NHW YW^^K 



B-O'TANsCAL 



A THEORY OF INJURY AND RECOVERY. 

 II. Experiments with Mixtures. 



By W. J. v. OSTERHOUT. 



(From the Laboratory of Plant Physiology, Harvard University, Cambridge.) 



(Received for publication, January 15, 1921.) 



The electrical conductivity of Laminaria changes when the plant is 

 transferred from sea water to 0.52 m NaCl, or to 0.278 m CaClo, and 

 is subsequently replaced in sea water. It has been found that these 

 changes can be predicted with considerable accuracy by means of 

 certain equations. According to the theory of the writer/ the same 

 equations should enable us to predict the changes produced by trans- 

 ferring tissue from sea water to mixtures of NaCl and CaCl2 and then 

 replacing the plant in sea water. 



In order to test this theory experiments were made with a variety 

 of mixtures. The solutions employed are given in Table I. The 

 electrical resistance of the tissue in these solutions is shown in Fig. 1 . 



The experimental data are in good agreement with the values calcu- 

 lated by means of the formula : 



-KaT -KmT\ -KmT 



Resistance = 2,700 ( —-^^ ) ( e - e ) + 90 e +10 



\Km -Ka)\ 



This is evident from Fig. 1, which shows the curves calculated by 

 means of this formula and also the observed values.^ 



^ Osterhout, W. J. V. /. Gen. Physiol., 1920-21, iii, 145. For corrections 

 see the slips inserted in this and in the preceding number of the Journal. 



^ The points shown in Fig. 1 (except those for the solutions containing 1.41 and 



2.44 per cent CaC^ are taken from Fig. 1 of a previous paper (cited below), 



but the curves here given are not identical with those shown in that figure since 



the curves of the present paper represent the calculated values (using the velocity 



,, constants given in Table II) , while those in Fig. 1 of the former paper are merely 



^^ smoothed curves drawn through the observed points. 



o^ . . . 



r— The results described in the former paper as obtained with solutions contammg 



^ 415 



