OF VITAL PHENOMENA 75 



Caseinogen (in milk) 

 Gelatine (1 per cent) 

 Hemoglobin (1 per cent) 

 Serum albumin 

 Protalbumoses 

 Duteroalbumoses A 

 Deuteroalbumoses B 

 Dextrin 



Emulsoids enormously increase the viscosity of water. One per 

 cent gelatine increases the viscosity of water 29 per cent. 



Emulsoids reduce the surface tension and are therefore ad- 

 sorbed. They become denatured in the surface film to the extent 

 that they no longer go into solution in some cases (haptogen 

 membranes). In this way they may be precipitated by shaking 

 the solutions. The surface films are submerged and distorted, 

 forming stringy masses, while new surface films are formed. 

 Emulsoids adsorbed by solids cannot be washed out with water 

 because they have become insoluble. Emulsions of oil and water 

 are permanent if colloids are present as the haptogen membranes 

 formed about the oil drops prevent them from fusing. Soap 

 acts in this way. Some colloid from milk glands forms haptogen 

 membranes around the fat droplets, but it is said not to be casein- 

 ogen. The plasma membrane on the surface of protoplasm is 

 supposed to be of this nature although the colloids in its composi- 

 tion have not been ascertained. Presumably, the colloids of the 

 cell: proteids, lecithins, and cholesterin, enter into its composi- 

 tion. 



Emulsoids are not precipitated by small amounts of electrolytes 

 unless they have been denatured. They may be salted out by 

 large amounts of neutral salts in the same way that truly dis- 

 solved substances, such as gases or alcohol, may be salted out 

 of their aqueous solutions. The electric charge of the colloid 

 is not entirely without significance in the salting out process, 

 however, as will be seen in the anionic series. The order of 

 effectiveness of anions in salting out soluble non-electrolytes is 

 (beginning with the least effective): CNS, I <NO s <C1 

 <CH 3 COO <S0 4 <Tartrate <Citrate (Hofmeister, 1891). 

 The order of effectiveness with negative emulsoids is the same, 



