228 PROTOPLASM 



determined under several shearing stresses. It has been sug- 

 gested that the type of plastic flow of most interest to the biolo- 

 gist may give an apparent fluidity (pa, which will be a function 

 of the shearing stress, as follows : 



<pa = <po -{• oF 



where (pa is the apparent viscosity at zero stress, and a is a 

 constant. 



The viscosity and in particular the anomalous behavior of 

 protoplasm are part of the bigger problem of the structural 

 organization of protoplasm. 



