332 ANNUAL OF SCIENTIFIC DISCOVERT. 



aided by chemical tests, the presence and kind of sugar in the tissues, or sap 

 of a plant, often without incurring the risk of change of properties through 

 the chemical means adopted for withdrawing the sugar, 



We have the authority of our associate, Mr. Spraguc, for the conclusion, 

 that the Sorgltum rnljare, or saccharatum, belongs to the tribe including 

 grasses, and we should therefore expect to find its saccharine matter the 

 variety of glucose called sugar of grasses or fruit sugar. The unsuccessful 

 attempts made to crystallize sugar from the juice of the Sorghum, produced 

 in different climates of our country last year, indicated that it contained no 

 cane sugar, or that the presence of some detrimental matter in the ex- 

 pressed juice, destroyed the crystallizable character of cane sugar, as can bo 

 artificially done. My observations commenced after I had obtained several 

 specimens of the Sorghum, and have been continued on the semifluid 

 sugar, likewise from different parts of the United States, with uniform 

 results. 



When a recent shaving of the partially-dried pith of the matured stalks of 

 the Sorghum is examined by the microscope, we observe the sugar cells 

 filled with semifluid sugar. After exposure to air it is often possible to dis- 

 tinguish some crystalline forms in the fluid sugar. These grains, after being 

 Avashed, cease to present a clear crystalline character, and have the hard- 

 ness and general appearance, of dry fruit sugar. By withdrawing the sugar 

 without the aid of water, it is possible to obtain it colorless and neutral, as a 

 semifluid glucose or fruit sugar, and no traces of crystals or crystalline forms 

 can be seen. The glucose thus obtained, freely exposed to air, soon under- 

 goes the molecular change which is exhibited by sugar of grapes, and we 

 thus observe another character associating the whole product, with the sugar 

 of grasses and fruits. Leaving the physical observations, and substituting 

 the more exact processes of the laboratory, I found that the semifluid sugar 

 of the Sorghum did not blacken in sulphuric acid, but was sensitive to the 

 action of alkalies, and reduced the alkaline solution of tartrate of copper, 

 thus conforming to the well-known characters of glucose. The most care- 

 ful trials I could make, failed in detecting cane sugar in any samples of the 

 Sorghum stalks, or in the samples of sugar, including one made by Colonel 

 Peters in Georgia, prepared under the most careful management. I must 

 therefore conclude, that the Sorghum cultivated in this country does not secrete 

 cane sugar or true sugar ; its saccharine matter being purely glucose in a semi- 

 fluid form. 



As a matter of science this result is interesting, in showing the integrity 

 of character pertaining to the genus in which this plant is botanic-ally 

 placed; the sweet grassed yielding fruit sugar, while the maize produces 

 cane sugar only. 



In its economical bearings we might wish that the sorghum secreted cane 

 sugar, for the values of cane sugar and glucose are very different. From 

 the best authorities we learn that the power of imparting sweetness in cane 

 sugar, is between two and one half and three times as great as that of dry 

 glucose, and the semifluid sugar of the Sorghum containing water, nearly 

 four pounds of this will be required, to equal one pound of sugar in ordinary 



