68 
methods of examination are based upon the determinations of 
such percentages, by the extraction of the constituents in ques- 
tion and their subsequent identification. 
In many cases an adulterant may be added in such small 
amount that it will not reduce the percentage of active constituent 
below the standard. In other cases, as to drugs, the active con- 
stituent is not known, or is not amenable to chemical determina- 
tion, and for these and other reasons, the detection of adulterants 
by chemical methods is often impracticable, or even impossible. 
In many such cases, detection is possible by physical methods. 
In the lecturer's opinion, the number of cases in which physical 
methods could determine quality while chemical methods could 
not, was much greater than the number of those in which the 
conditions were reversed. Hence, the great importance of 
microscopical analysis, a method that is yet in its infancy. 
The method of physical examination most generally useful is 
that of ordinary examination, by sight, touch, smell, fracture, 
etc., on the part of an experienced examiner, perfectly familiar 
with the articles, but very often, especially in the case of finely 
powdered substances, these methods would wholly fail. Then 
recourse must be had to the compound microscope. The anatom- 
ical elements of vegetable substances, however minute, are in 
most cases quite as distinctly characteristic as are the entire 
plant bodies to which they pertain, and all that is necessary is to 
magnify their appearance by the aid of the compound microscope. 
Numerous lantern slide illustrations were employed to show 
the distinctive elements in various drugs and their principal 
adulterants, these pertaining to trichomes, epidermis, fibers, 
stone-cells, crystals, and starch-grains. 
Meeting adjourned. 
В. О. DopGE, 
Secretary 
JANUARY 9, 1912 
The first meeting of the Club for 1912 was held at the American 
Museum of Natural History at 8:15 p.m. Vice-President 
presided. Twenty-two persons were present. 
