234 ON A NEW REAGENT FOR DETECTING SUGAR. 
cesses is of such simple execution as to be readily adopted 
by the medical profession. I now present chemists and 
physicians with a test-paper, or rather tissue, by means of 
which the presence of the smallest quantity of sugar can 
be detected in an instant. 
The action of chlorine upon sugar is very imperfectly 
known, and the experiments which I have made with the 
endeavor to throw some light upon this question have made 
known numerous inaccuracies in the statements made by 
the most celebrated chemists. Thus, whatever M. Liebig 
may state to the contrary, chlorine acts, even in the dry 
state, upon sugar; it does not require a temperature of 
212° to determine the reaction. At the ordinary tempera- 
ture it requires more time. In all cases there is formed a 
brown substance, which is partly soluble in water — a cara- 
mel, which is of a brilliant black color when dried. What 
is obtained with chlorine is obtained as easily, if not more 
so, with the chlorides, and especially with the perchlorides. 
All the sugars behave like cane-sugar towards the chlo- 
rides; they all experience this dehydratation, the result of 
which is the brownish-black product. And this is not all ; 
as might have been foreseen, the substances of analogous 
composition to that of sugar, and which like it may be 
represented by carbon and water, equally experience the 
same kind of alteration. Lignine, hemp, flax, cotton, paper 
and starch are thus circumstanced. 
From these facts we learn the conditions under which we 
must place ourselves in order to obtain a paper, or rather 
solid band, coated with a reagent capable of detecting the 
presence of sugar. Let us suppose, in fact, a slip of solid 
substance, which is not altered by the chloride of tin even 
at a high temperature ; cover this substance with a layer 
of chloride by immersing it in a concentrated solution and 
desiccation ; then dip the strip thus prepared in a very 
dilute solution of sugar, and expose it to a temperature of 
266°-300°F. The part which has been immersed will 
