1Q 



MULTIPLICATION OF CELLS. 



n 

 Paper, 



3rd. By the tenacity of its structure, and the looseness of its parts, to bind the 

 component parts of the plant together, and to increase its elasticity. 



4th. It has for thousands of years been of great use to man for various eco- 

 nomic purposes : 



First, in the form of papyrus, or the paper derived from the stem of a rush of that 

 name, and employed as such by the ancient Egyptians, Grecians, and Eomans, until 

 long after the birth of Christ. In a similar way it is still used by the Chinese, 

 and by them is derived from the pith of a plant (JEschynomene Fig. 48), which 



they cut into very thin slices. This material 

 lends a charm to Chinese drawings, since its cellu- 

 lar character enables it to absorb the colour- 

 ing materials in great abundance. 



Secondly, as a textile fabric. The mummy-eloths 

 of the Peruvians, who existed long before the era 

 of Montczuma and the Spanish invasion, are com- 

 posed of this tissue only. At the present time we ob- 

 tain cotton (Fig. 62 B) chiefly from America, where 

 it is derived from the seeds of the cotton plant (Gos- 

 sypiuin). It is far less resisting and durable than 

 woody fibre or linen ; but its comparative abun- 



!. Section of the Chinese rice- dance, low price, and easy working have obtained 

 , or JSschymomene, showing large m, -.-, -, 



cells with a scattered deposit. for it great favour. The present war with Russia 



will probably induce a determination to use the cotton cell to the still greater exclusion 

 of the woody fibre ; and it has recently been shown in America that ropes made 

 of cotton are far stronger and more durable than has hitherto been believed. 



Paper is made from the manufactured cotton, and also from the refuse part of the 

 raw material. 



Multiplication of Cells. It is not within the limits of this essay to enter upon 

 the interesting question of the production of cells ; but we may state that a common 

 mode is that of division of the cell into two or more cells. This is effected in the fol- 

 lowing manner : First, there is an aggregation of the con- 

 tents of the cell around the nucleus, whilst the nucleus 

 manifests a disposition to divide itself into two by a line 

 of construction on either side. Secondly, the cell- wall is 

 bent inwards towards the point of division of the nucleus, 

 and by degrees insinuates itself between the two parts of 

 the nucleus as the division of the latter proceeds, until at 

 length the cell- walls from opposite sides meet at the centre 

 of the nucleus, and the nucleus is divided, and two cells pro- 



luced. Each of the new cells contains half the original Fig . ^.-various stages of de- 

 Mis, which now constitutes the nucleus of each cell ; velopment of the HJBMATO- 

 and after a period it is prepared to subdivide and to form 

 another cell, and thus progressively, so long as the vital 

 process lasts. In this way it is conceivable that an im- 

 mense multitude of cells may be produced ; and should the d, a divided cell again repeating 

 division be speedily effected, we may form a conception of thc process of subdivision - ^ 

 the astounding fact, that in some of the fast-growing cellular plants as the mushroom 

 -the cells have been produced at the rate of sixty-six millions in a minute. 



C t Vl ccus , 



the%%?eparing to divide. 



