148 



THEORY OF INJURY AND RECOVERY 



In order to calculate the rate of recovery we find by trial the most 

 satisfactory values of the velocity constants. The values thus found 

 are given in Table I. 



TABLE I. 



Velocity Constants. 



As an example of the method of calculation we may take the case 

 of tissue exposed for 15 minutes to a solution of 0.52 m NaCl at 17°C. 

 The net^ resistance in sea water at the start was 960 ohms; in the 

 course of 15 minutes in the solution of NaCl it fell to 775 ohms, which 

 is 80.69 per cent of the original resistance.^ The fall of resistance is 

 a little more rapid than in the "standard curve" obtained in a previous 

 investigation.* If we assume that this is due to the difference in 

 temperature (these measurements were made at 17°C. while those on 

 which the standard curve is based were obtained at 15°C.) we may 

 introduce a correction by multiplying the abscissa by the factor^ 1.06, 

 which makes it 15.9 minutes, and causes it to agree with the standard 

 curve. All the abscissas are multiplied by the same factor.^'' The 



^ The net resistance is that of the tissue itself, obtained by subtracting the 

 resistance of the apparatus from the total resistance. 



"^ For convenience all results are expressed as per cent of the original resistance. 



8 Osterhout, W. J. V., /. Biol. Chem., 1917, xxxi, 585. 



^ This agrees closely with the temperature coefficient as determined in a pre- 

 vious investigation. C/. Osterhout, W. J. V., Biochem. Z., 1914, Ixvii, 272. 



^^ This procedure may displace the points on the curve so that where several 

 curves are averaged it may be necessary to employ interpolation in order to 

 average points on the same ordinate. In man}' cases curves were obtained by 

 averaging the ordinates of death curves and recovery curves before multiplying 

 by the factor. 



