2] 



EFFECT ON STRUCTURE AND FUNCTIONS 



83 



Thus, in this case there is a diminution in the resistance period 

 of approximately 1 minute for every degree of increase in the 

 temperature. 



Similar observations have been made by others. GOGORZA 

 ('91, p. 242) finds that in all animals, at a low temperature, the 

 resistance period is 2 to 3 times as long as at a high temperature. 



In connection with these facts, it is to be noted that osmotic 

 pressure increases with temperature, indeed, is proportional to 

 the absolute temperature. (OsTWALD, '91, p. 114.) But as 

 we are not able to say what relation exists between osmotic 

 pressure and resistance period, we cannot say whether the above 

 table agrees with the physical law. 



Finally, we may discuss the question of the relation between 

 the strength of the solution and the length of the resistance 

 period. Data for this discussion are afforded by the extensive 

 observations of GOGORZA. This author disclaims having found 

 any mathematical relation, but his tables, properly treated, do 

 show such a relation. The resistance periods depend upon so 

 many factors that the times obtained by subjecting one animal 

 to different concentrations of a salt cannot be directly compared 

 with those obtained from another animal. It is the relative 

 resistance periods only that can be thus compared.* GOGORZA'S 

 concentrations were obtained by subjecting marine animals to 

 mixtures of marine and fresh water. No. 1 contained 100% 

 sea water; No. 2, 75%; No. 3, 60%; No. 4, 50%; No. 5, 33%; 

 No. 6, 25%; No. 7, 0%. Averaging the relative lengths of 

 life of 22 species which died in 75%, or weaker percents of 

 sea water, and comparing with the percentage of salts in various 

 concentrations (the density of Mediterranean sea water being 

 taken as 1.037), we get 



* The relative resistance periods are calculated by the method described 

 on p. 82. 



