SCIENCE AND COTTON 305 



cotton is thus the recommendation to grow pure strains, pick 

 the fields at short intervals, and sort the pickings according to 

 class. The real answer is a counter-inquiry as to whether it 

 will pay to do so. The extra labour involved in more frequent 

 picking, the trouble and skilled advice required in classifying, 

 go far to neutralise the advantages, and it may well be the case 

 that it would cost less to continue to take out the short fibres 

 by carding and combing. This is, nevertheless, a very practical 

 and simple reform, but not so simple as some method which 

 should enable any cultivator to watch some feature of his plants 

 as the locomotive driver watches his pressure-gauge, and so 

 keep the growth-processes constant within the ripening fruit. 



This last may appear to be a somewhat far-fetched comparison, 

 but so much precision has been imported into cotton affairs of 

 late years, that such watching has actually become practicable 

 as laboratory technique, and simplification may be confidently 

 expected. 



The reader may notice that this discussion has paid very 

 little attention to the damage wrought by insects and fungi. 

 This is partly because such damage is usually definite, and its 

 effects on the plant are easily ascertained. Partly also because 

 it is unnecessary to emphasise the economic importance of these 

 plagues ; much attention has been paid to them, and is still being- 

 paid. In the stress of the struggle against some pestilent insect 

 one is apt to forget that it can only destroy that which the plant 

 has constructed or would construct. All the damage done to 

 the Egyptian cotton crop by the " boll-worms " in the worst year 

 on record could be restored by the ripening of four additional 

 fruits on each cotton-plant in the country. 1 That insects and 

 fungi are important components of the environment, as " modify- 

 ing " factors, no one would attempt to deny; that disproportionate 

 amount of investigation — though by no means an excessive 

 amount — has been devoted to them, as compared with the 

 plants they act upon, is equally undeniable. The reason is very 



1 1 As this statement regarding the "boll-worm" may appear exaggerated, and 

 as the general point at issue is rather important, the numerical basis may be stated. 

 The average crop of Egypt is lately about 450 lb. of lint per acre. Land giving 

 this yield, with the usual sowing of 12,000 holes per acre, or 24,000 plants, averages 

 16 bolls per plant (contents of each boll weighing 2 grams, or about 07 grams of 

 lint). Total crop of Egypt is about jh million kantars, thus produced by sixteen 

 bolls per plant ; four additional bolls would give nearly 9^ million kantars ; even 

 liberal assessment of damage from boll-worm does not reach 2 million kantars. 



