BULLETIN OF THE BUSSEY INSTITUTION. 463 
Some conclusions to be drawn from the foregoing experiments 
may be stated as follows : — 
I. When strong sulphuric acid is made to act upon cellulose, 
and the product is subsequently boiled in dilute acid, it is not 
true that the whole of the cellulose may readily be changed to 
dextrose. The statements made in relation to this subject in 
most chemical text-books are faulty in several respects. 
Il. It is a well-known fact that when strong sulphuric acid is 
made to act upon carbohydrates, — that is, upon starch, sugars, 
dextrins, or cellulose, — compounds of the carbohydrate and the 
acid are formed. At one time or another these compounds have 
been called by several different names, —for example, vegeto- 
sulphuric acid, sulpholignic acid, sulphoglucic acid, dextrose- 
sulphuric acid, cellulose-sulphuric acid, etc.,*— and it has been 
held not uncommonly that they may be decomposed pretty thor- 
oughly by the long-continued boiling in diluted acid which occurs 
in the actual process of hydrolysis. In point of fact, it is by no 
means an easy matter to decompose these compounds completely 
by way of hydrolysis. As a general rule, no inconsiderable part 
of the organic matter with which the strong acid united at first is 
not changed to dextrose when boiled subsequently in the diluted 
acid. Some part of this undecomposed matter remains admixed 
with the dextrose-syrup, and, in experiments such as have been 
described above, it must necessarily tend finally to contaminate 
the solid dextrose obtained from the syrup. 
III. In spite of the fact that solutions of salts of the above- 
mentioned compounds of a carbohydrate and strong sulphuric 
acid are highly unstable, it appears to be by no means easy to 
decompose such solutions completely. Even after long-continued 
boiling of dilute solutions of the calcium or barium salts of these 
copulated acids, some portions of the salts are apt to escape 
decomposition and to contaminate the dextrose syrups. When 
strong alcohol is added to such syrups any remnants of the 
sulpho-salt which may be present will remain undissolved by the 
* Compare Braconnot, Annales de Chimie et de Physique. 1819,12.173. 
Peligot, 21d. 1838, 67. 1138. Blondeau, Journal fiir praktische Chemie. 
1844, 32. 429. Fehling, Annalen der Chemie und Pharmacie. 1845, 
53. 134, and 55. 13. Hoenig und Schubert, Monatshefte fiir Chemie. 
1885, 6. 708. 
