rvals, especially when the final
doses of record were to be taken.

The next agent tried in precisely this same way was coca; and knowing
that the quality of that which was attainable was very low, the
commencing dose of the leaf in substance was 2 drachms, or about 8
grammes. This gave no very definite effect, but 21/2 drachms did give a
definite effect, and a subsequent dose of 21/2 fluid drachms of a well made
fluid extract of coca gave about the same effect as 21/2 grains of
caffeine. Three fluid drachms of the fluid extract were about equivalent
to 3 grains of caffeine.

Both the coca used and the fluid extract were then assayed by the modern
methods, for the proportion of the alkaloid they contained.

The only assays of coca that could be found conveniently were those of
Dr. Albert Niemann, of Goslar, given in the _American Journal of
Pharmacy_, vol. xxxiii., p. 222, who obtained 0.25 per cent.; and of
Prof. Jno. M. Maisch, in the same volume of the same journal, p. 496, who
obtained 4 grains of alkaloid from 1,500 grains of coca, which is also
about a quarter of one per cent. These assays were, however, very old,
and made by the old process. The process used by the writer was the more
modern one of Dragendorff slightly modified. It was as follows:

Thirty grammes of powdered coca, thoroughly mixed in a mortar with 8
grammes of caustic magnesia, were stirred into 200 c.c. of boiling water,
and the mixture boiled for ten minutes. The liquid was filtered off, and
the residue percolated with about 60 c.c. of water. It was then again
stirred into 150 c.c. of boiling water, and was again boiled and
percolated until apparently thoroughly exhausted. The total liquid,
amounting to more than 600 c.c., was evaporated on a water-bath,
commencing with the weaker portions, so that the stronger ones might be
exposed to the heat for the shortest time, until reduced to about 20 c.c.
This liquid extract was transferred to a flask, and vigorously shaken
with 50 c.c. of strong ether. The ether was poured off, as closely as
practicable, into a tared capsule, where it was allowed to evaporate
spontaneously. A second and third portion of ether, each of 50 c.c., were
used in the same way, and the whole evaporated to dryness in the capsule.
A scanty, greenish, oily residue was left in the capsule, in which there
was no appearance of a crystallized alkaloid. The capsule and contents
were then weighed and the weight noted. The oily resi