286 ON THE MANUFACTURE OF ARTIFICIAL GUM . 
templated. I shall allude to this presently, but would first 
observe, that there appears to be one disadvantage attending 
this form. Some intelligent persons were apprehensive 
that, taking advantage of the resemblance, exotic gum 
would be adulterated with artificial gum; fortunately this 
is impracticable, as the smell and taste of potato oil, which 
is always given out by artificial gum, are sufficient to betray 
its presence; and thus, if the purchaser suspects a fraud, he 
can easily detect it. 
Dextrine may be manufactured either by the use of acids, 
or by means of the diastase contained in malted barley. I 
will examine these various processes in succession. 
By Sulphuric Acid. — The dextrine produced possesses 
the disadvantageous property of being deliquescent, i. e> 
absorbing the humidity of the atmosphere. This method 
is therefore never employed, as, besides this disadvantage, 
the products are often coloured. 
By Nitric Acid. — This method is now most generally 
followed for obtaining dextrine in the state of powder. I 
have thought proper to observe on this head, that the acid 
employed must be perfectly pure, and for this reason — that 
nitric acid, as is well known, is obtained by the decompo- 
sition of nitrate of soda, obtained in the natural state from 
the coast of Bolivia, by means of sulphuric acid; now this 
salt always contains a portion of sea salt, which, together 
with the sulphuric acid and nitric acid, generates chlorine. 
Although but a small portion of this chlorine is contained in 
the acid, and consequently in much less proportion in the 
dextrine produced by that acid, it is nevertheless sufficient 
to considerably diminish the brilliancy and depth of the 
colours prepared with the dextrine. Several printers upon 
paper and fabrics have observed this, without being able 
to account for it otherwise than by attributing it to the 
inferior quality of the gum. 
By Hydrochloric Acid. — This process is only employed 
to my knowledge by Messrs. Saint Etienne, who first render 
