VISCOSITY VALUES OF PROTOPLASM AS DETERMINED 



BY MICRODISSECTION 



William Seifriz 



Tl 



Method 



method 



ment employed in this method is a modification of the Barber 

 pipette holder (i). It consists essentially of two needle holders, 

 each capable of three movements. The holders are fastened to 

 the microscope stage, and the two needles held in them project 

 into a glass moist chamber in which the material to be worked 

 upon is suspended in a hanging drop of water on the under side of 

 a cover slip which forms the roof of the chamber. The needles 

 are of glass and possess exceedingly fine but rigid tips. The 

 technique of the microdissection method is fully described by 

 Chambers (7), to whose article the reader is referred. 



The harmful consequences which are likely to result from the 

 practice of holding material in a thin water film, and the importance 

 of this to microdissectionists, make it advisable to direct attention 



1 Botanical Contribution from the Johns Hopkins University, no. 66. 

 Botanical Gazette, vol. 70] [360 













Introduction 



The first descriptions of protoplasm, written nearly a century 

 ago, characterize it as "a living jelly." While protoplasm is 

 often of high viscosity, any restricted statement is likely to be 

 misleading, for the viscosity of protoplasm may vary from a con- 

 sistency slightly more than that of water to that of a firm jelly. 

 From descriptions to be found in current literature it is rather j 



difficult to know of just w r hat degree of viscosity the living sub- 

 stance might be. The difficulty lies in the fact that there has 

 been no careful systematic attempt to ascertain the exact degree 

 of consistency of protoplasm from numerous types of cells and 

 under many different physiological conditions. The following 

 paper represents such an attempt. 







