BULLETIN OF THE BUSSEY INSTITUTION. 459 
number of tests made in this laboratory on products of the 
hydrolysis of cotton and woods of various kinds. Moreover, 
the rotation here exhibited by the matter insoluble in alcohol 
(quasi(a) D = 55°.25) is much nearer that of pure dextrose than 
had been observed in this laboratory in any previous instance 
where analogous materials were tested. But in the previous trials, 
the condition under which the hydrolysis of the cotton had been 
carried out were less closely akin to those commended by Flechsig 
than in the present instance, where his method of procedure was 
copied as closely as possible. 
It would appear, therefore, that Flechsig’s method of hydrolyz- 
ing cotton, by means of acid of special strength, has real merit, 
although the conversion of cellulose to dextrose may perhaps 
never be so nearly complete as he was led to believe. 
II. The following trial was meant at first to be in precise imi- 
tation of the work of Winterstein,* though the method finally 
adopted differs from his in that lead carbonate was here used to 
neutralize the acid product of the hydrolysis : — 
0.9302 grm. of worn cotton cloth, dried at 100°, were rubbed 
up with 5 grm. of sulphuric acid of 92.5% H,SO,, and allowed 
to stand during 12 hours. After diluting with water, the brown 
solution was thrown upon a tared filter which retained nothing. 
The solution was made up to 200 c.c. and boiled during two 
hours. A sediment formed which, on being collected, washed, 
dried and weighed, was found to amount to 0.043 grm. The 
clear filtrate was neutralized with lead carbonate. After filtration 
sulphuretted hydrogen gas was passed to remove any dissolved 
lead, and the solution was filtered and boiled to remove the excess 
of sulphuretted hydrogen. On being tested with Fehling’s liquor 
sugar enough was found to amount to 52.34% of the dry cotton 
taken, or to 54.87% of that cotton, if we subtract from the 
weight thereof the weight of the small quantity of insoluble 
matter that was deposited during the hydrolysis. These last 
figures correspond to 49.4% of the theoretically possible dextrose 
(111.1) which might be obtained from 100 parts of cellulose if it 
were practicable to change the whole of it to dextrose. The rota- 
tory power of the solution was found to be quasi(a) D = 125°.2. 
The larger part of the solution was evaporated to the consist- 
* Die landwirthschaftlichen Versuchs-Stationen. 1892, 14, 383. 
