MOHL, AND THE FIRST USE OF THE WORD PROTOPLASM. 29 



time, several cytoblasts originate in the interior of each of these 

 cells, and generate new cells, on the rapid expansion of which 

 the parent cells also cease to be visible, and become absorbed. 

 The same process is repeated indefinitely " (p. 253). From all 

 this it is not difficult to see that, without full appreciation of 

 the fact, his mind being occupied with the idea of cell-form 

 his observations of nature are in harmony with the doctrine 

 that all these granules, nucleoli, and cytoblasts are masses of 

 living matter directly descended from pre-existing living mat- 

 ter, furnished by the germ, and which not only form but sustain 

 all the vital processes in the formed cells. 



The next contribution to the subject is one of particular in- 

 terest as here for the first time we meet with the word proto- 

 plasm. It consists of a memoir by Hugo von Mohl, first pub- 

 lished in 1844, but we may give an analysis of his views taken 

 from his later work on the " Vegetable Cell," 1853, p. 36. 



;< If a tissue composed of young 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 wall of the cells in the form of a closed vesicle which be- 

 comes more or less contracted and consequently removes all the 

 contents of the cell, which are enclosed in this vesicle, from the 

 wall of the cell. Reasons hereafter to be discussed have led me 

 to call this inner cell the primordial utricle. Iodine colours 

 it yellow, and it is therefore probably always nitrogenous. 

 Cellulose cannot be found in it, and the compound of which it 

 is composed is as yet unknown. The primordial utricle disap- 

 pears again with the thickening of the walls, of the vessels, the 

 cells of the wood, of the pith, of the inner part of the petioli, 

 and of thick leaves. ... In the centre of the young cell, with 

 rare exceptions, lies the so-called nucleus of Robert Brown. 

 .... The remainder of the cell is more or less densely filled 

 with an opaque viscid fluid of a white colour having granules 

 intermingled in it, which fluid I call protoplasm. This fluid is 

 coloured yellow by iodine, coagulated by alcohol and acids, and 

 contains albumen in abundance, whence young organs are 

 always very rich in nitrogen. . . . During the growth of the 

 cell, irregularly scattered cavities are formed in the protoplasm ; 



