246 APPENDIX. 
cane sugar, in which it dissolved, excepting a mere trace of a lime 
salt; proving that no true sugar exists in the juice, chemically. 
Samples of Sorghum Sugar.—These, as specimens of the product 
obtained by boiling to the state of a dense syrup the expressed 
juice of the plant, were all impure; differing much, in this respect. 
They exhibited, after repose, some brilliant grains as a deposit. After 
separation, these grains proved to be in large part, transparent, mi- 
nute fragments of pith cells mixed with some crystals, which, contain- 
ing chlorine, sulphuric acid, lime, and alkaline base, were considered to 
be compounds of sugar and alkaline salts. The fluid sugar was, in 
every case, acid, and exhibited a strong tendency to ferment, after it 
had becn afew hours mixed with water. It was, therefore, in every 
case subjected to the usual process of refining before the application 
of the tests was made. Neither of the samples, when subjected to 
the tests which have been named, exhibited any traces of true sugar ; 
and the characters of solubility, and freedom from tendency to crys- 
tallize, place the fluid sugar obtained in the usual way, among the fruit 
sugars, as varieties of glucose. 
After long exposure to air, the pure glucose, chemically obtained, 
forms mammilary concretions made up of radiating prisms, and then 
becomes the variety of glucose called dry fruit sugar : adding another 
distinctive character of fruit sugar. 
I purposely excepted from my trials all unripe or decayed stalks. 
Some subsequent observations show that the unripe stalks afford much 
saline matter which mixes with the syrup. 
When we consider the definiteness and reliability of the chemical 
tests for glucose, the clear and certain manner in which they distin- 
guish all its varieties from ordinary sugar, we may conclude that, as 
far as physical and chemical means permit, the question in relation to 
the kind of secretion in the sorghum of the northern states is settled. 
This plant cannot, by any known process, be made to yield any other 
saccharine matter than glucose, and there is no method known to 
chemists by which glucose has been converted into sugar. 
Generally, those persons skilled in the manufacture of sugar from 
the maple sap, who have failed in producing sugar from the sorghum, 
have attributed their want of success to a difference of composition in 
