W. J. V. OSTERHOUT 149 



effect of this is to make the process appear to proceed at 15 instead 

 of at 17°C. If the difference between the two curves is due wholly 

 to difference in temperature this introduces no error, and if the differ- 

 ence is due in part to other factors, the error, if any, is less than the 

 usual experimental error. 



The advantages of this procedure are that we can employ for our 

 calculations the constants already obtained for the standard curve 

 and also compare the theoretical curves which start from the same 

 points. This procedure has therefore been followed throughout and 

 the corrected results {i.e. the figures multiplied by a suitable factor) 

 are employed in the following description. 



When the tissue was replaced in sea water the resistance began to 

 rise. At the end of 10 minutes it had risen from 80.69 to 92.57 

 per cent.i^ Since, however, the abscissae of the death curve have 

 been multiplied by 1.06 the same thing must be done for the 

 recovery curve and in place of 10 minutes we must put 10.6 minutes. 

 Proceeding in this manner we obtain the recovery curve which is 

 labeled 15.9 in Fig. 1. 



In order to calculate the course of the recovery curve we must 

 consider the reactions which determine the amount of electrical resist- 

 ance. When the tissue is placed in the solution of NaCl the reac- 

 tions which occur are: (1) A -^ M —> B; {2) R -> S -^ T; and 

 (3) N -^ —^ P. Let us first consider the reactions A -^ M —^ B. 

 The value of A in sea water is taken as 2,700 and that of M as 90. 

 As explained in a former paper^ the value of A will diminish during 

 exposure to NaCl according to the formula 



A e-^^^ (2) 



Since K^ = 0.018 (see Table I) the value of A after 15.9 minutes 

 in sea water is 



2,700 g- (0-018) 15.9 =2,027.96 



The value of M at the end of 15.9 minutes is the observed resistance 

 80.69 less 10 (since the base line of the curve is not but 10). 



^^ In earlier experiments it was found that complete recovery was possible 

 after the resistance had fallen to about 80 per cent. This was not the case in the 

 present series; the difference may be due to differences in material or in technique. 

 C/. Osterhout, W. J. V., BoL Gaz., 1915, lix, 242. 



