lit 



As a result of my investigations t will say that tho development o? sucrdsid in sor- 

 ghum is an accidental function, or rather an adventitious function. It goes on u.su- 

 ally pari passu with the formation of the starch in tho grain and the content of su- 

 crose in tho plant, and its quantity is at a maximum at the time the starch formation 

 is completed. In tho sugar-cane the sucrose appears to be not only reserve, but also 

 plastic material. In the upper part of the cane the content of sucrose is much less 

 than in the lower, showing that in the region of most active growth the sucrose may 

 suffer decomposition and help in the formation of proteid. (I wish to add here that 

 the only way in which the plant can use sucrose for the formation of other bodies or 

 for working it into living tissues is by thus getting it into protoplasm.) On the other 

 hand, the content of sucrose in sorghum is sensibly the same in all parts of the cane, 

 being just as gre.it at the top near the place of most rapid starch storage, as it is near 

 the base. It is not strange, therefore, if it be true that the production of sucrose is 

 only tho expression of the exuberant vitality of the leaf of the sorghum, that the 

 greatest variations should be met with the content of sucrose. These variations are 

 not confined to different varieties or to different fields, but are found in the same va- 

 riety in different canes growing in the same hill, and which, therefore, have been 

 subjected to precisely the same conditions of culture and weather. 



In ten successive analyses of sugar-beets made two years ago, I found no greater 

 variation than 1 per cent, in sucrose. The same was true of ten successive analyses 

 of sugar-canes I made last month, November, 1886. On the other hand, any ten suc- 

 cessive analyses of sorghum-canes, made last October, will show a variation of 6 per 

 cent. 



I have not the time here to cite all the instances I have noticed which illustrate the 

 principles set forth above. They number hundreds. Without a record of these 

 analyses, however, the fact clearly appears that the chief cause of variation is found 

 in the accidental or adventitious nature of the formation of the sucrose ; in other 

 words, its independence of the life history of the plant. When, however, the sncrose 

 has once been formed, as in a mature cane, it is subject to sudden variations. Sudden 

 changes in the weather, severe frosts, followed by warm weather, or simply standing 

 dead ripe, often cause a rapid disappearance of the sucrose. It is first converted into 

 invert sugar and this quickly disappears by fermentation. 



When the canes have been cut also, if they be expressed at a temperature of a warm 

 September day, the sucrose is rapidly inverted. This inversion is not due to the ac- 

 tion of the acids which the sap contains, but is produced by a special ferment, proba- 

 bly invertin, or some similar substance. 1 



These variations in the content of sucrose are, as I intimated at the beginning, tho 

 chief obstacles now in the way of the successful introduction of a sorghum-sugar in- 

 dustry into this country. The last one is easily avoided by promptly working the 

 cane as soon as it is cut. The first one can only be overcome by the scientific agrono- 

 mist, aided by the best practical botany and chemistry. 



Since writing the above I have received the Revue Scientifique, of February 5, 

 1887, containing a notice of the observations of Girard on the production of carbohy- 

 drates in plants. This author definitely confirms my statements in respect of the in- 

 dependent formation of sucrose in leaves. The reviewer says : 



"Los exp6riences de M. A. Girard mottent hors de doute que les liinbes fabriquent 

 alors dos saccharoses et des sucres r<5ducteurs." 



M. Girard shows tho possibility of leaves developing starch from sucrose, but there 

 appears to be no evidence that the reverse of this operation takes place. 



YIELD PER ACRE. 



In the experiments of the New Jersey station we have already seen 

 the theoretical yield of sugar per acre. It is a matter of considerable 



1 Ducloux, Compt. rend., KM, p. 881, has shown thatsunlight is capable of mvertiuga 

 solution of sucrose. 



