ORIGINAL COMMUNICATIONS. 
the other; first heat the diluted acid, and add the fecula and 
water, in small quantities at a time, then raise the temperature 
to ebullition, and keep it there a few minutes. Afterwards 
saturate the acid with marble dust; filter, and evaporate care- 
fully to dryness. 
*Thenard says, take one hundred parts of fecula, twenty- 
eight of water, and twenty of acid, which is evidently a mis- 
take, as the quantity of water is entirely too small. The dex- 
trine obtained by the process of Berzelius is very soluble in 
water, and colors vinous red with iodine. According to M. 
T. Thinus, [Journal de Pharm. tome xx,) the following are 
the most eligible proportions: 
Fecula 50 parts. 
Acid 10 « 
Water 600 " 
I have used these proportions in preparing it, and found them 
to answer very well; mix the fecula with one-half of the 
water, and the acid with the other, and apply heat, taking the 
precaution to keep the mixture in constant agitation, at 150° 
or 160° Fahr., the whole becomes a jelly, which gradually 
becomes more fluid, until the temperature arrives at 196°. 
Keep the mixture at this degree for some minutes, and then 
allow it to stand twenty-four hours, when it is to be filtered. 
On adding an excess of alcohol to this solution, the dextrine 
is precipitated in a floculent state, which aggregates in a cohe- 
sive mass. Thus obtained, it retains a small quantity of sulphu- 
ric acid, mechanically, whicb by re-dissolving in a small quan- 
tity of water and again precipitating, yields the dextrine pure. 
This process might be altered so as to saturate the acid with 
marble dust, and evaporate the solution to dryness, after filtering. 
2d. A much easier, and more eligible process is that in 
which diastase is used as the agent. The following propor- 
tions have yielded a satisfactory result, viz. : 
Diastase 1 part. 
Fecula 400 " 
Water 1200 " 
*Traite de Chemie, tome iv, page 371. 
