on the anterior part of the right side of the chest, 
seemed to indicate a period of apnoea, while a loud muscular murmur, 
apparently referrible to the action of the intercostals, was heard. 
If it be assumed that in this case there is no abnormal condition of 
the heart or great vessels, we may inquire what is the actual nature of 
the pulsating tumour. 
The possible causes of a pulsation in the sternal region may be 
enumerated as follows :— 
I. The pulsation of the base of the heart itself, and principally of 
that of the right ventricle. 
II. The pulsation of the pulmonary artery. 
III. The pulsation of the aorta. 
IY. The action of the right auricle. 
Against the first hypothesis there is to be urged:— 
a. The want of synchronism between this pulsation (that of oval 
tumour) and the impulse in the left infra-mammary region. 
b. The singleness of the pulsation. 
c. The direction of the action of the tumour, which is from above 
downwards. 
The following considerations lead us to reject the second suppo¬ 
sition :— 
1. That this pulsation precedes the stroke of the heart. 
2. That it is single, and from above downwards. 
