Now this statement is interesting as showing one or two important features. The weight of the seed is seen to be nearly a quarter of the whole plant, while the stems and leaves together take up nearly one half. A very small proportion by weight of the plant is taken by the lint.
A chemical analysis of the mature Cotton plant yielded the following substances:--
Water. Potash. Ash. Lime. Nitrogen. Magnesia. Phosphoric acid. Sulphuric acid. Insoluble matter.
Of ten analyses made with the cotton lint (which takes up about 10-1/2 per cent. of the whole) M'Bryde states that the average amount of water found was 6.77, ash 1.8, nitrogen .2, phosphoric acid .05, potash .85, lime .15, and magnesia .16.
He very pertinently remarks also "that if the lint were the only part of the plant removed from the land on which it is grown, cotton would be one of the least exhaustive of farm crops. The only other part which need be permanently lost to the soil is the oil, which also contains very small amounts of fertilising constituents." In connection with this he further says "that even when the seed is taken away along with the lint, cotton still removes smaller amounts of fertilising materials from the soil than either oats or corn." It should be borne in mind that the soil upon which cotton is cultivated lies fallow for a greater part of the year, and the fact of absence of cultivation, with consequent non-fertilising and non-enriching of land, must tend in the direction of soil exhaustion by the Cotton plant.
Another useful and important fact in connection with the Cotton plant is the medicinal use to which the roots are put. According to the _American Journal of Pharmacy_, the bark from the roots of the Cotton plant contain an active ingredient which in its effects is very much like ergot.
Chemical investigations have conclusively proved that the ripe fibre of the Cotton plant is composed of the following substances:--
Carbon, Hydrogen, Oxygen, and they tell us that when cotton is fully ripe it is almost pure cellulose.
Dr. Bowman has pointed out that the percentage of water in cotton fibre "varies with different seasons from 1 to 4 per cent. in the new crop, and rather less as the season advances. Above 2 per cent. of moisture, however, seems to be an excessive quantity even in a new crop cotton, and when more than this is present it is either the result of a wet season and the cotton has been packed before drying, or else it has been artificially added."