[6] Chemical Division, U. S. Department of Agriculture, Bulletin No. 28, p. 101. [7] Not yet described in any publication. Presented at 12th annual meeting of the Association of Agricultural Chemists, Aug. 7th, 1895. [8] Vid. op. cit. 6, p. 100. [9] Cornell University Agricultural Experiment Station, Bulletin 12. [10] (bis. p. 28). Vid. op. cit. 2, p. 15. [11] Bulletin No. 13, Chemical Division, U. S. Department of Agriculture, Part First pp. 85-6. [12] Bulletin de 1’ Association des Chimistes de Sucrerie, 1893, p. 656. [13] Chemical News, Vol. 52, p. 280. [14] Presented to 12th Annual Convention of the Association of Official Agricultural Chemists, Sept. 7th, 1895. [15] Vid. Volume First, p. 411. [16] Vid. op. cit. 2, p. 17. [17] Dragendorff, Plant Analysis. [18] Vid. op. cit. 6, p. 96. [19] Journal of Analytical and Applied Chemistry, Vol. 7, p. 65, and Journal of the American Chemical Society, March 1893. [20] Vid. op. cit. 16. [21] Vid. op. cit. 6, p. 99. [22] Vid. op. cit. 6, p. 103. PART SECOND. SUGARS AND STARCHES. =44. Introduction.=—Carbohydrates, of which sugars and starches are the chief representatives, form the great mass of the results of vegetable metabolism. The first functions of the chlorophyll cells of the young plant are the condensation of carbon dioxid and water. The simplest form of the condensation is formaldehyd, CH₂O. There is no convincing evidence, however, that this is the product resulting from the functional activity of the chlorophyll cells. The first evidence of the condensation is found in more complex molecules; _viz._, those having six atoms of carbon. It is not the purpose of this work to discuss the physiology of this process, but the interested student can easily find access to the literature of the subject.[23] When a sample of a vegetable nature reaches the analyst he finds by far the largest part of its substance composed of these products of condensation of the carbon dioxid and water. The sugars, starches, pentosans, lignoses, and celluloses all have this common origin. Of many air-dried plants these bodies form more than eighty per cent.