NUTRITION OF THE HEART. 



225 



With respect to the first question, the object of all investigators has been to 

 remove the blood out of the ventricle or apex-preparation by means of a normal 

 saline solution, and then when, in consequence of the washing out with the 

 salt solution, the ventricle has ceased to beat, or is beating very weakly, to send 

 in the fluid to be tested, and see whether the heart recovers its contractions. 

 By the experiments of Merunowicz 1 in 1874, it was shown that the apex of the 

 heart, when reduced to standstill by washing out with normal saline solution, 

 could be made to beat again by sending through it a solution of the ashes of 

 blood or serum ; and among the different constituents in such ashes Merunowicz 

 supposed that sodium carbonate was the most important, and that a solution of 

 sodium carbonate and sodium chloride alone was able to resuscitate the 

 motionless apex. Gaule, 2 following on Merunowicz and using Kronecker's 

 perfusion cannula and the whole heart, proved that sodium hydrate was more 

 efficient than sodium carbonate, and that when the heart no longer responded 

 to the alkaline solution it could again be brought to renewed activity by 

 sending through it for a second time the alkaline solution which had already 

 passed through. 



He attributed its efficiency over the simple alkaline salt solution to albu- 

 minous substances taken up from the heart ; he came to the conclusion that 

 amongst such substances peptones were especially efficient when added to the 

 alkaline fluid. This conclusion of Gaule's was tested, and not confirmed, by 

 Martins 3 in Kronecker's laboratory. He found peptones absolutely useless, 

 after the heart had been thoroughly washed out by an alkaline fluid ; and came 

 to the conclusion that the whole value of the alkaline solution was to remove 

 the acid products of metabolism ; and he and Kronecker came to the conclusion 

 that the perfused fluid must contain serum albumin, and, further, that any fluid 

 which maintained the cardiac contractions must contain this substance. 



In a series of papers commencing in 1882, 4 Ringer showed that a 

 solution, containing sodium chloride, potassium chloride, and calcium 

 chloride alone, would act as an efficient circulating fluid for the frog- 

 ventricle, provided the salts in question were present in certain propor- 

 tions. He found (as had been done by Merunowicz) that sodium 

 chloride alone soon brings the heart to a standstill in diastole, but he 

 further showed that the addition of a lime salt causes the beat to be 

 prolonged by delaying the diastole, and eventually produces stillstand 

 in systole. 5 The potassium salt, on the other hand, when added to this 

 mixture, antagonises the effect of the lime salt, and produces a normal 

 beat. The solutions must be prepared with distilled water, since 

 nearly all natural water contains an appreciable quantity of lime in 

 solution. 



The circulating fluid which Ringer eventually adopted is made as 

 follows : — 



A - 6 per cent, solution of sodium chloride is saturated with calcium 

 phosphate, and to each 100 c.e, of the mixture, 3 c.c. of a 1 per cent, 

 solution of potassium chloride is added. 



Howell and Cooke have lately shown that, if the heart is washed out 

 with saline solution and Martins' fluid to exhaustion, and then supplied with 

 Ringer's fluid, not oidy will it beat again, but they have seen such beating 



1 Ber. d. k. sacks. Gesellsch. d, Wissensch., 1875, p. 252. 



*Arch.f. Physiol., Leipzig, 1878, S. 291. :: Ibid., 1882, S. 548. 



Jinirn. Physiol., Cambridge and London, vols. Hi., iv., and vi. 

 ' Ibid., vol. iv. pp. 29, 222. 

 * Ibid., 1893, vol. xiv. p. 198. 



VOL. II. — 15 



