On the Preservation of jVediclnes. 
271 
moisture, no organic change can occur. The apothecaries' 
care should be to prevent the access of this, as much to avoid 
its primary effects, which are mouldiness, or other elementary 
modifications, as to prevent its secondary influence, which is 
the developement of a number of destructive insects, precur- 
sors, even more ominous of decomposition, than mouldiness 
itself. 
Thus entire plants, or their parts separately from the root 
to the seed, ought to be very dry, shut up in impermeable 
vessels, screened as much as possible from the contact of 
light, and of a capacity proportioned to the quantity of mat- 
ter. In my own establishment I always make use of boxes 
and bottles of such a capacity as to be emptied in a short 
time. 
The preservation of roots, woods, leaves, flowers and fruits 
in general, require no other attention than that of putting these 
substances, very dry in vessels shutting as exact as possible, 
and least accessible to moisture. However, the necessity of 
opening them often ; variation of temperature ; atmospheric 
pressure acting in the interior of the vessel, the renewal of 
the air, and this air incessantly charged with moisture, which 
moisture by hygrometical affinity for organic matters, com- 
bines with and completely saturates them, all act in an inju- 
rious manner. Thence, the necessity of putting the same sub- 
stance in contact with heat several times in the course of the 
year, and of enclosing it when perfectly dry in the same ves- 
sel previously well cleaned, and thoroughly dried. Without 
these precautions, the moisture extricated in vapour during the 
warm season of the year, not being able to escape, owing to 
the resistance of the sides of the vessel, falls down again upon 
the substance, and occasions a sudden alteration in it. 
Change of colour, mouldiness, and increase of insects are 
never more frequent in substances, shut up in close vessels, 
than at the commencement of spring and during the course 
of the summer. This is why I have always used the precau- 
tion, at the end of March, of subjecting such substances as 
remained on hand during the winter to the action of heat in 
