_Weaker or Proof Spirit._
This is rectified spirit diluted with a certain proportion of water, and
it is to be regretted that the quantity ordered for this purpose, should
vary in the different Pharmacopœias; thus, according to the London and
Dublin Colleges, its specific gravity is ·930, while the College of
Edinburgh directs it to be of ·935. The former consists of 44 per cent.
of pure alcohol, and may be formed by mixing _four_ parts, by measure,
of rectified spirit, with _three_ of water; the latter contains only 42
_per cent._ of pure alcohol, and may be made by adding together _equal
parts_ of rectified spirit and distilled water. Alcohol in this state of
dilution, is better adapted for taking up the principles of vegetables
than rectified spirit; indeed, diluted alcohol acts upon bodies as a
chemical compound, and will dissolve what neither the same proportion of
water nor of alcohol would, if separately applied; we perceive therefore
the importance of ensuring uniformity of strength in our spirits. (See
_Tincturæ_.) It is necessary to remark that almost all the spirit sold
under the name of “_Proof Spirit_,” is contaminated with empyreumatic
oil, and is unfit for the purposes of pharmacy; it ought therefore to be
extemporaneously prepared by mixing together rectified spirit and water,
in the proportions above stated. This however is rarely done, except the
liquors are intended for the toilet, and hence it has been observed,
that the cordials of the apothecary are generally less grateful than
those of the distiller, the latter being extremely curious in rectifying
and purifying his spirit. If common water be employed for the dilution
of alcohol, the resulting spirit will be turbid, owing principally to
the precipitation of sulphuric salts; this circumstance lately
occasioned considerable embarrassment to the Curators of the Hunterian
Museum at the College of Surgeons, who were compelled to prepare their
own spirit, in consequence of an excise regulation preventing the
distiller from sending out any spirit of that strength which is required
for their anatomical purposes. A curious fact has just been noticed in
the Laboratory of the Royal Institution, which is, that diluted spirit
_becomes stronger_ by being kept in vessels that are carefully closed by
bladder! whence it would seem, that alcoholic vapour transpires through
this animal membrane less freely than aqueous vapour; we are at present
unable to offer a satisfactory explanation of this anomalous case of
distillation, but it is probably connected with the different solvent
powers of these two liquids, in relation to the animal membrane. MED.
USES. Alcohol, although diluted to the degree of proof spirit, is still
too strong for internal exhibition; indeed, where its use is indicated,
it is more generally given in the form of wine, malt liquors, or ardent
spirits, which must be regarded only as diluted alcohol, although each
has a peculiarity of operation, owing to the modifying influence of the
other elements of the liquid; thus _Brandy_[647] is said to be simply
cordial and stomachic;[648] _Rum_,[649] heating and sudorific; _Gin_ and
_Whiskey_, diuretic; and _Arrack_,[650] styptic, heating, and narcotic;
it seems also probable that a modified effect is produced by the
addition of various other substances, such as sugar and acids, which
latter bodies, besides their anti-narcotic powers, appear to act by
favouring a more perfect combination and mutual penetration of the
particles of spirit and water. Foreign brandy derives its colour from
the oak cask, the intensity of which, therefore, affords some criterion
of its age. The English have been in the habit of colouring their
spirits with burnt sugar until lately, but now since the cause of the
foreign colour is discovered, the scrapings of gall-nuts are employed
for that purpose, whence the sulphate of iron is no longer a test of
brandy being genuine.[651] The effects, also, which are produced by the
habitual use of fermented liquors, differ essentially according to the
kind that is drunk; thus Ale and Porter, in consequence of the nutritive
matter, and perhaps the invigorating bitter with which they are charged,
and the comparatively small proportion of alcohol which they contain,
dispose to a plethora, which is not unfrequently terminated by apoplexy;
Spirits, on the other hand, induce severe dyspepsia, obstructed and
hardened liver, dropsy, and more than half of all our chronical
diseases; and Dr. Darwin moreover remarks that when they arise from this
cause, they are liable to become hereditary, even to the third
generation, gradually increasing, if the cause be continued, till the
family become extinct; with regard to Wine, Rush has truly observed that
its effects, like those of tyranny in a well formed government, are
first felt in the extremities, while spirits like a bold invader, seize
at once upon the vitals of the constitution; the different kinds of
wine, however, produce very different and even opposite effects, as
stated under the history of that article, (see _Vinum_.) The excise
officers frequently avail themselves of the peculiar power of the
sub-acetate of lead to precipitate colouring matter, in order to remove
from seized Holland Gin, the colour which it contains by being long kept
in the tubs in which it is smuggled over. This practice, however,
renders the gin liable to gripe.