i:)S 



occasional t'rccziiin' of several vacuoles al a lime, ice-seod- 

 iiiii' tliroiiuli llie ineiiil)i"aiies of llie iix'iii^- cells beiuii' often 

 hindered. 



The resulls of .Jensen and Fischer (1910), on muscle, are 

 quite different from the results obtained by the authors that 

 we just mentioned, on plant matcM'ial. The curves of dead 

 muscles dropi)ed more slowly after the horizontal plateau 

 than those of living muscle (Fig. 21). The authors attrib- 

 ute this to a firnirr hiufl'nic] of water in dead material. 



-11.2 



-22.4 



-33. 6 







8 



»2 



/6 MIN. 



Fig. 21. Comparative freezing curves of living and dead muscle (From 



Jensen and Fischer, 1910: ( ), fresh tissue; ( ), tissue killed by 



freezing; (-■-■—), tissue killed hy heating at 100°; (• • • •), tissue killed 

 b_v lieating at 115°. 



The freezing curve obtained by Cameron and Brownlee 

 (1913) on an entire frog exposed to -10° with a ther- 

 mometer in its stomach, seems to agree with the results 

 generally reported rather than with those of Jensen and 

 Fischer. The drop of the curve after the horizontal 

 Ijlateau is slower and does not present the relatively sharp 

 turn exhibited by the hyperbolic curve of a saline solution 

 frozen at the same time (Fig. 22). 



E u t e c t i c Point. Mez (1905) assumed that plant 

 tissues should present a eutectic point just as true solutions 

 do. He claimed, furthermore, that this point was always 

 above -6°. 



