74 
Not only is the microscope of value in detecting the minute 
crystals of these poisonous agents, but portions “of vegetable 
Fie. 14. 
Crystals of sulphate of atropia, Crystals of daturia, 30 diameters, 
30 diameters. p. 370. 
substances which are taken or administered and act as poisons 
on the system, are detected by its aid. Various poisons are 
used as medicinal agents in the form of powder. Thus 
savine, foxglove, henbane, hemlock, nightshade, tobacco, 
and other plants are used in the form. of powder. These 
may all cause death by being taken or given in large 
quantities. Chemistry in these cases is entirely unavailable 
and useless, but the microscope detects in the intimate 
structure of the various parts of the plants peculiarities by 
which their presence can be positively indicated. Ina large 
number of cases coming before our criminal courts, not only 
is a knowledge of the crystalline structure of vegetable com- 
pounds under the microscope of importance, but also the 
structure of vegetable tissues. Poisons are frequently 
administered in the form of powder, and portions of the 
vomit or contents of the stomach being placed under the 
microscope, will by careful inspection be found to reveal the 
nature of the poison employed. We make no doubt that a 
much larger number of cases of poisoning occur amongst 
children from eating poisonous berries and leaves from gardens 
and waysides than are at present apprehended. In all cases 
where anomalous symptoms set in suddenly with vomiting, 
the vomited matter should be submitted to investigation by 
the microscope. The number of our native wild plants and 
in our gardens that are poisonous are not numerous, and 
every medical practitioner should be made acquainted with 
the structure of their tissues under the microscope. 
Another curious set of cases in which the microscope is of 
