34 



WILD AND CULTIVATED COTTONS 



Spiral 



twistings. 



Stomata 

 of cell- 

 wall. 



Measure- 

 ments. 



Varia- 

 bility. 



means uniformly deposited. It may in fact be noted that here and 

 there the cell -wall is so thickened as to almost obliterate the cavity, 

 thus occasioning what may be called cavernous spaces within the 

 cell, and these are naturally most conspicuous near the base or 

 thicker end of the cell. 



The Cell-wall The wall usually occupies from one-third to 

 two-thirds of the diameter of the cell. In the case of dead cotton, 

 however, it may be so thick as to practically cause the lumen to 

 appear as a thin tube. When critically and minutely studied the 

 cuticular wall is found not to be homogeneous, but to consist of two 

 irregular layers transversely striated. 



The longer the cells, the more uniformly are the deposits thrown 

 down. That is to say, the thinner portions are smaller, more 

 numerous and more equidistant, hence the greater abundance of the 

 spiral twistings. 



Conversely, the shorter the cells, the thicker they become ; that is 

 to say, the coarser the cellulose deposits, the thicker the cell-wall 

 and the fewer and longer the twistings. 



Eecently an exceedingly interesting discovery has been made by 

 Mr. H. de Mosenthal (see ' Jour. Soc. Chem. Ind.,' March 1904) 

 namely, that the cuticular wall is pierced by minute stomata 

 leading into the lumen of the fibre. These stomata, hitherto 

 unobserved, would offer an explanation of the way moisture, and 

 with it tinctorial reagents, penetrate to the interior of the cell. 



Cell Measurements. The measurements of cotton are so inti- 

 mately dependent on variable circumstances that at present even 

 approximations to averages are of greater value than individual 

 results. The variation in length and thickness of the staple is not 

 only immediately governed by the species or variety of plant from 

 which obtained, but even by the race or stock of each such variety. 

 Hence, having secured a definite stock, the results obtained cannot 

 be looked upon as constant, in one locality as compared with 

 another, because of the staple being immediately influenced by 

 the climate, soil, and season of production. Nor in fact can 

 constancy be looked for even in the same locality, since abnormal 

 climatic conditions will instantly disturb the results attainable. It 

 follows, accordingly, that climatic and seasonal variations have to 

 be standardised. 



Dr. Bowman very truly observes that it is a well-known fact that 

 from year to year, in any class of cotton, such as Egyptian, the degree 



