24 THE GENERAL CHARACTERS OF THE PROTEINS 



TABLE. 



COAGULATION TEMPERATURES OF SOME OF THE PRINCIPAL PROTEINS. 



Observer. 



SECTION VI L OPTICAL ROTATION OF PROTEIN SOLUTIONS. 



Solutions of proteins are optically active. The rotations, like 

 those of the amino-acids, vary according to the amount of acid 

 present in solution. The number of reliable determinations of the 

 optical rotation of protein solutions is small. Of special interest are 

 those of the vegetable proteins, in which the rotation was measured 

 under as nearly as possible identical conditions. Some of the chief 

 determinations are given in the following table : 



Protein. Rotation. 



Animal proteins : 



Egg-albumin [a]D~3'7 



Haemoglobin [o] c + io - 4\ 



Globin [] c -54'2/ 



Nucleo-proteins Dextrorotatory 



Crystallin (a-variety) [a] D - 46-9 



(0-variety) [o] D - 43-3 



Plant proteins : [a] D 



Edestin (Hemp-seed) -4i'3 



Globulin (Flax-seed) - 43-53 



(Squash-seed) ~3 8 '73 



Excelsin (Brazil-nut) -42-94 



Amandin (Almond) -56-44 



Corylin (Filbert) -43*09 



Globulin (English-walnut) -45-21 



,, (Black-walnut) -44-43 



Phaseolin (Kidney-bean) -41-46 



Legumin (Horse-bean) - 44*09 



Zein (Maize) -28-20 



Gliadin (Wheat) - 92-28 



SECTION VIII. MOLECULAR WEIGHT DETERMINATIONS BY 

 CRYOSCOPIC METHODS. 



(A) Depression of Freezing Point. 



Several data are to be found in the literature referring to the 

 depression of the freezing point of water caused by the solution of 



Hopkins and Willcock. 

 Gamgee and Croft Hill. 

 Gamgee and Jones. 



Osborne. 



