88 THE DEVELOPMENT OF KAW COTTON 



water shortage, would presumably act in a proportion- 

 ately less severe way. Thus, bolls which were young 

 when deprived of water would not make lint of the full 

 length, but the lint might be subsequently thickened 

 normally if normal water-supply were restored. Con- 

 versely, bolls which were three-quarters grown at the same 

 time would not thicken their lint normally, but the length 

 of the lint, having already been established under preced- 

 ing normal conditions, would be normal and unaffected. 

 We will now proceed to see how far evidence obtained 

 in this way at Giza will carry us. 



Two complete series of data have been obtained. The 

 first covers sixty days in succession during 1912, on a plot 

 of wide-sown No. 77, which was purposely 

 subjected to severe water shortage; the 

 second covers ninety successive days in 

 1913, on a group of plants of the same strain, growing 

 in field crop conditions on excellent land, with cultiva- 

 tion as nearly perfect as it could be, and producing a crop 

 from this particular plot of roughly 700 pounds of lint to 

 the acre (if allowance is made for some 150 pounds of lint 

 damaged by a very severe boll- worm attack). It will be 

 seen later that the attack of this pest made no difference 

 to the behaviour of the lint, so long as lint from obviously 

 damaged locks was excluded from examination. 



One difficulty presents itself the dating of the jpolls. 

 Since there is a definite amount of fluctuation in the 

 length of the maturation period, there must be uncertainty 

 as to the exact stage of development of the old bolls if we 

 group them by the date of flowering, and conversely there 



