OF THE CALABAR BEAN. 747 



Experiment L. — {Temperature of Laboratory, 60° F.) 



The exposed heart of a frog, weighing 469 grains, was found to contract, on an average, 

 sixty-seven times in the minute. One grain of extract, in five minims of water, was^then injected 

 into each thigh, and a third grain was injected into the stomach by means of a narrow caout- 

 chouc tube (total three grains). 



2 minutes afterwards, cardiac contractions = 60 per min. 



4 „ „ = 54 „ 



6 „ = 34 



8 „ = 30 



1 r. _ 91 f Very feeble. Heart not quite so pale, 



" \ now, in systole. 

 12 „ „ = 13 



.., .... (Frog jumped about when set free, but 



- r. " { soon fell on its back, and remained 



16 " " = 8 „ | them 



18 „ „ = „ | Colour of frog has changed from 



20 „ „ = „ J yellowish brown to dark bronze. 



22 „ „ =0 „ of the ventricles, 2 of the auricles. 



24 „ „ - 



28 „ „ =0 „ 



30 „ „ =0 



After this, an occasional auricular contraction occurred, but no spontaneous movement was 

 seen of the ventricles. The heart rested in diastole, and was of a dark colour with a bluish 

 tinge. For twenty minutes after this, a slight stimulus excited a few rhythmical contractions, 

 followed, in a few seconds, by rest in diastole, but capable of being reproduced in the same way. 

 One hour and ten minutes after the administration, no reflex movement could be excited ; but 

 the sciatic nerves continued active for longer than thirty hours — the rapid stoppage of the circu- 

 lation having prevented that prolonged contact with the poison that is necessary for the 

 paralysis of the endorgans. The striped muscles remained contractile until more than forty- 

 eight hours, and contractility was also retained by the cardiac muscle during this period. 



A possible source of fallacy is introduced into these experiments by the opera- 

 tions that they require. It seemed, therefore, of some importance to test the 

 effects on the frog's heart of mere exposure to the air. For this purpose, a portion 

 of the sternum was removed from an active frog, in exactly the same manner as 

 in the last four experiments, with the following result : — 



5 minutes afterwards, cardiac contractions = 62. 



= 61. 

 = 62. 

 = 59. 

 = 60. 

 = 59. 

 „ = 55. 



= 57. 

 = 60. 

 = 56. 

 = 58. 

 = 59. 

 = 59. 



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VOL. XXIV. PART 



III. 







