a 
~ 
- 
BOTANIC PHYSICIAN. - 
drachm into three scruples; and the seruple into twenty grains. 
easures are rejected by the Edinburgh college, but are admitted in | 
armacopcias, and used by the apotiiecaries. They are 
ded in a similar manner, and are made to answer te the specific 
vity of water. -A table-spoonful and tea-spoonful, (measures fre- 
- quently employed), are understood to be equal, the former to half an 
ounce, the latter to one drachm. ; 
N. B. Sixty drops of water, one hundred of diluted alcohol, or an 
hundred and twenty of alcohol, are equal to a drachm, by measure. 
SECTION. II. 
MICAL ANALYSIS OF THE ARTICLES OF THE MATERIA MEDICA. 
_. The consideration of the general analysis of the substances employ- 
ed as remedies, must necessarily precede their particular history, as 
it is so intimately connected with the observations to be made on — 
their properties, the marks of their purity and perfection, their ac- 
on each other, their combinations, and pharmaceutic treat- 
_ CHEMISTRY arranges all bodies under two classes ; those which 
_ are simple, and those which are compound. The former are such — 
as consist merely of similar parts ;- the latter such as can be resolved 
} articles different in their properties from each other, and from 
und which they had formed. From the combinations e 
i few simple substances, origmate all the productions of nature, aM 
all those which are the results of the spevtiins of art. = 
_ It is the province of chemistry to trace these combinations, to de- 
termine whether bodies are simple or compound ; and, if compound, 
to ascertain the number and proportions of their constituent parts, 
and the modes in which they are combined. These objects are at- 
tained by analysis and Spe two general operations, compre- — 
hending the greater number of the processes of chemistry. ee 
_ Analysis is the decomposition of a compound, or the separation of 
its constituent parts. It is effected, either by exposing it to beat, 
hen, from the unequal action of the caloric on the particles of 
which it is composed, they are separated from each other ; or, by 
ubjecting it to the action of a superior attraction, in other words, — 
by presenting it to some substance which exerts an attract one 
or other of its component parts, superior to the attraction 
these were held united. ~ PM A OS eh es 
When the analysis has been effected, we may oftenagain 
the principles obtained, so as to form the compound that has been 
decomposed. This forms what is termed synthesis, which, when it 
can be effected, is always a proof of the accuracy of the analysi 
Very frequently, however, in the decomposition of a compouni 
t.3 
