i:)9 



-12 



Fig. 22. Comparative freezing curves of an entire frog (x x x) and of 

 a saline solution (o o o). (After Cameron and Brownlee, 1913.) 



On Mez' suggestion, Voigtlander (1909) established a 

 large number of freezing curves of various plant tissues. 

 He observed that in most of them the cooling velocity 

 showed a decrease at two points along the curves (Fig. 7, 

 Curve 5, Points F and E), and he considered these retarda- 

 tions in the cooling rates as representing, respectively, the 

 freezing and the eutectic points. 



According to Fischer (1911), it is quite daring to speak 

 of the eutectic point of the cell constituents which are mix- 

 tures of colloidal substances, some of wiiich perhaps never 

 crystallize. Jensen and Fischer (1910), who made a com- 

 parative study of the freezing curves of muscles and of 

 saline could observe a faint trace of eutectic in the latter 

 but their curves show no evidence of any eutectic in the 

 muscle. 



Maximov (1914) criticized Mez and Voigtlander 's results 

 on the ground that, in such a dilute solution as the cell sap, 

 the retardation in the drop of the curve caused by a 



