THE COLLOIDAL STATE. 57 



formation of structures in gels we are dealing with true 

 coagulationSo The experiments may easily be varied and 

 similar results be obtained by using other fixing agents and 

 non- electrolytes. It may be pointed out, in passing, that 

 histology could easily employ to advantage this property 

 of the non-electrolytes, especially that of urea, for obtain- 

 ing a finer gradation in its methods of hardening and 

 fixing tissues, as well as for causing changes brought 

 about through these methods to disappear more or less 

 perfectly. 



All physico-chemical investigations that have been de- 

 scribed here indicate, therefore, that the condition oj 

 swelling in colloids is not to be looked upon as a diphasic 

 one, and that the reasons which have thus far been 

 advanced in favor of such an assumption do not bear 

 careful criticism. We can therefore find in the prop- 

 erties of the jellies no arguments for believing that proto- 

 plasm is a strictly diphasic system having a finely 

 honeycomb structure. No doubt the substance of the 

 cell may, in those instances in which we have to deal 

 with inclusions of such substances as colloidal carbo- 

 hydrates or fats, represent a heterogeneous complexity 

 with phases the relations of which to each other are 

 subject to the laws of chemical equilibrium. In general, 

 however, such inclusions take part only indirectly in the 

 actual life processes of the cell. At present no cogent 

 reason exists for not believing that the mass which is 

 looked upon as the bearer of life processes may not well 

 be monophasic in structure. 



According to a view expressed years ago and based on 

 studies of the way in which water is held in gels, the 

 colloidal particles of the latter are believed to contain 



