16 SPECIES OF FECULA EMPLOYED IN PHARMACY. 
ART. IV.—OBSERVATIONS ON SOME OF THE SPECIES OF 
FECULA EMPLOYED IN PHARMACY. By F. V. Raspail. 
Extracted from his Nouveau Systeme de Chimie Organique. 
We have translated from the above mentioned work the 
researches of Raspail, as regards the microscopic characters of 
the most prominent feculge. The difficulty of detecting 
admixtures of these substances, which are of frequent oc- 
currence, renders it necessary that all the means of discrimi- 
nation should be familiar to those who are liable to imposi- 
tion. With the aid of a microscope of moderate power, the 
size, form, and organization of the grains of fecula can be 
sufficiently determined, and as these will be found to vary in 
each species, it affords a method of investigation which may 
be employed whenever doubts exist of the genuineness of an 
article. For the information elicited by these researches of 
Raspail, pharmacy is not a little indebted, as a flood of light 
has been thrown upon a hitherto obscure department, in 
which even the most practised are liable to be deceived; and 
we are certain that by placing it at the command of our 
readers, benefit will be experienced in their professional trans- 
actions. 
Potato Fecula. 
{Solarium tuberosum,) PI. fig I. This fecula assumes 
forms the most varied, and no other known kind possessess 
dimensions as great. When fresh, there are observed, upon 
the surface of the grains, concentric rugae, which often dis- 
appear by dessiccation. The largest attain the size of g of a 
millimetre, the remainder vary from the T \ to the ^L; they 
are oval, formed in concentric cocoons, gibbous, obscurely tri- 
angular, rounded and spherical, at least those of the smallest di- 
mensions are. The potato is the only plant of which the fecula is 
used for ordinary culinary preparations; it is that which is of 
least value. To extract it, the tubercles are washed in water 
and scraped, they are then rasped, placed upon a sieve, and 
