422 POISONS : THEIR EFFECTS AND DETECTION. [§§ 505 - 507 . 
effects of the former, and in the greater influence on the heart of the 
latter. ♦ 
§ 505. Post-mortem Appearances. —But little is known relative to 
the post-mortem appearances likely to be found in human poisoning ; 
redness of the stomach and intestines is probably the chief sign. 
§ 506. Separation of Physostigmine. —For the extraction of physo- 
stigmine from the fluids of the body, Dragendorff recommends benzene : 
the alcoholic filtered extract (first acidified) may be agitated with such 
solvents as petroleum and benzene, in order to remove colouring-matter ; 
then alkalised and shaken up with benzene, and the latter allowed to 
evaporate spontaneously—all the operations being, as before stated, 
carried on under 40°. If much coloured, it may be purified according 
to the principles before mentioned. In cases where enough of the 
extract (or other medicinal preparation) has been taken to destroy life, 
the analyst, with proper care, would probably not have much difficulty 
in separating a small quantity of the active principle. It is rapidly 
eliminated by the saliva and other secretions. In most cases it will be 
necessary to identify physostigmine by its physiological activity, as well 
as by its chemical characters. For this purpose a small quantity of the 
substance should be inserted in the eye of a rabbit; if it contains the 
alkaloid in question, in twenty minutes, at the very latest, there will 
be a strong contraction of the pupil, and a congested state of the con¬ 
junctival vessels. Further researches may be made with a small 
quantity on a bird or frog. The chief symptoms observed will be those 
of paralysis of the respiratory and voluntary muscles, followed by death. 
If a solution is applied to the web of a frog’s foot, the blood-vessels 
become dilated. Physostigmine appears, according to Dragendorff and 
Pander, to act as an irritant, for they always observed gastro-enteritis 
as a result of the poison, even when injected subcutaneously. The 
enhanced secretion from all mucous surfaces, and the enlargement of 
the blood-vessels, are also very constant symptoms. But of all these 
characteristics, the contraction of the pupil is, for the purposes of 
identification, the principal. A substance 'extracted from the tissue or 
other organic matters, in the manner mentioned, strongly contracting 
the pupil and responding to the tests enumerated, would, in the 
present state of our knowledge, be indicative of physostigmine, and 
of that alone. 
§ 507. Fatal Dose of Physostigmine. —One mgrm. (-015 grain) as 
sulphate, given by Yee to a woman subcutaneously, caused vomiting, etc., 
after half an hour. A disciple of Gubler’s took 2 mgrms. without 
apparent effect ; but another mgrm., a little time after, caused great 
contraction of the pupil and very serious symptoms, which entirely 
passed off in four hours. It would thus seem that three times this ( i.e . 
6 mgrms.) would be likely to be dangerous. Hence man is far more 
