2 5 8 



WALTER E. CARREY. 



atmospheres for a depression of one degree centigrade ( i C.). 

 The depression of the freezing point is designated J. Owing to 

 the super-cooling which takes place in solutions as strong as those 

 with which we are dealing, inconstant results are obtained unless 

 freezing is induced by innoculation with a tiny crystal of ice as 

 soon as supercooling of about three tenths of a degree has taken 

 place. A few earlier experiments in which this technique was 

 neglected have not been recorded here. Invertebrate blood clots 

 slowly and the first clot is easily broken up so that the freezing 

 point of fluid as a whole may be determined. Teleost blood was 

 whipped before freezing but no attempt was made to remove the 

 corpuscles in as much as it has been found that they exert no 

 appreciable effect upon the freezing point (Hamburger 11 , Hedin 12 ). 



OSMOTIC PRESSURE OF SEA WATER. 



The animals worked with at Woods Hole were obtained from 

 so many different localities that it seemed advisable to determine 

 the freezing point of the water from the same sources. The re- 

 sults of these determinations are given in Table I. 



TABLE I. 



The slight variations noted in the concentration of the different 

 samples of sea water are not due to errors in observation for 

 each sample of sea water was tested repeatedly and the results 

 were checked by the use of three thermometers. The variations 

 may be explained by the more or less land-locked condition of 

 the bodies of water, the concentration being continually, though 

 slightly, altered by the tides and by the continued advent of fresh 

 water. After one extremely heavy rain the water of the labora- 

 tory tap showed considerable dilution J being -- 1.78. "Eel 

 Pond" water also was diluted till the freezing point was only 

 - 1.70. 



