6 9 
ON THE DOSAGE OF THE MAMMALIAN HEART 
BY CHLOROFORM 
By C. S. SHERRINGTON, F.R.S., and S. C. M. SOWTON 
TO measure that dosage of chloroform under which the mammalian heart can 
and cannot continue to work efficiently was a problem given us by the Special 
Chloroform Committee of the British Medical Association.* Our preliminary 
Report was presented to the Committee on February 26 of this year. The present 
Report must be considered to deal still with the first stage of the enquiry. 
M ETHOD 
The method we have followed for perfusion of the heart has been that intro- 
duced by Langendorff' (1895). Our observations have dealt almost exclusively with 
the heart of the cat. We have on occasions used also the heart of the dog. In 
either case the heart was removed from the animal freshly killed. 
Into the aorta, close above its origin, a cannula was tied with its delivery end 
close above the sinuses of Valsalva, as practised by Newell Martin and Applegarth 1 
(1890), and Langendorff 1 (1895). The other end of the cannula was connected 
with a tube leading from a reservoir containing a modified Ringer's solution (Fig. 1). 
This solution was kept warm in a water bath at 3 8° C. It was displaced from the flask 
containing it by introducing oxygen through it into the flask under a pressure 
120 mm. Hg. above atmospheric. It had in the heart cannula a pressure of about 
1 10 mm. Hg. The warm salt solution, after passing through the coronary system, 
collected in the right auricle and there dribbled over, keeping the whole heart moist 
and warm. The heart was held firmly by two clamps, one fixing the root of the 
lung, and thus indirectly the base of the heart, the other fixing the apex of the heart 
by the lower end of the left ventricle itself. A thermometer was let into the side of 
the cannula above the aorta. 
The tube leading to the cannula was Y-shaped, and while one limb of the 
tube led from the reservoir of modified Ringer's solution, the other led from a 
similar though smaller reservoir, in which the modified Ringer's solution contained 
an accurately-measured quantity of chloroform. Both reservoirs were in the same 
water bath, and the fluid in each was similarly supplied with oxygen and under the 
* The Committee consists of Dr. Barr, Dr. Dudley Buxton, Prof. Dunstan, Mr. A. Vernon Harcourt, Sir Victor 
Horsley, Dr. McCardie, Prof. Sherrington, and Dr. Waller (Chairman). 
