Reprinted from the American Journal of Physiology 

 Vol. XXXII -June 2, 1913 -No. II 



STUDIES ON THE PHYSICAL PROPERTIES OF 

 PROTOPLASM 



I. THE PHYSICAL PROPERTIES OF THE PROTOPLASM OF CERTAIN 

 ANIMAL AND PLANT CELLS 



BY G. L. KITE 



[From the Hull Laboratories of Biochemistry and Pharmacology, University of Chicago] 



INTRODUCTION 



\ LTHOUGH the living substance of animal and plant cells 

 -^A- was correctly interpreted by Dujardin and von Mohl in 

 the second quarter of the nineteenth century, almost nothing is 

 definitely known of the physical state of protoplasm. Properties 

 described by such adjectives as glutinous, slimy and hyaline were 

 recognized by the early micro^copists, who were forced to study liv- 

 ing cells and tissues. 



During the last fifty years an extensive literature has grown up on 

 the subject of the structure of protoplasm. For the purposes of 

 this paper, these investigations may be divided into two groups. The 

 first group comprises those studies on the structure of protoplasm, 

 made with the aid of fixatives. A large part of our knowledge of 

 the morphology of the cells and tissues of animals and plants is the 

 direct result of the development of fixing methods. 



The errors involved in the attempts to determine the true molar 

 structure of protoplasm by the use of fixing reagents have been pointed 

 out particularly by Flemming, 1 Berthold, 2 Schwarz, 3 Fischer, 4 and 

 Hardy. 5 In this connection, it will suffice to state that Hardy's con- 

 clusion that fixing reagents always cause structural changes in pro- 



1 FLEMMING: Zellsubstanz, Kern und Zelltheilung, 1882, Leipzig. 



2 BERTHOLD: Studien iiber Protoplasmamechanik, 1886, Leipzig. 



3 SCHWARZ: Cohn's Beitrage zur Biologic der Pflanzen, 1887, v, p. i. 



4 FISCHER: Archiv fur Entwicklungsmechanik, 1901, xiii, p. i. 



5 HARDY: Journal of physiology, 1899, xxiv, p. 158. 



