426 THEORY OF INJURY AND RECOVERY. II 



owing to the fact that 6" affects only the speed of recovery fnot the 

 final level attained) and as the speed is variable the most satisfactory 

 procedure is to assume such values of Kj^ and K^ in the equation^^ 



■KrT -KsT\ -KsT 



S = R[ —^^^^-^ ) ( e - e ) + 5o e 



\^A'5 - Kr) \ 



as cause the closest approximation to the observed speed of recovery. 

 The values of 5 thus obtained for each solution are shown in the fig- 

 ure. In general the speed of recovery, as calculated from these 

 values of S, is in satisfactory agreement with the observations. 



By means of the equations given in the previous paper, and of the 

 velocity constants in Table II of this paper, we are able to calculate 

 the recovery curves for any solution after any length of exposure. 



Fig. 6. Curves showing the electrical resistance (descending curve) of Laminaria 

 agardhii in a mixture containing 97.56 mols of NaCl to 2.44 mols of CaClo and re- 

 covery in sea water (ascending curves). The figure attached to each recovery 

 curve denotes the time of exposure (in minutes) to the toxic solution. In the re- 

 covery curves the experimental results are shown by the broken lines, the calculated 

 results by the unbroken lines. The observed points represent the average of six or 

 more experiments. Probable error of the mean less than 10 per cent of the mean. 



Lack of space prevents a tabulation of the observed and calculated 

 values, but it is possible to exhibit graphically the data for three mix- 

 tures and for this purpose one in which recovery consists in a rise of 

 resistance (Fig. 6), one in which it shows a moderate fall (Fig. 7), 

 and one showing a very decided fall (Fig. 8) are presented. In general 

 the agreement between observation and calculation is satisfactory 

 for all the solutions employed in the investigation. 



It might be thought that the number of constants is sufficient to 

 make it possible to fit any sort of experimental curve and that the 



^^ Cf. equation (3) of the preceding paper (Osterhout, W. J. V., /. Gen. Physiol., 

 1920-21, iii. 145) 



