winter and spring when the weather is mild, but there is snow, or the
ground is damp, more clothes are necessary than when it is freezing hard
and the air is dry.

* * * * *

PREPARATION OF MEDICINE.

As it often becomes necessary for the practitioner to make more or less
of his own dilutions and attenuations, some brief instructions
especially to new beginners, may not come amiss.

Medicine is prepared by mixing it with distilled water, or purified 98
per cent. Alcohol; or if solid and dry, by reducing it to powder and
triturating (rubbing) it in a mortar with pure sugar or Sugar of Milk.
The liquid is called _dilution_, the powder _trituration_. The
attenuations are mostly made at the decimal (1-10,) or centecimal
(1-100) ratio and numbered 1, 2, 3, &c., by putting ten drops of the
liquid with ninety drops of Alcohol, or ten grains of the powder with
ninety grains of Sugar for the 1st, and ten grains or drops of the 1st
with ninety more of Alcohol or Sugar, as the case may be, for the 2nd,
and so on to any desirable extent.

If the centecimal attenuation is adopted, one grain or drop is used
instead of ten, as in the decimal.

I prefer the decimal to the centecimal ratio. Not that there can
possibly be any difference in the action of the medicines, at the same
attenuation, whether it was brought to that state through a series of
1-10, or 1-100; the 3d at the 1-100 ratio of dilution being _precisely
the same_ as the 6th at 1-10. My preference for the decimal ratio is
based upon the greater convenience and accuracy of measuring larger
quantities.

_Accuracy_ is very desirable, but the practice of _guessing_ at the
amount as pursued by some, is anything but accurate. When one makes his
dilutions by putting the fluid into a vial and "_pouring it all out_,"
_guessing_ that he has a _drop_ left which is to medicate the
ninety-nine drops of Alcohol or water, he may put in by guess, I am
inclined to _guess_ that he knows nothing, _accurately_ as to what
dilution he is making. (See Hull's Laura, introduction, also Jahr &
Possart's Pharmacopoeia and Posology.) For if the vial is small and
quite smooth there may not be a drop left, or if it is rough, there may
be several drops.

Yet some physicians make their dilutions thus, and insist upon the
superiority of the centecimal over the decimal attenuations.

Whatever ratio is adopted, should be _accurately_ followed. Have true
scales for