Scientific American Supplement, No. 392, July 7, 1883
V >>
Various >> Scientific American Supplement, No. 392, July 7, 1883
Pages:
1 |
2 |
3 |
4 |
5 |
6 | 7 |
8 |
9 |
10
* * * * *
REDUCTION OF OXIDIZED IRON BY CARBONIC OXIDE.
IT is well known that when the heat is sufficient, carbonic oxide
reduces the oxide of iron to metal with the production of carbon dioxide
(carbonic acid). On the other hand, at lower temperatures carbon dioxide
oxidizes metallic iron, forming carbonic oxide. J. Lowthian Bell's
celebrated researches (see SCIENTIFIC AMERICAN, p. 199, March 31, 1883)
established the point of equilibrium where in the presence of both
monoxide and dioxide the reducing action of the one just counterbalances
the oxidizing action of the other.
At the suggestion of Prof. R. Akermann, of Stockholm, C.G. Saernstrom has
conducted a similar series of forty-five experiments, the expense being
borne by the Jernkontor. About 1 gramme of oxide of iron was placed in a
porcelain boat, and slid in a porcelain tube 18 millimeters (3/4 inch) in
diameter and 635 millimeters long (25 inches). This was exposed to the
action of a current of mixed carbon dioxide and monoxide made by heating
oxalic acid and concentrated sulphuric acid. It was mixed with carbon
dioxide as required, then analyzed, and preserved in gasometers holding
66 liters. Before using, it is passed over phosphorus and chloride of
calcium, and through sulphuric acid. The porcelain tube and boat were
heated to from 300 deg. to 600 deg. C. (572 deg. to 1,652 deg. Fahr.) while the gases
were passing, and then the state of oxidation determined. It was found
that the larger the quantity of dioxide the higher the degree of
oxidation, and the larger the proportion of monoxide the lower the
degree of oxidation.
The details of the experiment indicate that a saving of fuel in the
blast furnace could best be accomplished by the use of a very hot blast,
introducing some carbon monoxide into the blast, provided, of course,
that this gas can be made outside of the blast furnace more cheaply than
inside of it. Nevertheless, 643 lb. of carbon must be burned to
every 1,000 lb. of iron reduced, if carbonic oxide is exclusively
employed.--_Stahl und Eisen_.
* * * * *
ON THE ADULTERATION OF SOAP.
By Dr. H. BRACKEBUSCH.
The importance of soap as an indispensable article in the household has
not restrained the adulterators from making it a favorite object of
their operations, and at the present day soap is only very rarely what
it should be, the alkaline salt of a fatty acid with about 15 per cent.
of water, which may be increased in case of soft soaps to 30 per cent.
at most. The amount of moisture is an immediate signal for adulteration.
Of all substances that can be used to adulterate soap, water is of
course the cheapest, and as it is also harmless, this was the first
point where manufacturers made use of their knowledge. The percentage of
water was raised to 26 or 28 per cent., and now nearly all the ordinary
soaps contain that amount when they leave the factory. At first the
retailers objected to this method, because they had to suffer the loss
so far as it dried out and lost weight in the store.
The next point was to find some substance that would prevent this rapid
drying, and it was very soon discovered that those soaps that contained
an excess of lye retained moisture longer. Henceforth it was only
necessary to use lyes of extra strength so as to obtain a large yield of
soap containing an excess of water. The results of this ingenious method
are before us; in the shops of the soap dealers the bars of soap become
coated with a crust of white crystals, which is nothing but soda. If a
few drops of corrosive sublimate be dropped on these crystals, a red
spot will at once be produced by the formation of mercuric oxide. In
addition to the deception of the public who buy such soaps, this alkali
destroys clothes washed with it, as the fiber of the tissues is directly
attacked by it, while the proper action of the soap depends on its
enveloping the particles of dirt and carrying them off.
Soap is subject to another kind of adulteration called filling, or
weighting. Soapstone and similar mineral substances are added to the
finished soap to increase its weight. But it may be added that this
fraudulent weighting is rare. Large establishments cannot take the risk
of being detected in such avaricious practices, and small ones scarcely
have the apparatus at their disposal for making a uniform mixture which
will not arouse suspicion.
Now soaps are frequently found in the market that scarcely deserve this
name. Mineral soap, cold water soap, etc., are the names inscribed on
the placards behind which is buried a preparation consisting for the
greater part of water-glass. The well-known water-glass is a silicate of
soda or potash dissolved in free or caustic soda, or potash. There was
a time when it excited great hopes, and its introduction into the
household for washing was dreamed of, but it was soon found that
its caustic properties made their appearance at a relatively low
temperature. Hence we often find the notice, "TO BE USED COLD," printed
in bold letters on the wrappers. This product is obtained by thickening
water-glass with stearine, oleine, or any other easily saponifiable fat.
As it takes but very little of the substances named to make an article
closely resembling soap, of course the product is very cheap. There does
not seem to be any limit to the amount of water in it; at least the
author found in one kind of mineral soap from Berlin 58 per cent. of
water. Water-glass soaps do not dissolve readily in water, they make but
little suds, and render the skin hard and unpliable. Admitting that they
are suitable for many purposes, nothing can be said against their sale
so long as they appear under names which preclude their being confounded
with other soaps. Nevertheless, there is always this danger--that
water-glass may come into general use in making soap, and this is to be
deplored. Water-glass soaps are easily recognized by their insolubility
in moderately strong alcohol, the water-glass remaining behind in a
gelatinous form.
Great deception has been practiced under such names as "almond soap,"
etc. Fortunately the difference between various kinds of fat are not
very great from a chemical point of view, although it is always an
unpleasant thought that the fat from animals that have died may return
to the house in the form of soap. A white or yellow soap having a good
smell is not made from bad fat, and hence is more appetizing.
A method formerly much in use consisted in mixing green soap with starch
paste, a mixture that could not be detected by the naked eye, especially
if colored with caramel. On attempting to dissolve it in ordinary
burning alcohol, a white coagulum forms.
From the foregoing it is sufficiently evident that those who buy soap
to sell again have every reason to keep a sharp lookout on those who
furnish them with soap.--_Polyt. Notiz._
* * * * *
BOVINE AND HUMAN MILK: THE DIFFERENCE IN ITS ACTION AND COMPOSITION.
By C. HUSSON.
M. Meynet, in a remarkable report upon condensed milk, has raised a
question which it is important to have solved in the interests of
infants. This is my excuse for presenting to the French Society of
Hygiene certain observations on this subject.
Is woman's milk richer in fatty matters and sugar in proportion to the
caseine than that of the cow? Is the affirmative, sustained by a large
number of chemists, a mistake that ought to be corrected?
Such is the question that needs to be answered.
In my last work on milk, my aim was to report new experiments, and hence
I gave only the analysis of M. Colawell. By the side of the essays of
MM. Doyere, Millon, Commaille, and Wurtz, I put those of Liebig, and
quoted an interesting chapter written on this question by M. Caulier,
in Dechambre's Encyclopedic Dictionary. These are the authorities upon
which to base any opposition to the analyses of Boussingault, Regnault,
Littre, and Simon, savants of no less renown.
The differences are easily explained.
Woman's milk is rarely to be had in sufficient abundance to make a
complete analysis of it. In the country especially a few precious drops,
obtained with difficulty, are carried off in a thimble to be placed
under a microscope, where the number of fat globules are counted, and it
is examined to see if they are not mixed with globules of colostrum.
It will be necessary at the outset to know whether the analyses given
refer to milk drawn from the breast before nursing, or at the end. In
the former case there will be an excess of caseine, in the second an
excess of fat present. This is the reason that in nursing infants the
intervals should not be too long, or the child will not be able to empty
the breast completely, and it will obtain a milk too rich in caseine,
too poor in butter, and one that it cannot digest.
This is the first proof of the importance of fatty matters for the
alimentation of babes.
Let us turn to the second.
At birth, when the milk is still in a state of colostrum, the fluid
contains a variable quantity of albumen coagulable by heat, much less
caseine, and an excess of butter and sugar.
Cow's milk, immediately after calving, contains more butter and less
caseine than milk produced some time later, when the specific character
of ruminants begins to appear in the calf, that is to say, when it
commences to graze the milk coagulates in the stomach. As in other
mammals, an excess of fat helps digestion by subdividing the caseine and
emulsifying it. But the milk of an animal recently calved is reserved
for its young, and it is not until the time of weaning that the lacteal
fluid is offered for human consumption.
Thus it is that the nursling of a day receives milk many months old and
heavily loaded with caseine. This milk it cannot digest because the
emulsifying element, the fat, is not present in it in sufficient
quantity in proportion to the coagulable matter. We must not forget
either that the difference in coagulation holds also with respect to
difference in the age and in the kind of animal. Just so the rennet of a
sucking calf has a greater power of coagulating cow's milk than that of
a sheep, and _vice versa_.
"Clinical observation," says Dr. Condereau, "shows that all young
infants digest human milk very easily and cow's milk very imperfectly.
When it is fed on the latter, in the excreta will be found numerous
fragments, sometimes very bulky, of undigested caseine. In most cases
this caseine suffers more or less decomposition in the alimentary
canal, which gives to the feces a tainted odor recalling that of putrid
Roquefort cheese.
"The excrement vary in appearance as much as they do in odor. Frequently
the caseous clots are not to be seen, and the stool has a clammy look
reminding one of glazier's putty, while the color varies from dirty
white to pale grayish yellow. That is due to the fact that the
composition of the milk from different animals is far from being
constant.
"The proportions of albumen to those of caseine are especially varied.
For woman's milk the proportions are as 100 to 122.72. In goat's milk
the proportions are 100 to 173.09. In cow's milk it is as 100 to 289.20.
"The conclusion is this: Caseine is not a food at all for the new born
during a space of time, the duration of which is to be determined
experimentally.
"This substance is a harmful burden that interferes with the regular
action of the digestive organs. It is a premature food, and the more
abundant the more injurious.
"Albumen on the contrary remains fluid in the presence of the gastric
juice; it is separated from the other aliments by coagulation of the
caseine. It is absorbed entire either in its natural state or in form of
peptone."
According to clinical observation, it is still the fats that give to
milk its hygienic value, and the excess of caseine is an obstacle to its
digestion.
However, if cow's milk is not easily digested by children, experience
proves that there are other kinds of milk, from other animals, which
young stomachs are able to bear more easily. There are many proofs of
this fact.
M. Tarnier, speaking before the Academy of Medicine on the artificial
nourishment of the new born, reports that the milk of cows and goats,
pure or diluted in different ways, that of condensed milk and Biedert's
cream, have always given disastrous results at the Maternite in Paris,
but that the mortality of the new born was considerably reduced from the
day when ass's milk was introduced as food.
Ass's milk was given pure for six weeks or two months; then cow's milk
diluted with one-half water until six months old, followed by pure cow's
milk. This is the most rational course of artificial feeding.
Prof. Parrot reports analogous results obtained at the nursery opened at
the Hospice des Enfants Assistes. By the aid of ass's milk he saved a
number of the little syphilitics.
The following are the numerical results: 86 infants with hereditary
taint of syphilis have been at the nursery. Of 6 fed exclusively on
cow's milk, only 1 survived and the other 5 died. Forty-two were suckled
by goats, of which 8 lived, 34 are dead, which is equal to a mortality
of 80.9 per cent. Thirty-eight were suckled by an ass, of which 28 lived
and 10 died; a mortality of 26.3 per cent.
Certainly these figures prove eloquently enough what chemical analysis
shows, that ass's milk, being better borne by the infant's stomach,
ought to have a composition resembling that of woman's milk. This
analogy is not found to consist in the quantity of fat, but in the small
amounts of dry residue (total solids) and of caseine.
Let us now examine the objections raised by M. Meynet.
Food has a considerable influence upon the composition of milk; this
fact, stated by M. Riche in his treatise on chemistry, seem to be
accepted by all.
The milk of carnivorae is excessively rich in caseine; that of herbivorae
much less.
The food of woman, who enjoys a mixed alimentation, ought to have a
composition intermediate between these two, and consequently ought to
contain more caseine than that of the plant eaters. This is the logical
deduction.
At first this reasoning misleads one, but numerous objections present
themselves.
The food, no doubt, has some influence upon the composition of the milk
of animals of the same species, but every animal can secrete something
independent of any food, just as one kind secretes musk, another
castor, etc. Yet it would not be an anomaly if an excess of caseine
in proportion to the other substances was a true characteristic of
ruminants.
But we admit that the milk of all mammals ought to have identically the
same composition if their food suffered no modifications.
What is the food of ruminants? Without doubt it is essentially
vegetable, and the plants of the field constitute the element par
excellence of their nurture. These plants contain a large excess of
carbohydrates in proportion to the nitrogenous.
But what are these other substances? What role do they play in
digestion?
They are composed in great part of fibers and cells that suffer no
change in the animal economy, and which are not acted upon by the
gastric juice, as proved by their occurrence in excreta. The carbon is
found almost unchanged, so that the excrements of herbivoiae, when dried,
form a valuable fuel. Ruminants are compelled, in order to obtain
nourishment from the plants that they eat, to extract their juices by
repeated pressure (as in chewing the cud); and what do these soluble
juices contain? Some saccharine substances, a little fat, but mostly
albumen and vegetable caseine, that is to say, the substance which
predominates in their lacteal secretions.
What, on the contrary, is the food of woman?
No doubt she gains much strength from the lean, muscular flesh that she
eats, but besides this she has butter, oil, fats of all kinds, sugar,
starches, and alcoholic beverages, all of which are favorable to the
production of butter in the milk. Hence, aside from her physical
constitution, the food of woman alone explains the relative excess of
non-nitrogeneous substances.
Nitrogenous articles of food are expensive, while the other forms of
nutriment are to be had in the form of potatoes, beans, and bread,
products sold at a reasonable price. Yet logic demands that there shall
be an excess of butter in proportion to caseine in the milk.
The discrepancies in analyses of woman's milk are easily explained by
the mobile and impressible character of woman.
If bad treatment and bee stings are able to modify the composition of
cow's milk, how much more ought the emotions of all sorts, which disturb
the heart and head of woman, to change the composition of her milk?
But if new analyses seem to be needed, they ought to be made. This
question is too important to rest in suspense. The mean composition
of human milk for the first two months after delivery ought to be
established. In chemistry, as in mathematics, figures alone are
convincing. But from what has been said it is logical to conclude that
an excess of caseine in milk is unfavorable to good digestion, while
an excess of butter is favorable to it.--_Translated from Journal
d'Hygiene, March 1, 1883_.
* * * * *
CEREAL FOODS IN THEIR RELATION TO HEALTH AND DISEASE.
By F.R. CAMPBELL, A.B., M.D.
The cereals are subject to many diseases which retard their development,
rendering them unfit for food, and even poisonous. The relation of
unwholesome foods to the diseases of the animal body are now being
thoroughly studied, recent advances in chemistry and microscopy
contributing valuable aid to the prosecution of such investigations.
Some enthusiastic advocates of the germ theory of disease believe that
many, if not all, the so-called disease germs may be transplanted into
the human system with the food ingested. But whatever may be the real
truth in regard to this subject, it has been positively demonstrated
that many diseases of the human body may be produced by unwholesome
food. The specific symptoms produced in man by the various grain
diseases are not accurately known, consequently our remarks upon this
subject must be of a very general character.
Pappenheim divides the diseases of the cereals into two classes,
internal and external. The internal diseases are those depending upon
conditions of soil, climate, cultivation, etc., and may be neglected in
our discussion, as they produce no special disease of the body, only
impairing the nutritive value of the grain.
The external diseases are of much greater importance, as they probably
produce some of the most fatal maladies to which the human race is
subject. These external diseases of the cereals are due to parasites,
which may be either of an animal or vegetable nature. Among the animal
parasites may be mentioned the _weevil, vibrio tritici_, which feeds
upon the starch cells of the grain. Grain attacked by this parasite was
at one time supposed to be injurious to health.
In 1844 the French Commission appointed to examine grain condemned a
large quantity imported with this parasite, but afterward reconsidered
their decision and permitted its sale, concluding that it was deficient
in nutritive properties, but not otherwise unwholesome. Rust is the most
common disease of the cereals, produced by vegetable parasites. Like
the other diseases of this class, it is most prevalent in warm, damp
seasons.
Prof. Hensboro is of the opinion that rust is but an earlier stage of
mildew or blight, the one form of parasite being capable of development
into the other, and the fructification characteristic of the two
supposed genera having been evolved on one and the same individual.
Blight is a term loosely applied to a number of parasitic diseases.
In it are included mildew, cories, and even rust and smut. The fungi
producing these diseases attack the plant and seed at various stages of
its growth. The whole kernel is affected, and not merely the external
coat, as is sometimes maintained. When blighted grain is sown, the
disease recurs the following year, often making it necessary to import
new seed before the disease can be eradicated. Various remedies have
been used to destroy the spores of these fungi, but all are uncertain
and some are dangerous to health. Special machinery and methods have
been employed in the mills to separate the mildew from the grain. Some
of these succeed in removing the fungi and discoloration from the
surface of the grain, but have no effects upon the parts within.
Blighted grain is soft, and has an unpleasant taste and smell, and bread
made of it is liable to be heavy and sodden.
It is undeniable that the use of blighted grain as food is exceeding
dangerous to health. It is a well known fact that vegetable parasites
may attack animals; the silk worm disease produced by the _Botrytis
baniana_, being an example. It is stated that the same vegetable
parasites which produce plant diseases, when transmitted to the animal
body produce special affections, the form and appearance of the germs
being altered by their environments. The same germs developed under
different conditions of temperature and surrounding medium, assume forms
so various that they have been supposed to belong to different species
and even different genera. If there is any truth, then, in the germ
theory of disease, it is not so very improbable that a fungus which
will produce blight in grain may cause cholera or tetanoid fever in an
animal.
Hallier, the famous physiological botanist, observed in 1867 that there
was a peculiar disease of the rice plant associated with an epidemic of
cholera. Rice plants fertilized with the discharges of cholera patients
were affected with blight. A concentrated infusion of the blighted grain
would produce changes in all animal substances, blood and albumen being
converted into thin odorless products resembling in every respect the
material found in the kidneys of cholera patients.
The most formidable of the diseases attributed to the use of diseased
grain is cerebro-spinal meningitis, commonly known as spotted or blanoid
fever. The disease is rare in England, but is frequently epidemic in the
United States, in Ireland, and on the Continent. In 1873, in the State
of Massachusetts alone, 747 persons died of it, and other epidemics even
more fatal have lately occurred in New York and Michigan. The disease is
a nervous fever attended with convulsions, the pathological lesion being
congestion and inflammation of the membrane of the spinal cord and
brain. Dr. Richardson in writing on the nature and causes of spotted
fever concludes that it is due to the use of diseased vegetable
substances, especially grain, and from a careful analysis of the
statistics of this disease reported by the Michigan State Board of
Health considers it demonstrated that "under favoring condition for its
action diseased grain received as a food is the primary cause of the
phenomena which characterize the disease." These views are substantiated
by the experiments of Dr. H. Day, who found that by feeding rabbits on
unsound grain, spasmodic affections were produced, due to inflammation
of the membranes of the spinal cord and brain.
In warm climates, pellagra or Italian leprosy is said to be produced by
eating diseased maize, which forms the principal article of food among
the poorer classes of the rural districts. Pellagra is epidemic in
northern Italy and the south of France. The disease is manifested by a
redness and discoloration of the exposed parts of the body. It is most
active during the hot weather, the inflammation subsiding in the winter,
leaving a pigmentation of the skin. Each year the symptoms become more
alarming, nervous disorders finally setting in, and a large number die
insane. The disease is most prevalent in the country. In the towns,
where maize is supplemented by other articles of food, it does not
exist.
Ergot is a very common disease of the cereals. The fungus producing it
was discovered in 1853, but for centuries previous its injurious effects
upon the human body were recognized, and it was observed that ergot of
rye was the most poisonous. Taken in large doses, ergot will produce
nausea, vomiting, diarrhoea, headache, and weakness of the heart. In
small repeated doses it will produce contraction of all the unstriped
muscles, as those of the blood vessels, the womb, and intestines.
Ergotium is the name given to the disease produced by the continued use
of grain affected by this fungus. Aitken describes it as "a train of
morbid symptoms produced by the slow and cumulative action of a specific
poison peculiar to wheat and rye, which produces convulsions, gangrene
of the extremities, and death. In countries where rye bread is much used
ergotium is sometimes epidemic. This was a frequent calamity before
the introduction of suitable purifiers into the mills. There are two
varieties of the disease, the convulsive and the gangrenous. The
convulsive form begins with tingling of the extremities, drowsiness, and
headache, followed by pain in the joints, violent muscular contractions,
and death. The gangrenous variety begins with coldness and weakness
of the extremities followed by gangrene and sloughing. This form is
somewhat more fatal than the convulsive, the mortality of those affected
being about 90 per cent.
Pages:
1 |
2 |
3 |
4 |
5 |
6 | 7 |
8 |
9 |
10