J 92o] SEIFRIZ—PROTOPLAS.]f 38 



plasm increases in viscosity coincident with a decrease in activity, 

 both the number of particles exhibiting Brownian movement and 

 the amplitude of vibration are lessened. This fact is expressed in 

 the physical law which states that the amplitude of vibration of a 

 particle of a given size is inversely proportional to the viscosity of 

 the dispersion medium (8). This law is further supported by the 

 fact that in highly viscous living protoplasm no Brownian move- 

 ment is to be seen. 



Brownian movement of particles is so characteristic a phe- 

 nomenon of degenerate protoplasm that I was led to look upon it 

 as an "unfailing criterion of degeneration" (23). Such a con- 

 clusion, in view of the presence of Brownian movement in living 

 protoplasm, is not justifiable. It is true, however, that one of the 

 first signs of degeneration in protoplasm, which in the living 

 normal condition shows no Brownian movement, is the instant 

 assumption of a marked oscillating motion of the protoplasmic 

 particles. The surprising thing, however, is that this Brownian 

 movement is actually taking place in an apparently highly viscous 

 mass. Careful dissection will reveal the fact that the degenerate 

 protoplasm has gelated only at the surface, sometimes to an 

 appreciable depth, while the interior of the mass is very dilute. 

 It is in this watery degenerate protoplasm that the suspended 

 particles are in vibration. 12 Death, therefore, has resulted in a 

 liquefaction, probably due to excessive imbibition of the proto- 

 plasm. This fact is not generally realized, primarily because the 

 watery condition is only temporary, since ultimately the whole of 

 the protoplasm becomes a rigid coagulum. Gaidukov (9), for 

 example, in describing the death changes which take place in the 

 living emulsion, says that "with death of the plasma a coagulation 

 results, which in the case of slow death, is a precipitation, and of 

 sudden death (by fixation), a congealing." I wish again to empha- 

 size the fact that this liquefaction of the protoplasm is a conse- 

 quence of death, and not of mere injury. Injury, not resulting in 

 death, invariably produces an increase in viscosity. It is not 

 true, therefore, that Brownian movement of microscopic parti- 

 cles in protoplasm ends with death (2). On the contrary, it is 



13 Diffusion of the dilute protoplasm is prevented by rapid gelation at the surface. 





