BOTANIC MATERIA MEDICA. 291 
into dextrin, which substance is called British 
gum. It is also obtained by boiling the starch 
in dilute sulphuric acid; by continued boiling, 
glucose or grape sugar is the result. 
The sago (from the metroxylon sagus and 
other palms), commonly known as the pearl sago, 
atrow-root (from the rhizome of the Maranta 
Arundinacez), and tapicoa or cassava starch 
(from the rhizome of the Manihot Utilissima) 
are all starches, and are used for delicate arti- 
cles of diet. They resemble the other starches 
as regards acid, boiling water, and their insolu- 
bility in alcohol, ether,-etc. Starch may be 
called the flour of all soft cellular roots and 
grains; for if we wash any well-ground root or 
grain in cold water, then strain the liquid through 
muslin, the starch passes over with the water 
and falls to the bottom in the form of a white 
powder. 
