PREFACE. 



It is necessary in considering the results collected together in 

 the following pages to remember that they very probably cannot 

 be applied without modification to results collected elsewhere, unless 

 the conditions in both places are very closely similar. Differences 

 in climate are likely to upset the ratios of growth in the plant, and 

 insect, of emergence of the moths, and of boll-setting and maturing. 

 In places like Madras, where resting stage larvae do not occur, condi- 

 tions are obviously so different that no harmony need be expected. 



It appears also evident that differences in the variety of cotton 

 grown are likely to upset the agreement between results. 



Varieties setting seeds larger or smaller, more or fewer are likely 

 to give results disagreeing from those set out here. It is even possible 

 that climatic variations from year to year combined with the con- 

 tinual change that is going on in any variety of cotton might cause 

 later results to be slightly out of harmony. The whole investigation 

 is still very much in the pioneer stage, and it is impossible to predict 

 at present its final direction. No finality is claimed for the results; 

 they may have to be modified when more material has been examined. 



I take the opportunity to thank DE. HURST, Controller of the 

 Physical Service, and ME. CUEEY of the Physical Service for having 

 helped with suggestions, criticism and corrections, which were most 

 valuable in the presentation of the observations. 



The manual work of examination of samples was completed before 

 the theoretic digestion was undertaken, and was done by men who 

 had no knowledge whatever of the object of the research. 



