; “PART I. rate | 
PHARMACEUTIC CHEMISTRY. > 
‘a view to their eatiendl properties, and petty fine oe 
operations by which they are fitted to act with more efficacy or safety 
as remedies against disease. It includes those facts and principles 
which connect materia medica and pharmacy, the enuineration of 
which forms the proper introduction to the study of these two bran- 
_ ches of medicine. 
SECTION IL. | 
PHARMACEUTICAL OPERA 
THE phenomena which it is the object of chemistry to investigate, 
and upon which, therefore, the principal operations of pharmacy de- 
pend, arise principally from the exertion of that power i by 
of different kinds of matter, by which they have a ten- 
dency to combine together. When two different bodies are placed 
in contact, under certain circumstances, they unite, and form one 
homogeneous substance, in which the particles of either can no 
longer he discovered. The power whence this combination proceeds, 
is termed chemical attraction or affinity. Itis exerted only between 
the minute particles of different kinds of matter, and between = | 
these only at insensible distances. The substances which. ee ee 
bines never-separate spontancously, nor.are they capable. of being — 
separated by any mechanical means; and they forma 
oe properties more or less different from those of its compo- 
The change of properties from combination is the most remarkable 
the exertion of chemical attraction. The 
cuiicane qualities, and.chemical properties of the compound, bear in 
general no resemblance to these qualities and properties in the sub- 
stances of which itis formed. This, however, is not invariably true. 
There are a number of instances, especially i in pharmacy, where the _ 
change is much less complete, as in the solutions of resins or essen- — 
tial oils.in alcohol,.or of gums or saline substances in water. But 
‘these the marks of chemical cémbination are still present, the « 
is is homogeneous, and cannot be Poot! but by, 
