735 



the analyses reported. Tabulated data for nitrogenous matter and ash 

 in wheat and oats at different stages of growth (April 18 to August 6) 

 during ;") years (1876, '77, '78, '81, '90) show that the amounts of these 

 ingredients are very high at the outset (ash, highest found, 12.75 per 

 cent; nitrogenous matter, highest found, 33.56 percent) and constantly 

 diminish as maturity advances. Determinations of tannin substances 

 and gums in oats at different stages are also tabulated, showing a 

 similar decline with the advance of maturity. 



When the growth of the roots has reached a certain point the stem and 

 leaves develop and the action of chlorophyll commences, carbonic acid 

 gas is decomposed, and the carbon is fixed in the form of carbohydrates. 

 These carbohydrates are believed to be in every case polymers, more or 

 less advanced, of formic aldehyde. This polymerization accounts for 

 all the carbohydrates in cereals — glucose, saccharoses, dextrine, starch, 

 and cellulose — as well as for the two recently described materials, the 

 vasculose of Deherain and straw gum {gomme de paille) isolated by the 

 author.* The percentages and yields per hectare of cellulose and straw 

 gum in wheat and oats at different periods of growth (May 13 to August 

 G) are tabulated for three seasons (oats 1877, wheat 1881 and 1890). The 

 proportion of these substances increases rapidly at first and then more 

 gradually to the end of the life of the plant. The increase in the case 

 of straw gum was from 3 to 20.21 per cent in oats and from 8.32 to 31.89 

 per cent in one instance in wheat. From these data the anthor states 

 the order of development in the early life of cereals as follows: 

 (1) Assimilation of nitrogenous and mineral matter; (2) chlorophyll 

 action which produces those bodies which are changed by a very active 

 resinration into gums, tannin, and vegetable acids; and (3) the assimila- 

 tion of the carbon in the carbonic acid of the air, resulting in the jiroduc- 

 tion of the higher carbohydrates — cellulose, straw gum, and perhaps 

 vasculose. 



The processes of the maturing period now commence when the root 

 is sufficiently developed and firmly fixed in the soil. The carbohy- 

 drates elaborated by the foliage are gradually converted into starch, 

 the proportion of which steadily increases as maturity advances. It 

 is shown, however, that this metamorphosis does not extend to the 

 cellulose and straw gum except at the beginning of this period. The 

 ph>/,iological changes which now go on in the plant are very suscepti- 

 ble to unfavorable influences of temperature, moisture, etc. The final 

 product of the vital activity of the plant is starch, the proi)ortion of 

 which largely determines the quality of the crop, and is itself deter- 

 mined by the climatic conditions. This may be seen by comparing 

 analyses of wheat grains grown in 1889, when the season was very dry, 

 with the analyses of that gTowu in 1888, when the weather conditions 

 were normal. 



'Etude de la xiaille; Aun. Agron., 16, p. 358; Compt. rend., 110, p. 97. 



