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16
REPORT OF THE MEDICAL OFFICER OF HEALTH
family from living in a single room; but they might, by insisting that no corpse
shall be kept in an occupied dwelling-room, and erecting a small mausoleum, in
which the dead might be safely deposited until the time for their burial might
arrive.
Such a building in Clerkenwell might be erected above the large vault,
between Ray-street and Victoria-street.
FOOD.
It is well known that most of the articles of food supplied by the shops are
adulterated, i.e. they are mixed with substances not implied to exist in them
under the name by which they are sold. The question of adulteration has
two bearings, viz.:—the articles substituted may be less expensive than the
pure substances, whereby a fraud is committed upon the purchaser, and as
most of the articles are liable to duty, the revenue is defrauded also; or the
articles substituted may be noxious, and injurious to the health of the consumer.
With the first bearing of the question I have no concern; this
belongs to the Excise; and the latter will not occupy me long, for its importance
has been greatly exaggerated. I have examined numerous samples of
the different articles supplied by the shopkeepers of the district, and will
comment briefly upon the results obtained in regard to the principal substances.
BREAD.
I need not state that alum has been added to the flour and bread in this, as
in other districts of the Metropolis. The effects of this admixture upon the
health have often been discussed; and it has been argued very naturally that
because alum has been added to bread, the injurious action of that salt will be
exerted upon the body. But the subject has been very imperfectly handled,
and I cannot admit the truth of this view.
When alum is mixed with flour, and the mass is wetted, the salt is decomposed,
and its earthy base is rendered insoluble and totally inactive—the alum
exists no more. This decomposition is produced partly by the action of the
nitrogenous compounds (gluten, albumen, &c.) upon the alum, but principally
by the soluble phosphates existing naturally in the flour, in quantity
much larger than is sufficient to decompose the alum used.
It is the white precipitate formed in this decomposition which gives the
superior whiteness to bread made from flour of whatever quality.*
*The mistakes which have been made in regard to the presence and detection of
alum in bread, by those who have undertaken to enlighten us upon this matter, are
remarkable. None of the published processes for the detection of alum are of any
value; and all the quantitative results have been obtained by precipitating the
naturally existing phosphate of magnesia from the watery extract of bread by
ammonia, and calculating the amount of alum from this, reckoned as alumina! That
alum has been used in making any sample of bread may be readily discovered.
If a piece of pure bread be kept in a cold decoction of logwood for about eight hours,
it will become dyed of a reddish purple or reddish brown colour; whilst, if the
bread be alumed, it will assume a bluish purple, or violet colour. When solution of
alum is added to the decoction of logwood, the solution, which is yellowish red,
becomes reddish purple, not bluish purple or violet. But if we add phosphate of
alumina, which I have stated to be formed by the action of the soluble phosphate
existing in the bread upon the alum, the solution and the precipitate become bluish
purple or violet; hence showing that the phosphate of alumina is really formed as
stated.