420 poisons: their effects and DETECTION. [§§5 02 >5°3- 
a broader but more nebulous band in the blue and violet between A 400 
and A 418, and a very feeble band in the orange. 
J. B. Nagelvoort 1 has recommended the following tests :—( a ) An 
amorphous residue of a permanent blue colour is obtained if a trace of 
the alkaloid, or one of its salts, is evaporated in the presence of an excess 
of ammonia ; this blue alkaloid dissolves in dilute acids with a red colour ; 
sensitiveness O'OOOOl grm. (1 : 100000). The solution has beautiful red 
fluorescence in reflected light ; when evaporated, it leaves a residue that 
is green at first, changing to blue afterwards, the blue residue being 
soluble in water, alcohol, and chloroform, but not in ether. Chloroform 
extracts the blue colour from the watery ammoniacal solution only par¬ 
tially. The blue solutions are reddened at first by H 2 S, and discoloured 
afterwards. The blue colour is restored by expelling the H 2 S on the 
water-bath. ( b ) Eserine and its salts, dissolved in fuming nitric acid, 
give a yellow solution which, when warmed on the water-bath, becomes 
darker and leaves a green residue. The latter dissolves with a green 
colour in water and alcohol; in dilute nitric acid the solution shows 
a greenish-yellow fluorescence by transmitted light, and a blood-red by 
reflected light. ( c ) A red fluid is obtained when 0-010 grm. eserine or 
its salicylate, 0-050 grm. of slaked lime, and 1 c.c. of water are mixed 
together. Warmed in a water-bath, it turns green, and a piece of red 
litmus-paper suspended in the test tube turns blue; a glass rod 
moistened with HC1 gives off the well-known white clouds character¬ 
istic of an ammonia reaction. The green solution does not lose its 
colour by evaporation. Baryta water, added to an eserine solution, gives 
a white precipitate that turns red when strongly agitated, sensitive to 
0 01 mgrm. (1 : 100000). 
§ 502. Pharmaceutical Preparations. —The only preparations official 
in this country are a spirituous extract ( extractum physostigmatis), used 
principally for external application, the dose of which is not more than 
18-1 mgrms. (-28 grain), and gelatine discs for the purpose of the ophthal¬ 
mic surgeon, each disc weighing about grain, and containing 
toVo g r - the alkaloid. 
§ 503. Effects on Animals. —A large number of experiments have 
been made upon animals with physostigmine, most of them with the 
impure alkaloid, which is a mixture of calabarine and physostigmine. 
Now, the action of calabarine seems to be the opposite to that of physo¬ 
stigmine—that is, it causes tetanus. Hence, these experiments are not 
of much value, unless the different proportions of the alkaloids are 
known. Harnack and Witkowsky 2 made, however, some researches 
with pure physostigmine, of which the following are the main results :— 
The smallest fatal dose for rabbits is 3 mgrms. per kilo. ; cats about the 
same ; while dogs take from 4 to 5 mgrms. per kilo. Frogs, under the 
1 Fllickiger’s Reactions, 1893. 2 Arch. f. Pathol, u. Pharm., 1876, Bd. v. 
