1 889 . J BOTANICAL GAZETTE. 



2;i9 



If we look at the hand-books of botany just before this 

 date of the early forties, we find references to "coagulabh- 

 matters" (Treviranus), and the chemical instability of the 

 substance within cells was suspected of having much to do 

 with its activity, but almost all of the notes, as well as those 

 upon the same subject found here and there in philosophical 

 writings of the latter part of the last century, are based on 

 pure speculation. The scientific recognition of a physical 

 basis of vital activity must be credited to Schleiden and 



Mohl. 



The term protoplasm was at once adopted by Schleiden, 

 and a good substitute for the indefinite and misleading word 

 schleim, which he had employed to designate essentially the 

 same substance, and it became thoroughly established in 

 scientific terminology. In 1850, Prof. Cohn (and Unger in 

 1 '^55 ^showed that the protoplasm of vegetable cells is identi- 

 cal with what had been described, in 1835, in animal struct- 

 ures as sarcode by Dujardin, and this prepared the way for 

 the exhaustive treatise by Max Schultze in 1858. From that 

 date on, work in the contiguous fields of botany and zoology 

 has made no physical or chemical distinction between the 

 living-matter in animals and plants. Investigators in the two 

 fields have been mutually helpful. 



Mohl, in his treatise on the vegetable cell, published in 

 l $5 l i gives the following account of protoplasm : 



" If a tissue composed of voung cells be left some time in 

 alcohol, or treated with nitric or muriatic acid, a very thin, 

 finely granular membrane becomes detached from the inside 

 of the walls of the cells, in the form of a closed vesicle, which 

 becomes more or less contracted, and consequently removes 

 all the contents of the cell which are enclosed in this vesicle 

 Horn the wall of the cell. Reasons hereafter to be discussed 

 have led me to call this inner cell the -primordial utricle 

 {priniordialschfauch). * * * In the center of the young 

 cell, with rare exceptions, lies the so-called nucleus cmulaoi 

 Robert Brown (.♦ Zellen-kern ; ' Cytoblast" of Schleiden). 

 * * * The remainder of the cell is more or less densely 

 filled with an opaque, viscid fluid of a white color, having 

 granules intermingled in it, which fluid I call protoplasm." 



We must now pass without notice numerous contributions 

 to the subject and consider Hofmeister's description of proto- 

 plasm given in his Vegetable Cell, published in 1867. 



"The substance protoplasm, whose peculiar behavior in- 

 itiates all new development, is everywhere an essentially 



