246 
INTRODUCTORY LECTURE. 
This department is especially useful in the choice of drugs, 
and is the ground-work of a good stock, without which, it is 
hardly necessary to observe, all subsequent nicety in pharma- 
ceutical treatment will be labour lost. The natural causes of 
imperfection, arising from growing plants inungenial climates, 
and their unseasonable collection ; together with the deteriora- 
ting influences of age, light, moisture, etc., are duly explained 
and remedies suggested for defending and preserving them, so 
necessary to the druggist. And finally, it points out the adul- 
terations and falsifications that drugs are liable to from the cu- 
pidity of collectors and dealers, (a species of rascality that is 
abundantly practised at this time,) and indicates the means of 
their recognition and detection. 
The second division comprehends the study of the chemical 
and physical laws bearing on pharmacy. It is here that the 
most difficulties occur to the student. He has to master the 
general principles of Chemistry, and such of the physical laws 
as are embraced in the subjects of heat, light, electricity, and 
the structure and divisibility of matter. The principles of me- 
chanics, hydraulics and hydrostatics, are exceedingly useful in 
the construction of apparatus or its adaptation to processes, 
and should be studied with a view to these objects. General 
Chemistry includes the history of mineral or inorganic drugs, 
their mineralogical derivation, properties, etc. 
The third department consists in the application of the 
aforesaid laws to the modification of drugs — in a word, it is 
'practical pharmacy, and constitutes the mass of the every-day 
business of the shop and laboratory. 
The ground work of practical pharmacy is expert manipula- 
tion ; hence the first object in this department is an acquaint- 
ance with the elementary operations required by the apothe- 
cary. These comprehend the processes and instruments used 
in effecting the mechanical division of drugs ; the separation 
of solids from fluids ; the solution of solids in liquids ; the ex- 
traction of the soluble from the insoluble ingredients of a com- 
pound ; the evaporation of fluids and the recovery of solids 
