PROGRESS IN ANATOMY AND PHYSIOLOGY 



by Treviranus, and that these observers had described 

 the phenomenon under the u most unsuitable name of 

 ' rotation of the cell sap.' r Yon Mohl recognized that 

 the streaming substance was 

 something quite different 

 from sap. He asserted that 

 the nucleus of the cell lies 

 within this substance, and 

 not attached to the cell wall 

 as Schleiden had contended. 

 He saw, too, that the chlo- 

 rophyl granules, and all 

 other of the cell contents, 

 are incorporated with the 

 " opaque, viscid fluid," and 

 in 1846 he had become so 

 impressed with the impor- 

 tance of this universal cell 

 substance that he gave it 

 the name of protoplasm. Yet in so doing he had no inten- 

 tion of subordinating the cell wall. The fact that Payen 

 in 1844, had demonstrated that the cell walls of all vege- 

 tables, high or low, are composed largely of one sub- 

 stance, cellulose, tended to strengthen the position of 

 the cell wall as the really essential structure, of which 

 the protoplasmic contents were only subsidiary prod- 

 ucts. 



Meantime, however, the students of animal histology 

 were more and more impressed with the seeming pre- 

 ponderance of cell contents over cell walls in the tissues 

 they studied. They too found the cell to be filled with 

 a viscid, slimy fluid, capable of motion. To this Du- 

 jardin gave the name of sarcode. Presently it came to 



339. 



WILLIAM HKNJAMIX CAItPKXTKR 

 Photographed by Elliot and Fry, Londor 



