i9.2o] SEI FRIZ— PROTOPLASM 367 



only lead to misinterpretations regarding the true viscosity of 

 protoplasm. 



It is very probable that much of the unfavorable criticism of 

 Kite's work is due, not to faulty observations, but to his lax use 



term gel. For exam 



erm 



and not with a gel as Kite (according to Garrey) maintains; but 

 who is to decide that the liquid which Garrey sees is not the same 

 kind of substance which Kite saw if gel means one thing to Kite 

 and another thing to Garrey ? Sol and gel should be used with 

 great caution in describing the physical state of matter when one 

 is dealing with an emulsion. It is better to give some idea of the 

 viscosity of the substance and let that suggest a possible sol or 

 gel state. It is well to emphasize the fact that protoplasm is not 

 a simple two-phase colloidal system, as one is led to believe from 

 reading much of the literature. On the contrary, it is a multiphase \ 



system, emulsion within emulsion. ^ 



General viscosity values of protoplasm 



asm 



organism 



organism at the same time. Further- 



more, 1 

 matrix 



cosity of the protoplasm as a whole, and from each other. The 

 examination of an inactive Myxomycete Plasmodium will frequently 

 reveal a ground substance of very low viscosity, while the mass of 

 protoplasm as a whole is of high consistency. This relation 

 between the viscosity of the constituents of an emulsion and that 

 of the emulsion as a whole is very evident in certain artificial 

 emulsions. For example, in a dispersion of gelatine the viscosity 

 of the medium (water) at 20 C. is 0.012, while the viscosity of 



times 



great (o . o x 7) . 6 The most 



of an emulsion as compared with the low viscosity of its dispersion 



6 This reading (from Taylor 27) seems surprisingly low, since a 2 per cent con- 

 centration of gelatine will ordinarily set into a jelly at a room temperature of 18 C. 



