of Edinburgh, Session 1884 - 85 . 
327 
beat did not merge into that of the auricle, but was perfectly in- 
dependent of it, and the cava continued to beat for at least two 
minutes after the auricular beat had ceased. Whilst the examina- 
tion and stimulation of the right auricle and superior cava were going 
on, the heart had been withdrawn from the blood, and the distension 
had not been kept up. 
At 1.30, on examining the left auricle, it also was found to have 
stopped contracting. It was stimulated with the point of a needle, 
but there was still no contraction. On removing the connecting 
tube from the pulmonary vein and immersing the heart, and pump- 
ing in blood solution until the left auricle was moderately distended, 
there were several distinct contractions which were repeated on 
touching the wall with the point of a needle. Similar contractions 
were obtained at 1.23, 1.24, and 1.26, on applying the point of a 
needle. 
1.23, on stimulating the left auricle with the needle, slight 
fibrillar contractions were observed. On distending the cavity the 
contraction was more distinctly marked. 
1.40, after distension, on stimulating with needle, several very 
strong wavy contractions were observed. 
1.52, dead; not even a fibrillar twitching. 
An attempt was made to induce contraction in the right auricle 
by distending, after the left auricle had been distended and had 
contracted, but without any effect ; not even a fibrillar contraction 
after 12.55. 
Summary . — The right auricle beat regularly for 35 minutes 
after the animal commenced to bleed to death, and 15 minutes 
after the heart was placed in blood. Irregular contractions con- 
tinued for not more than a minute after this. Contraction of 
the superior vena cava continued for two minutes later. The left 
auricle beat regularly for about 55 minutes from commencement 
of the bleeding, and 35 minutes after the heart was placed in 
blood. More or less regular contractions could be induced for at 
least 25 minutes longer. 
It will be seen, on comparison of the two cases, that contractions 
ceased much sooner in the heart specially prepared. It should be 
noted in this connection that there were two points of difference. 
(1) In the first case, tension was maintained in the cavities of the 
