771 



All our equilibria have been maintained for some time, 5 — 10 

 minutes at the least, and we have watched for some latent automatic- 

 pulsation that might exhibit itself, when a single contraction was 

 elicited by a single gentle push. 



Our interest was now excited to see whether by the addition of 

 fluorescein the equilibria would be shifted, and whether this would 

 occur in the same sense as was the case with the summer-equilibria, 

 when compared with the winter-equilibria. The results confirmed 

 our supposition. 



I found e.g. for the equilibria : 

 50 mgr potassium-chloride -f- ^ ^ë^' uranylnitrate = (per liter); 

 100 mgr potassium-chloride -j- 15 mgr uranylnitrate = (per liter), ^) 

 that an extra addition of 100 mgrms of fluorescein to the heart, 

 arrested in equilibrium, made it resume its normal beats. 



For the equilibrium : 



50 mgrms potassium-chloride +6 mgr uranylnitrate = (per liter), 

 I demonstrated the same and also that radiation or an extra addition 

 of 250 mgr of potassium chloride again caused a standstill without 

 injuring the heart in the least, as was made out by a prolonged 

 experiment. 



The same experiment was performed for a potassium-thorium- 

 equilibrium : 



25 mgr potassium-chloride -j- 5 mgr thorium-nitrate = (per liter). 

 By the addition of 100 mgrms of fluorescein the pulsations recurred 

 and this time by an increment of 50 mgr of potassium-chloride a 

 fresh standstill was brought about. 



It will be understood that finally in all these experiments a 

 perfusion of potassium-free fluid was administered, after which the 

 normal Ringer's mixture made the heart recover its normal condition. 



It is evident, then, that fluorescein promotes the sensibility to the 

 radio-active elements, in the same way as the summer does, viz. 

 the action of the -heavy metals more than that of the light ones. It 

 follows that an increment of light metal is wanted to restore the 

 equilibrium. Mesothorium-radiation can also be taken instead of 

 potassium. We might also put it in this way: that both the summer 

 and the fluorescein depress the curve of the potassium-uranium 

 equilibria (also that of the rubidium-uranium equilibria, besides that 

 of the potassium-thorium equilibria). Calcium, on the other hand, 

 yields a higher curve. What must be done to restore the equilibrium 

 may be gathered from the curve itself. 



') Different types of animals. 



