RECENT INVESTIGATIONS ON THE PROTOPLASM 



OF PLANT CELLS AND ITS COLLOIDAL 



PROPERTIES 



FREDERICK CZAPEK 



Pflanzenphysiologisches Institut der K. K. Deutschen Universitdt, 



Prague, Austria 



I have the honor of publicly congratulating the Representa- 

 tives of the Missouri Botanical Garden upon the Twenty-fifth 

 Anniversary of Henry Shaw's magnificent foundation, — the 

 unique memorial of a magnanimous citizen of this great 

 metropolis. 



I shall endeavor to show to the members of this splendid 

 assembly how plant physiologists at present attempt to reach 

 a satisfactory understanding of the wonderful mechanism 

 which in never-ceasing variation is unfolded to us in myriads 

 of phenomena characteristic of nutrition, reproduction, adap- 

 tation, growth, and stimulation, in the lower as well as in the 

 higher plant organisms. 



Wherever science is following these various processes to 

 their mysteriously hidden roots, the physiologist has to face 

 the complex problems associated with the living content, the 

 so-called protoplasm of the plant cell. Without this singular 

 matter plant cells are mere dead bodies able neither to grow, 

 to take up food, nor to assimilate their nutriment. 



It was not until 1841 that Hugo von Mohl, the well-known 

 botanist of Tubingen, discovered the important fact that all 

 phenomena in cell life are strictly confined to the thin layer 

 of slimy material which clothes the inside of each growing and 

 living plant cell. He stated that this protoplasmic slime was 

 stained deeply yellow by means of iodine, and he expressed 

 the opinion that protein substances in particular were the con- 

 stituents of this living material, from which all other parts 

 and organs of the cell were believed to take their origin. 



We shall not be surprised to learn that biologists felt in- 

 clined to suppose that the protoplasm might contain some 



Ann. Mo. Bot. Gard., Vol. 2, 1915 



(241) 



