1452 FIBRE CROPS 



The vegetative period of the plant extended over 174 days, the seeds 

 being sown on May 7th. Analj^ses were made at four different times : 

 i) When the flower buds first appeared (June 7th). 



2) At the beginning of flowering (September 22nd). 



3) At the first picking (September 29th). 



4) After the death of the plants, which was caused by the morning 

 frosts (October 28th) . 



The first two analyses were made on the whole plant ; in the last two 

 the following parts were analysed separately : hairs (lint), seed minus its 

 coats, seed coat, iinripe capsules, fruit coats, stems and leaves. 



The maximum growth of the plants is reached at the time of the first 

 picking the average weight of a single plant being 196.67 gm. when green, 

 and 82.10 when absolutely dry. When the plant dies the weight decreases 

 on account of dessicaticn and the loss of parts of the plant, the average 

 green weight then being 116.93 and the dry weight 54.69. 



The percentage of water in the green weight gives an unexpected re- 

 sult in comparison with other plants; this percentage is greater at the beginn- 

 ing of flowering than when the flower buds appeared (80.89 agains 73.81) ; 

 in the two later periods it was 58.25 and 52.23 respectivel3^ A possible 

 explanation of this lies in the fact that in the early stages of development 

 cotton is sensitive to the harmful action of the salts in the soil. Yet ano- 

 ther explanation may be that during the flowering period the plant needs 

 much water to promote an active circtdation of food materials. 



The appended table sums up the anal3^ical results. This table, toge- 

 ther with others, which are given in the text of the paper, show that the chief 

 modifications occurring in the cotton plant during the various stages of 

 its development are as follows : 



i) As time goes on, there is of reduction in the relative amounts of 

 nitrogen, nicrogen-free extracts and ash ; the maximum amounts of ash and 

 N - free extract occur in the green parts of the plant. 



2) The percentage composition of the ash shows that cotton demands 

 potash more than anything else, then lime, and finally phosphorus. The 

 ash also contains large amounts of chlorides and sulphates, the substances 

 which work the greatest harm to the agriculture of the district. The plant 

 fights against this harmful action by developing its vegetative organs ra- 

 pidl^^ 



3) As the plant develops there is an accumtdation of raw cellulose 

 and pentosans, which form the cell walls. 



4) The analysis of the cotton itself, by the methods adopted by I. 

 KoNiG, Gross and Bevan justifies the hypothesis that it is not pure cel- 

 lulose, but a mixture of cellulose and hemi-cellulose. For cotton of the first 

 quality, the composition is 71.190 per cent cellulose (a cellulose) and 21.355 

 per cent (^ cellulose). 



5) The green parts of the plant and the seeds contain a high percen- 

 tage of fats, and the greater part of the percentage in the whole plant oc- 

 curs in these parts. 



Taking the ash analysis as a basis, and reckoning 21 680 plants to the 



