PROTEINS. 



distinctive properties as it is purified from phosphates ; and, on 

 the other hand, the non-coagulable modification should be 

 capable of being converted into the other by associating it with 

 phosphates ; neither alternative has as yet been found possible, 

 and, as two proteins having distinct properties can be separated 

 from milk, Duclaux's view is hardly tenable. 



Hammarsten describes two proteins ; one, casein, corre- 

 sponding to Duclaux's coagulable casein ; the other, lact- 

 albumin, corresponding to Duclaux's non-coagulable casein. 

 He shows that lactalbumin has the properties of a true albumin, 

 approaching very closely to serum-albumin, but differing from 

 it in certain physical constants, which entitles it to rank as 

 a distinct body. Crowther and Raistrick confirm this. Sebelein 

 has shown that there exist in milk traces of a globulin, in addi- 

 tion to the casein and albumin of Hammarsten. 



Halliburton describes the proteins of milk as caseinogen 

 and lacto-albumin ; there is no essential difference between the 

 casein of Hammarsten and the caseinogen of Halliburton, except 

 a difference of name. He reserves the name casein for the curd 

 produced by the action of rennet. 



Osborne and Wakeman have separated an alcohol-soluble 

 protein from the casein precipitated by acids. 



Hewlett has confirmed Sebelein's statement as to the existence 

 of globulin in milk, though he has shown that Sebelein's globulin 

 was probably contaminated with small amounts of casein. 



Musso and Menozzi have claimed the presence in milk of a 

 body midway between casein and albumin ; this is probably the 

 globulin of Sebelein in an impure state, as their description 

 is in fair accordance with a statement of the properties of the 

 latter. Crowther and Raistrick state that the globulin is identical 

 with serum globulin. 



Radenhausen and Danilewsky have described many proteins 

 in milk. Hammarsten and later Chittenden and Painter have 

 shown that their view that casein is a mixture of two compounds 

 is untenable, while the various lacto -protein bodies have been 

 shown to be the result of their method of separating casein and 

 albumin. 



Wroblewski describes a protein opalisin which is salted out 

 after precipitating the casein by acetic acid, abundant in human 

 milk, but only occurring in traces in cow's milk. 



Wynter Blyth has described a body called galactin in milk ; 

 this is essentally lacto-protein, perhaps contaminated with some 

 organic salts, and has no real existence in milk, being portions 

 of the casein and albumin which had escaped separation, together 

 with products of their decomposition during the process used for 

 their removal. 



