Scientific American Supplement No. 275 by Various
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Various >> Scientific American Supplement No. 275
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SCIENTIFIC AMERICAN SUPPLEMENT NO. 275
NEW YORK, APRIL 9, 1881
Scientific American Supplement. Vol. XI, No. 275.
Scientific American established 1845
Scientific American Supplement, $5 a year.
Scientific American and Supplement, $7 a year.
* * * * *
TABLE OF CONTENTS.
I. ENGINEERING AND MECHANICS.--The Various Modes of
Transmitting Power to a Distance. (Continued from No. 274.)
By ARTHUR ARCHARD. of Geneva.--II. Compressed Air.--III.
Transmission by Pressure Water.--IV. Transmission by
Electricity.--General Results
The Hotchkiss Revolving Gun
Floating Pontoon Dock. 2 figures.--Improved floating pontoon dock
II. TECHNOLOGY AND CHEMISTRY.--Wheat and Wheat Bread. By H. MEGE
MOURIES.--Color in bread.--Anatomical structure and chemical
composition of wheat.--Embryo and coating of the embryo.--
Cerealine--Phosphate of calcium.--1 figure, section of a grain
of wheat, magnified.
Origin of New Process Milling.--Special report to the Census
Bureau. By ALBERT HOPPIN.--Present status of milling structures
and machinery in Minneapolis by Special Census Agent C. W.
JOHNSON.--Communication from GEORGE T. SMITH.
Tap for Effervescing Liquids. 1 figure.
London Chemical Society.--Notes.--Pentathionic acid, Mr.
VIVIAN LEWES.--Hydrocarbons from Rosin Spirit. Dr.
ARMSTRONG.--On the Determination of the Relative Weight of Single
Molecules. E. VOGEL.--On the Synthetical Production of Ammonia
by the Combination of Hydrogen and Nitrogen in the Presence of
Heated Spongy Platinum, G. S. JOHNSON.--On the Oxidation of
Organic Matter in Water, A. DOWNS.
Rose Oil, or Otto of Roses. By CHAS. G. WARNFORD LOCK.--Sources
of rose oil.--History--Where rose gardens are now cultivated
for oil.--Methods of cultivation.--Processes of
distillation.--Adulterations
A New Method of Preparing Metatoluidine. By OSCAR WIDMAN.
III. AGRICULTURE, HORTICULTURE, ETC.--The Guenon Milk Mirror. 1 figure.
Escutcheon of the Jersey Bull Calf, Grand Mirror.
Two Good Lawn Trees
Cutting Sods for Lawns
Horticultural Notes: New apples, pears, grapes, etc.--Discussion
on Grapes. Western New York Society.--New peaches.--Insects
affecting horticulture.--Insect destroyers.
Observations on the Salmon of the Pacific. By DAVID S. JORDAN
and CHARLES B. GILBERT. Valuable census report.
IV. LIGHT, ELECTRICITY ETC.--Relation between Electricity
and Light. Dr. O. T. Lodge's lecture before the London Institute.
Interesting Electrical Researches by Dr. Warren de La Rue and
Dr. Hugo Miller.
Telephony by Thermic Currents
The Telectroscope. By Moxs. SENLECQ. 5 figures. A successful
apparatus for transmitting and reproducing camera pictures by
electricity.
V. HYGIENE, MEDICINE, ETC.--Rapid Breathing as a Pain Obtunde in
Minor Surgery, Obstetrics, the General Practice of Medicine, and
of Dentistry. Dr. W. G. A. Bonwill's paper before the
Philadelphia County Medical Society. 8 figures. Sphygmographic
tracings.
VI. ARCHITECTURE, ART, ETC.--Artist's Homes. No. 11. "Weirleigh."
Residence of Harrison Weir. Perspective and plans.
* * * * *
WHEAT AND WHEAT BREAD.
By H. MÈGE-MOURIÈS.
In consequence of the interest that has been recently excited on the
subject of bread reform, we have, says the London _Miller_, translated the
interesting contribution of H. Mège-Mouriès to the Imperial and Central
Society of Agriculture of France, and subsequently published in a separate
form in 1860, on "Wheat and Wheat Bread," with the illustration prepared
by the author for the contribution. The author says: "I repeat in this
pamphlet the principal facts put forth in the notes issued by me, and in
the reports furnished by Mr. Chevreul to the Academy of Science, from 1853
up to 1860."
The study of the structure of the wheat berry, its chemical composition,
its alimentary value, its preservation, etc., is not alone of interest to
science, agriculture, and industry, but it is worthy of attracting the
attention of governments, for this study, in its connection to political
economy, is bound up with the fate and the prosperity of nations. Wheat has
been cultivated from time immemorial. At first it was roughly crushed and
consumed in the form of a thick soup, or in cakes baked on an ordinary
hearth. Many centuries before the Christian era the Egyptians were
acquainted with the means of making fermented or leavened bread; afterwards
this practice spread into Greece, and it is found in esteem at Rome two
centuries B.C.; from Rome the new method was introduced among the Gauls,
and it is found to-day to exist almost the same as it was practiced at that
period, with the exception, of course, of the considerable improvements
introduced in the baking and grinding.
Since the fortunate idea was formed of transforming the wheat into bread,
this grain has always produced white bread, and dark or brown bread, from
which the conclusion was drawn that it must necessarily make white bread
and brown bread; on the other hand, the flours, mixed with bran, made a
brownish, doughy, and badly risen bread, and it was therefore concluded
that the bran, by its color, produced this inferior bread. From this error,
accepted as a truth, the most contradictory opinions of the most opposite
processes have arisen, which are repeated at the present day in the art of
separating as completely as possible all the tissues of the wheat, and of
extracting from the grain only 70 per cent of flour fit for making white
bread. It is, however, difficult for the observer to admit that a small
quantity of the thin yellow envelope can, by a simple mingling with the
crumb of the loaf, color it brown, and it is still more difficult to admit
that the actual presence of these envelopes can without decomposition
render bread doughy, badly raised, sticky, and incapable of swelling in
water. On the other hand, although some distinguished chemists deny or
exalt the nutritive properties of bran, agriculturists, taking practical
observation as proof, attribute to that portion of the grain a
physiological action which has nothing in common with plastic alimentation,
and prove that animals weakened by a too long usage of dry fodder, are
restored to health by the use of bran, which only seems to act by its
presence, since the greater portion of it, as already demonstrated by Mr.
Poggiale, is passed through with the excrement.
With these opinions, apparently so opposed, it evidently results that there
is an unknown factor at the bottom of the question; it is the nature of
this factor I wish to find out, and it was after the discovery that I
was able to explain the nature of brown bread, and its _role_ in the
alimentation of animals. We have then to examine the causes of the
production of brown bread, to state why white bread kills animals fed
exclusively on it, while bread mixed with bran makes them live. We have to
explain the phenomena of panification, the operations of grinding, and to
explain the means of preparing a bread more economical and more favorable
to health. To explain this question clearly and briefly we must first be
acquainted with the various substances forming the berry, their nature,
their position, and their properties. This we shall do with the aid of the
illustration given.
[Illustration: SECTION OF A GRAIN OF WHEAT MAGNIFIED.]
EXPLANATION OF DIAGRAM.
1.--Superficial Coating of the Epidermis, severed at the Crease of
the Kernel.
2.--Section of Epidermis, Averages of the Weight of the Whole Grain, ½ %.
3.--Epicarp, do. do. do. 1 %.
4.--Endocarp, do. do. do. 1 ½ %.
5.--Testa or Episperm, do. do. do. 2 %.
6.--Embryo Membrane (with imaginary spaces in white on both sides
to make it distinct).
7.\ / Glutonous Cells \
8. > Endosperm < containing > do. do. 90 %.
9./ \ Farinaccous Matter /
ANATOMICAL STRUCTURE AND CHEMICAL COMPOSITION OF WHEAT.
The figure represents the longitudinal cut of a grain of wheat; it was made
by taking, with the aid of the microscope and of photography, the drawing
of a large quantity of fragments, which, joined together at last, produced
the figure of the entire cut. These multiplied results were necessary to
appreciate the insertion of the teguments and their nature in every part
of the berry; in this long and difficult work I have been aided by the
co-operation of Mr. Bertsch, who, as is known, has discovered a means of
fixing rapidly by photography any image from the microscope. I must state,
in the first place, that even in 1837 Mr. Payen studied and published the
structure and the composition of a fragment of a grain of wheat; that
this learned chemist, whose authority in such matters is known, perfectly
described the envelopes or coverings, and indicated the presence of various
immediate principles (especially of azote, fatty and mineral substances
which fill up the range of contiguous cells between them and the periphery
of the perisperm, to the exclusion of the gluten and the starchy granules),
as well as to the mode of insertion of the granules of starch in the gluten
contained in the cells, with narrow divisions from the perisperm, and in
such a manner that up to the point of working indicated by the figure 1
this study was complete. However, I have been obliged to recommence it, to
study the special facts bearing on the alimentary question, and I must say
that all the results obtained by Mr. Bertsch, Mr. Trécul, and myself agree
with those given by Mr. Payen.
ENVELOPES OF THE BERRY.
No. 1 represents a superficial side of the crease.
No. 2 indicates the epidermis or cuticle. This covering is extremely light,
and offers nothing remarkable; 100 lb. of wheat contain ½ lb. of it.
No. 3 indicates the epicarp. This envelope is distinguished by a double
row of long and pointed vessels; it is, like the first one, very light and
without action; 100 lb. of wheat contain 1 lb. of it.
No. 4 represents the endocarp, or last tegument of the berry; the
sarcocarp, which should be found between the numbers 2 and 3, no longer
exists, having been absorbed. The endocarp is remarkable by its row of
round and regular cells, which appear in the cut like a continuous string
of beads; 100 lb. of wheat contain 1½ lb. of it.
These three envelopes are colorless, light, and spongy; their elementary
composition is that of straw; they are easily removed besides with the aid
of damp and friction. This property has given rise to an operation called
decortication, the results of which we shall examine later on from an
industrial point of view. The whole of the envelopes of the berry of wheat
amount to 3 lb. in 100 lb. of wheat.
ENVELOPES AND TISSUES OF THE BERRY PROPER.
No. 5 indicates the testa or episperm. This external tegument of the berry
is closer than the preceding ones; it contains in the very small cells
two coloring matters, the one of a palish yellow, the other of an orange
yellow, and according as the one or the other matter predominates, the
wheat is of a more or less intense yellow color; hence come all the
varieties of wheat known in commerce as white, reddish, or red wheats.
Under this tegument is found a very thin, colorless membrane, which, with
the testa or episperm, forms two per cent. of the weight of the wheat.
No. 6 indicates the embryous membrane, which is only an expansion of the
germ or embryo No. 10. This membrane is seen purposely removed from its
contiguous parts, so as to render more visible its form and insertions.
Under this tissue is found with the Nos. 7, 8, and 9, the endosperm or
perisperm, containing the gluten and the starch; soluble and insoluble
albuminoids, that is to say, the flour.
The endosperm and the embryous membrane are the most interesting parts of
the berry; the first is one of the depots of the plastic aliments, the
second contains agents capable of dissolving these aliments during the
germination, of determining their absorption in the digestive organs of
animals, and of producing in the dough a decomposition strong enough to
make dark bread. We shall proceed to examine separately these two parts of
the berry.
ENDOSPERM OR FLOURY PORTION, NOS. 7, 8, 9.
This portion is composed of large glutinous cells, in which the granules
of starch are found. The composition of these different layers offers a
particular interest; the center, No. 9, is the softest part; it contains
the least gluten and the most starch; it is the part which first pulverizes
under the stone, and gives, after the first bolting, the fine flour. As
this flour is poorest in gluten, it makes a dough with little consistency,
and incapable of making an open bread, well raised. The first layer, No.
8, which surrounds the center, produces small white middlings, harder and
richer in gluten than the center; it bakes very well, and weighs 20 lb. in
100, and it is these 20 parts in 100 which, when mixed with the 50 parts in
the center, form the finest quality flour, used for making white bread.
The layer No. 7, which surrounds the preceding one, is still harder and
richer in gluten; unfortunately in the reduction it becomes mixed with some
hundredth parts of the bran, which render it unsuitable for making bread
of the finest quality; it produces in the regrinding lower grade and
dark flours, together weighing 7 per cent. The external layer, naturally
adhering to the membrane, No. 6, becomes mixed in the grinding with bran,
to the extent of about 20 per cent., which renders it unsuitable even
for making brown bread; it serves to form the regrindings and the offals
destined for the nourishment of animals; this layer is, however, the
hardest, and contains the largest quantity of gluten, and it is by
consequence the most nutritive. We now see the endosperm increasing from
the center, formed of floury layers, which augment in richness in gluten,
in proportion as they are removed from the center. Now, as the flours make
more bread in proportion to the quantity of gluten they contain, and the
gluten gives more bread in proportion to its being more developed, or
having more consistence, it follows that the flour belonging to the parts
of the berry nearest the envelopes or coverings should produce the greatest
portion of bread, and this is what takes place in effect. The product of
the different layers of the endosperm is given below, and it will be seen
that the quantity of bread increases in a proportion relatively greater
than that of the gluten, which proves once more that the gluten of the
center or last formation has less consistence than that of the other layers
of older formation.
The following are the results obtained from the same wheat:
Gluten. Bread.
100 parts of flour in center contain.. 8 and produce 128
" " first layer " .. 9,2 " 136
" " second " " .. 11 " 140
" " external " " .. 13 " 145
On the whole, it is seen, according to the composition of the floury part
of the grain, that the berry contains on an average 90 parts in 100 of
flour fit for making bread of the first quality, and that the inevitable
mixing in of a small quantity of bran reduces these 90 to 70 parts with
the ordinary processes; but the loss is not alone there, for the foregoing
table shows that the best portion of the grain is rejected from the food
of man that brown or dark bread is made of flour of very good quality, and
that the first quality bread is made from the portion of the endosperm
containing the gluten in the smallest quantity and in the least developed
form.
This is a consideration not to be passed over lightly; assuredly the gluten
of the center contains as much azote as the gluten of the circumference,
but it must not be admitted in a general way that the alimentary power of
a body is in connection with the amount of azote it contains, and without
entering into considerations which would carry us too wide of the subject,
we shall simply state that if the flesh of young animals, as, for instance,
the calf, has a debilitating action, while the developed flesh of
full-grown animals--of a heifer, for example--has really nourishing
properties, although the flesh of each animal contains the same quantity of
azote, we must conclude that the proportion of elements is not everything,
and that the azotic or nitrogenous elements are more nourishing in
proportion as they are more developed. This is why the gluten of the layers
nearest the bran is of quite a special interest from the point of view of
alimentation and in the preparation of bread.
THE EMBRYO AND THE COATING OF THE EMBRYO.
To be intelligible, I must commence by some very brief remarks on the
tissues of vegetables. There are two sorts distinguished among plants;
some seem of no importance in the phenomena of nutrition; others, on the
contrary, tend to the assimilation of the organic or inorganic components
which should nourish and develop all the parts of the plant. The latter
have a striking analogy with ferments; their composition is almost similar,
and their action is increased or diminished by the same causes.
These tissues, formed in a state of repose in vegetables as in grain, have
special properties; thus the berry possesses a pericarp whose tissues
should remain foreign to the phenomena of germination, and these tissues
show no particularity worthy of remark, but the coating of the embryo,
which should play an active part, possesses, on the contrary, properties
that may be compared to those of ferments. With regard to these ferments,
I must further remark that I have not been able, nor am I yet able, to
express in formula my opinion of the nature of these bodies, but little
known as yet; I have only made use of the language mostly employed, without
wishing to touch on questions raised by the effects of the presence, and
by the more complex effects of living bodies, which exercise analogous
actions.
With these reservations I shall proceed to examine the tissues in the berry
which help toward the germination.
THE EMBRYO (10, see woodcut) is composed of the root of the plant, with
which we have nothing to do here. This root of the plant which is to grow
is embedded in a mass of cells full of fatty bodies. These bodies present
this remarkable particularity, that they contain among their elements
sulphur and phosphorus. When you dehydrate by alcohol 100 grammes of the
embryo of wheat, obtained by the same means as the membrane (a process
indicated later on), this embryo, treated with ether, produces 20 grammes
of oils composed elementarily of hydrogen, oxygen, carbon, azote, sulphur,
and phosphorus. This analysis, made according to the means indicated by M.
Fremy, shows that the fatty bodies of the embryo are composed like those of
the germ of an egg, like those of the brain and of the nervous system of
animals. It is necessary for us to stop an instant at this fact: in the
first place, because it proves that vegetables are designed to form the
phosphoric as well as the nitrogenous and ternary aliments, and finally,
because it indicates how important it is to mix the embryo and its
dependents with the bread in the most complete manner possible, seeing that
a large portion of these phosphoric bodies always become decomposed during
the baking.
COATING OF THE EMBRYO.--This membrane (6), which is only an expansion of
the embryo, surrounds the endosperm; it is composed of beautiful irregular
cubic cells, diminishing according as they come nearer to the embryo. These
cells are composed, first, of the insoluble cellular tissue; second,
of phosphate of chalk and fatty phosphoric bodies; third, of soluble
cerealine. In order to study the composition and the nature of this
tissue, it must be completely isolated, and this result is obtained in the
following manner.
The wheat should be damped with water containing 10 parts in 100 of
alcoholized caustic soda; at the expiration of one hour the envelopes of
the pericarp, and of the testa Nos. 2, 3, 4, 5, should be separated by
friction in a coarse cloth, having been reduced by the action of the alkali
to a pulpy state; each berry should then be opened separately to remove the
portion of the envelope held in the fold of the crease, and then all the
berries divided in two are put into three parts of water charged with
one-hundredth of caustic potash. This liquid dissolves the gluten, divides
the starch, and at the expiration of twenty-four hours the parts of the
berries are kneaded between the fingers, collected in pure water, and
washed until the water issues clear; these membranes with their embryos,
which are often detached by this operation, are cast into water acidulated
with one-hundredth of hydrochloric acid, and at the end of several hours
they should be completely washed. The product obtained consists of
beautiful white membranes, insoluble in alkalies and diluted acids, which
show under the microscope beautiful cells joined in a tissue following the
embryo, with which it has indeed a striking analogy in its properties and
composition. This membrane, exhausted by the alcohol and ether, gives, by
an elementary analysis, hydrogen, oxygen, carbon, and azote. Unfortunately,
under the action of the tests this membrane has been killed, and it no
longer possesses the special properties of active tissues. Among these
properties three may be especially mentioned:
1st. Its resistance to water charged with a mineral salt, such as sea salt
for instance
2d. Its action through its presence.
3d. Its action as a ferment.
The action of saltwater is explained as follows: When the berry is plunged
into pure water it will be observed that the water penetrates in the course
of a few hours to the very center of the endosperm, but if water charged
or saturated with sea salt be used, it will be seen that the liquid
immediately passes through the teguments Nos. 2, 3, 4, and 5, and stops
abruptly before the embryo membrane No. 6, which will remain quite dry and
brittle for several days, the berry remaining all the time in the
water. Should the water penetrate further after several days, it can be
ascertained that the entrance was gained through the part No 10 free of
this tissue, and this notwithstanding the cells are full of fatty bodies.
This membrane alone produces this action, for if the coatings Nos. 2, 3, 4,
and 5 be removed, the resistance to the liquid remains the same, while if
the whole, or a portion of it, be divided, either by friction between two
millstones or by simple incisions, the liquid penetrates the berry within
a few hours. This property is analogous to that of the radicules of roots,
which take up the bodies most suitable for the nourishment of the plant. It
proves, besides, that this membrane, like all those endowed with life, does
not obey more the ordinary laws of permeability than those of chemical
affinity, and this property can be turned to advantage in the preservation
of grain in decortication and grinding.
To determine the action of this tissue through its presence, take 100
grammes of wheat, wash it and remove the first coating by decortication;
then immerse it for several hours in lukewarm water, and dry afterwards in
an ordinary temperature. It should then be reduced in a small coffee mill,
the flour and middlings separated by sifting and the bran repassed through
a machine that will crush it without breaking it; then dress it again, and
repeat the operation six times at least. The bran now obtained is composed
of the embryous membrane, a little flour adhering to it, and some traces
of the teguments Nos. 2, 3, 4, and 5. This coarse tissue-weighs about 14
grammes, and to determine its action through its presence, place it in 200
grammes of water at a temperature of 86°; afterwards press it. The liquid
that escapes contains chiefly the flour and cerealine. Filter this liquid,
and put it in a test glass marked No. 1, which will serve to determine the
action of the cerealine.
The bran should now be washed until the water issues pure, and until it
shows no bluish color when iodized water and sulphuric acid are added; when
the washing is finished the bran swollen by the water is placed under a
press, and the liquid extracted is placed, after being filtered, in a test
tube. This test tube serves to show that all cerealine has been removed
from the blades of the tissue. Finally, these small blades of bran, washed
and pressed, are cast, with 50 grammes of lukewarm water, into a test tube,
marked No. 3; 100 grammes of diluted starch to one-tenth of dry starch
are then added in each test tube, and they are put into a water bath at
a temperature of 104° Fahrenheit, being stirred lightly every fifteen
minutes. At the expiration of an hour, or at the most an hour and a half,
No. 1 glass no longer contains any starch, as it has been converted into
dextrine and glucose by the cerealine, and the iodized water only produces
a purple color. No. 2 glass, with the same addition, produces a bluish
color, and preserves the starch intact, which proves that the bran was well
freed from the cerealine contained. No. 3 glass, like No. 1, shows a purple
coloring, and the liquid only contains, in place of the starch, dextrine
and glucose, _i. e_, the tissue has had the same action as the cerealine
deprived of the tissue, and the cerealine as the tissue freed from
cerealine. The same membrane rewashed can again transform the diluted
starch several times. This action is due to the presence of the embryous
membrane, for after four consecutive operations it still preserves its
original weight. As regards the remains of the other segments, they have
no influence on this phenomenon, for the coating Nos. 2, 3, 4, and 5,
separated by the water and friction, have no action whatever on the diluted
starch. Besides its action through its presence, which is immediate,
the embryous membrane may also act as a ferment, active only after a
development, varying in duration according to the conditions of temperature
and the presence or absence of ferments in acting.
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