ENVIRONMENT OF THE BOLL 97 



the water was given, the more time they had to recover 

 from the poisoning effects of water -short age in the hot, 

 dry climate of Egypt, and the more opportunity they 

 had to decompose the poisonous substances which are 

 believed to te formed in the cells. As the amount of this 

 poisonous substance decreased in successive flowers, the 

 lint grew up more nearly to its full length, but as we 

 shall see in the Daily Picking Series of 1913 did not 

 reach it before the soil began to dry up again, and from 

 August 11 the length therefore began to fall. 



The full significance of this poisoning effect has yet to 



be worked out, and it would seem that cotton-lint is most 



suitable material for the purpose. Herein 



j tility of cons i s t s one of the principal utilities of pure 

 Pure Strains. 



strains : If they do not produce the product 



which we know they are capable of giving us, we can 

 recognize the fact at once, and can search for the cause. 

 The whole behaviour of No. 77 in this Dated Flower 

 Series was rather that of a good strain struggling under 

 adversity; it was prevented from reaching its normal 

 behaviour by the poisoning effects brought about through 

 water -short age. 



The main feature of these curves remains to be dis- 

 cussed. We have seen that they represent the behaviour 



of a cotton-plant under severely adverse con- 

 Length and 



Strength due ditions, and that there is no significant con- 

 to the Same nection between the properties of length and 

 es ' strength in the lint from any given boll. In 

 spite of this the movements of one curve can be used to 

 forecast the other, so that, if we know the breaking strain 



7 



