ON THE ELECTRICAL CHARGE OF PROTEIN. 1^7 



is not apparent along which it will one day become 

 possible to discover its structure. 



7. On the Electrical Charge of Protein and its 

 Significance.* 



I. 



THE surprising development of the chemistry of the 

 colloids, which in no small part has been incited through 

 its great biological importance, has reacted most benef- 

 icently upon the latter science and many problems in 

 general physiology. I have repeatedly had the honor 

 of bringing before this society reports of that daily 

 increasing territory in which the study of colloidal reac- 

 tions touches upon or coincides with that of the struc- 

 ture and changes in state, and in consequence the func- 

 tions of the cells and fluids of the organism. 



If one attempts to survey the long series of colloidal 

 substances and to study along the lines common to all, 

 it must become apparent to every one how markedly 

 their typical properties vary in degree in spite of a certain 

 identity in behavior in the matter of diffusion, for example; 

 and how the presence or entire absence of certain prop- 

 erties changes the whole character of a colloidal reaction. 

 This holds not only for the fundamental differences 

 between the solid and jelly-like colloids, or gels, and the 

 liquid colloids, or sols, but also for the individual mem- 

 bers of each of these groups. In fact, we see that among 

 the sols the proteins constitute an almost independent 



* From Naturwissenschaftliche Rundschau, 1906, XXI, p. 3. Ad- 

 dress delivered before the Morphologisch-physiologische Gesellschaft in 

 Vienna, December 5, 1905. 



