12 



EXERCISE II 



the small lower glass reservoir (b, text-fig. 6, i), keeping the clamp on the rubber 

 tube closed. Fill this reservoir with ice-cold water, and by opening the clamp 

 allow this to stream through the thin glass tube in the auricle. See that 

 heart-beat is being recorded, the temperature of the coronary supply being 

 about 35° C. Note the result on the rate of beat. By opening the side-way 



Text-pig. 9. Excised rabbit heart, coronary perfusion, a, cooling of perfusion fluid 

 (D. B. Pauw and F. A. D. Petersen) ; b, warming of perfusion fluid (C. C. H. Chavasse 

 and E. G. T. Liddell). 



clamp as well as the reservoir delivery clamp, empty the reservoir of remain- 

 ing cold water ; then fill it with water at 40° C. Open the reservoir delivery 

 clamp and allow this to flow through the tube in the auricle. Note the 

 change in the rate of beat. 



ANNOTATION 



Ohs. 5. The basal fact is demonstrated 

 that the bloodless mammalian heart, excised 

 after it has ceased to beat in the fresh carcase, 

 can be revived to activity and maintained 

 beating by perfusing the coronary blood- 

 vessels with oxygenated normal saline solu- 

 tion. 



The procedure has its foundation in the 

 experiments of H. Newell Martin, 1881 

 [Studies from Biol. Lab., Johns HopMns 



University, especially the paper by Martin 

 and C. Applegarth, Johns Hopkins Biol. 

 Studies, vol. iv, 1890), and the further 

 developments by Langendorff, Arch. f. d. 

 gesammte Physiol. Ixi, 1895 ; Townsend 

 Porter, and F. S. Locke, Gentralbl. f. 

 Physiol No. 26, 1901; No. 17, 1902; 

 Internat. Congress of Physiologists, Turin, 

 1901. The pressure-head of the fluid as 

 supplied in the experiment is below that 



