W,. J. V. OSTERHOUT 



427 



consequent agreement between observed and calculated results is less 

 significant than would otherwise be the case. But, as a matter of 

 fact, the constants are so related to each other and to the salt com- 

 pound, Na-iXCa that the whole set of curves fits into a consistent 

 scheme, so that when the constants are determined for any two mix- 

 tures the theoretical curves for all the other mixtures are thereby 

 fixed. Under these circumstances the close agreement in the si^ dif- 

 ferent mixtures (ranging from 1.41 to 62.0 per cent CaCh) seems to be 

 significant. 



There seems to be no doubt that the behavior of the tissue is such as 

 to indicate an underlying mechanism which is the same in all cases.^^ 

 We have assumed that this mechanism consists in the production and 

 decomposition of a substance, M, the amount of which, in the mix- 



FiG. 7. Curves showing the electrical resistance (curve which ascends and de- 

 scends) oi Laniinana agardhii in a mixture containing 95.24 mols of NaCl to 4.76 

 mols of CaCl2, and recovery in sea water (descending curves) . The figure attached 

 to each recovery curve denotes the time of exposure (in minutes) to the toxic solution. 



In the recovery curves the experimental results are shown by broken lines, 

 the calculated results by 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. 



^^ This is shown, for example, by the fact that the rapidity of permanent 

 injury (as observed after replacement in sea water) corresponds throughout with 

 the rate of death, and that the rate of change of M corresponds throughout with 

 the rate of change of 0, S, and A. In other words if we change the solution in 

 such a way as to increase (or decrease) the rate of one of the reactions on which the 

 resistance depends we simultaneously increase (or decrease) the rates of all the 

 others in a definite and predictable manner. 



