iv THE COTTON FIBRE 87 



Lint-length. The " length " of the lint is also a 

 complex of several factors. Chief amongst these are the 

 mean maximum length, and the regularity. 



Some strains of cotton produce lint-hairs of the same 

 length on all parts of the seed-coat. Most kinds, however, 

 make shorter hairs, at the micropylar end.* 5 Fluctuation 

 in this respect does not seem to be very noticeable, and 

 we can restrict our present remarks to the mean maximum 

 length ; this is ascertained by combing the lint on the 

 seed, and measuring from the seed to the edge of its 

 halo of lint. 



Fluctuation in the mean maximum length is described 

 later, and the relation of such fluctuation to the conditions 

 under which the fibre develops has already been discussed. 

 Briefly summarised, this length is determined primarily by 

 the constitution of the individual plant ; secondarily, by the 

 experiences of the particular seed and boll during the first 

 four weeks after flowering. 



The second determinant necessarily varies greatly when 

 we are dealing with a commercial sample which includes 

 seed from bolls of various ages ; the particular experiences 

 of each boll may be so different that on the average we 

 may consider the effects from year to year as being almost 

 uniform. Consequently, though it is possible to depress a 

 40 mm. lint to 30 mm., we find that the practician draws 

 a sharp distinction between 30 mm. and 40 mm. 

 varieties. 



We have now completed an outline sketch of the 

 principal factors which are yet known to control the 

 development of a cotton plant in Egypt, and certain 

 hypothesis have been propounded which serve for the 

 present as interpreters of the author's data. 



It might seem that too much -stress has been laid, 



* Photos. 



