a. L. INMAN 



535 



which time they were placed in the chamber (with a little of the same 

 liquid as that with which they had been treated) and the rate of respi- 

 ration was then measured at intervals of 10 to 20 minutes, until the 

 expiration of 60 minutes. 



The concentrated solutions of sea water were obtained by slow evap- 

 oration of normal sea water both with and without the use of heat. 



30 eOmin. 



Fig. 1. Curves showing the rate of respiration of Laminaria during exposure 

 to sea water of various specific gravities and freezing point depressions. A for 

 Woods Hole sea water is normally — 1.81 and the specific gravity 1.024. The 

 ordinates represent the rate of production of CO2 expressed as per cent of the 

 normal. The normal rate represents a change in pH from 7.78 to 7.36 in from 

 1.5 to 2 minutes. The abscissae represent time in minutes. Average of 3 or more 

 experiments: probable error of the mean less than 10 per cent of the mean. 



No difference was found in the results they produced when of the same 

 concentration. Artificial sea water (van't Hoff's solution, without 

 the carbonates) in high concentration affected respiration in the same 

 manner as ordinary concentrated sea water. The specific gravity 

 of the sea water was measured by means of a Westphal balance and 



