^LI B RAR.T
OF THL
UN IVER.SITY
or ILLINOIS
,itiB.««4i '.vi'iaTra. av-:vteJi;,-x-'"S'Si«,.'fLj
The person charging this material is re-
sponsible for its return to the library from
vJhich it was withdrawn on or before the
Latest Date stamped below.
Th.«, mutilolion, ond underlining of books
oro reoions (or disciplinary atlion ond moy
resiill in dlsmlssol Iron, tiro University.
UNIVERSITY OF UUNOIS LI»I!A.Y AT U»BANA-CHA«P<.IGN
MAY \
m
FEBl
219?5
EB 1 1 1975
loEc 0 4 m
L161 — O-1096
THE LlBRftRY Of Ti'-i:
FEB ;i* 1930
UNIVERSITY OF ILUNO'.S
INDIAN CORN
BY
JAMES B. McNAIR
Assistant Curator of Economic Botany
Botany
Leaflet 14
FIELD MUSEUM OF NATURAL HISTORY
CHICAGO
1930
LIST OF BOTANICAL LEAFLETS ISSUED TO DATE
No. 1. Figs $ .10
No. 2. The Coco Palm 10
No. 3. Wheat 10
No. 4. Cacao 10
No. 5. A Fossil Flower 10
No. 6. The Cannon Ball Tree 10
No. 7. Spring Wild Flowers 25
No. 8. Spring and Early Summer Wild Flowers . . .25
No. 9. Summer Wild Flowers 25
No. 10. Autumn Flowers and Fruits 25
No. 11. Common Trees 25
No. 12. Poison Ivy 25
No. 13. Sugar and Sugar- Making 50
No. 14. Indian Com 25
STEPHEN C. SIMMS. Director
FIELD MUSEUM OF NATURAL HISTORY
CHICAGO. U. S. A.
I
LIBRARY
OF THE
u.N!v:.'^siTy OF Illinois
Courtesy of Indiava Faryner's Guide
CORN IN THE SHOCK
Field Museum of Natural History
DEPARTMENT OF BOTANY
Chicago, 1930
Leaflet Number 14
Copyright 1930 by Field Museum of Natural History
Indian Corn
CONTENTS
Page
Origin, Geographic Distribution and Varieties 2
] Use by the American Indian 14
Modern Industrial and Experimental Products 19
r
^
THE imm Of THE
FEB 2 * 1930
UNIVERSITY OF UUNOtS
[215]
ORIGIN, GEOGRAPHIC DISTRIBUTION,
AND VARIETIES
Origin. — When the white man reached America he
found com cultivated by the Indians in many widely
separated areas. Its history before that time remains
mostly a matter of conjecture. The numerous Indian
myths fail to throw much light on the subject, but testify
to the importance and antiquity of corn on this continent.
Every Indian myth that attempts to explain the origin
of agriculture deals with corn. Among the Quiche of Guate-
mala tradition relates that certain gods or godlike men,
recently arrived in the land and much displeased with
living conditions, planned to reclaim the natives from
barbarism. After mature deliberation, four barbarian
chiefs were sent to a distant land to get new ideas. They
returned bringing with them the "ears of yellow maize
and white," which rounded out their scheme of existence
and became their chief reliance for food. Another tradi-
tion of the Quiche makes com the very breath of life.
Made of earth, man was without life; but by means of
maize he was converted into flesh and blood.
In an account of the South American Canari tribe,
two brothers escaped the Deluge by climbing a mountain
in Ecuador. When the waters subsided, they descended
in search of food. Two parrots repeatedly visited the
famishing men, giving them food and drink made of
maize. One of the birds was captured, whereupon she
miraculously changed herself into a beautiful woman.
She gave the men the seed of maize, taught them its
culture and uses, and ultimately became the ancestress
of the Canari race.
The Navajos say that they first knew of com when
a turkey hen came flying from the direction of the morn-
ing star and shook from her feathers an ear of blue com.
[216]
i4^
Indian Corn
In a tradition of one tribe of the United States, the
Great Spirit comes to earth in the form of a woman and
falls asleep. On waking, she arises and walks through
the land, while useful plants spring up around her. At
the right and left grow pumpkins and beans, and from
her footprints comes maize.
Upon the return of his first expedition in 1492,
Columbus reported the growing of maize in Cuba. Alvar
Nufiez (Cabeza de Vaca) described it as planted by
Indians in Texas in 1527. Cartier in 1534 found it in
Canada, and in 1585 Hariot gave a good description of
it on Roanoke Island, while in 1607 Captain John Smith
wrote of it around Jamestown.
Charred com has been found in the remains of the
Mound Builders of Ohio and the Mississippi valley.
Dried com has been found in the pueblos of the south-
west and in the burials of Peru. At Tarapaca, Chile,
corncobs have been found buried beneath an ancient
lava flow. Darwin found, on the coast of Peru, ears of
com together with eighteen species of recent seashells,
imbedded in a beach which had been raised to at least
eighty-five feet above the level of the sea, through move-
ment of the earth, and this com was identical with that
taken from old Peruvian tombs. A petrified ear of com
was found at Cuzco, Peru. These findings place the
cultivation of this plant in America at an early date.
By botanists com is considered to be a highly
specialized cultivated grass. For centuries it has been
dependent upon man, not only for improvement, but
for the continuation of life itself. As a result, com at
present exists in a form which it did not have before
the coming of the Indian to the New World.
Com is thought to have originated either in the
western mountains of South America or in Mexico or
Central America. Wild plants very closely related to
com have been found only in America — on the table-
[217]
Original in Field Museum
ANCIENT PERUVIAN JAR
Indian Corn 5
lands and in the foothills of Central America and south-
eastern Mexico. One of these plants, teosinte (Euchlaena),
hybridizes with com. This has led those who have
studied plants to believe that com originated there.
As corn was one of the chief foods of the Indians,
it is not strange that it played a decorative part in
their pottery and sculpture. It also played a part in their
religion and so is found the com altar of the American
Indian — the six-direction altar. Six ears of com were
placed on the ground as follows: yellow pointing north,
blue pointing west, red pointing south, white pointing
east, black pointing northeast, indicating above, and
sweet com pointing southwest, indicating below. Corn
was used in many other ceremonies. The Aztec god of
agriculture is sometimes represented with a stalk of
com in one hand. Centeotl was the Ceres of the Aztecs,
their goddess of com. The Mayas and Peruvians also
made extensive use of corn in their festivities.
United States. — Com is the outstanding crop of the
United States, both as to value and acreage. In both
value and area it exceeds the combined crops of wheat,
oats, rye, barley, buckwheat, rice, fruits, and nuts. Since
the first official registration in the United States, in 1840,
of the number of agricultural products and their value,
corn has led all other cereals in importance, and since
1865 there has been a noticeable increase in production
in proportion to the population.
Although corn may be grown under widely varied
climatic conditions, the best results are obtained only
within limited areas. In the United States the best com
is grown in those parts of the country which have an
average summer temperature of seventy to eighty degrees,
an average night temperature of over fifty-eight degrees,
a frost-free season of at least 140 days, and a yearly
[219]
6 Field Museum of Natural History
rainfall of twenty-five to fifty inches, of which seven to
eight inches fall in July and August. The soils best
suited to corn are dark, fertile loams or silty areas, well
supplied with heat and moisture, and well drained.
Thus the ideal conditions for extensive corn production
occur only in a few parts of the world, and are found to
the greatest extent in the United States. Within such
areas the corn crop reduces the production of other
cereals, especially those which must be grown during the
same season of the year, to a negligible position, since
com yields about twice as much grain and, with the
fodder, more than three times as much food per acre as
either wheat or oats.
The United States produces about three-fourths of
all the corn in the world. Although the exact temperature,
soil, and moisture conditions described above are found
only in certain parts of the country, corn of one or another
variety is grown to a greater or less extent practically
throughout the entire United States. The Mississippi
valley is the great com country, producing three-fourths
of all the corn grown within our boundaries. Within the
Mississippi valley are two centers of maximum com
production, one in central Illinois and the other including
western Iowa and eastern Nebraska. In 1909, the area
devoted to corn-growing in Illinois comprised 10,046,000
acres, or 10 per cent of all the land given to com pro-
duction throughout the country. In Iowa were 9,229,000
acres of com; in Kansas, 8,109,000 acres; in Nebraska,
7,226,000 acres; in Missouri, 7,114,000 acres; and in
Indiana, 4,901,000 acres. The corn acreage of these six
states combined was 47 per cent of the total for the
country, and their com production 57 per cent of the
total. As an effect of this large-scale production, a
system of live stock farming has developed which makes
[220]
Indian Corn 7
use of com products. One-third of the beef cattle and
about one-half of the swine in the country are raised in
these states.
Although a large percentage of the total crop is
produced in these middle and western portions of the
country, com is grown in almost the entire eastern part
of the United States. Moreover in certain eastern regions,
the acreage devoted to com, in relation to the total
acreage given to crops, is greater than anywhere else,
although the actual acreage and production are small.
In mountainous eastern Kentucky, where the rural
population depends for its livelihood largely upon the
cultivation of small fields of com, 75 per cent of all the
land under cultivation is given to this product. In
Florida, southern Alabama, and Mississippi, where the
land is still largely covered by forests, com occupies 50
per cent of such land as is sown in crops.
In spite of the fact that com is the main source of
food supply in the United States, outside of the southern
states very little of the com produced is directly con-
sumed by man. Most of the crop is used in feeding
live stock, and may be said to be ultimately consumed
by man in the form of beef, a pound of which represents
the consumption of ten or twelve pounds of com, or as
pork, a pound of which requires, in its production, five
or six pounds of com. A large percentage of the com
produced in the Illinois and Iowa "com belts" is shipped
to near-by industrial centers, particularly Chicago, to be
converted into starch, glucose, and com meal. Some
of the com is exported in its natural state, but by far
the greater portion of the crop is fed to animals, and
reaches the market in that less perishable form. In the
South, however, practically all the com is consumed at
home, in the various forms of "hog, hominy, and hoecake."
Europe. — The production of com is also carried on in
Europe, in such territories as possess climatic conditions
[221]
8 Field Museum of Natural History
favorable to this pursuit. Europe as a whole produces
about one-fourth as much com as the United States.
The chief corn-growing countries are Hungary, Roumania,
southern Russia, and Italy, all of which, as to soil, rain-
fall, and temperature, have similar conditions to those
in the com belts of the United States. Among these
nations, Hungary leads in acreage and production. In
Roumania, however, corn plays a more important part
in the industrial life of the nation, since it is a main
source of food and also one of the chief exports of that
country. Forty per cent of the cultivated land is here
sown in com, and Roumania produces about four times
as much corn, in relation to her population, as does
Hungary. In Russia, most of the com is grown in Bessa-
rabia, not only because of the favorable climatic condi-
tions found there, but also because of convenient location
for shipping. Fifty per cent of Russian com is shipped
to other countries, while Roumania exports about 40 per
cent of her total crop.
Smaller contributors to the European corn supply are
Italy, where com is grown principally in the valley of
the Po, and where irrigation is often necessary; France,
whose small quota is produced partly in the north and
partly along the Mediterranean coast; and Spain and
Portugal, where the grain can be grown only along the
western and northern coasts.
Egypt and India. — The Egyptian corn crop is produced
altogether by means of irrigation. The grain is planted
in July, irrigated about every ten days, and harvested
in October and November. India has considerable corn
acreage, although it occupies only about 3 per cent of
the land under cultivation. Here com is grown in the
silty soil along the Ganges, and by irrigation in the
region of the Punjab. It is used principally for human food.
[222]
Indian Corn 9
Mexico. — Although Mexico ranks second only to the
United States in the percentage of cultivated land given
to the production of com, the yield in that country, due
to primitive agricultural methods, is relatively small.
Most of the com is grown by peons on the small patches
which they lease from the owners of large ranches. Irriga-
tion is often used. A great part of the crop is used for
the making of com bread (tortillas) which is a favorite
article of food in Mexico. The com lands are situated
in the southern part of the country, on the high table-
lands, and in Yucatan. In spite of the extensive acreage,
and although very little com is exported from Mexico,
the native crop is insufficient to supply the needs of the
country, which regularly imports about one million bushels
annually from the United States.
Canada. — In Canada, com is grown chiefly in Ontario,
under climatic conditions very similar to those found in
the northern states. Most of the yield is used for silage,
or fed, fresh from the field, to the farm animals.
Argentina. — Argentina ranks second to the United
States in the production of com per capita of the popula-
tion. Corn-growing here is centered in Buenos Aires,
Santa F^, and Cordoba, where the mild climate and the
ishght variability in temperature form very favorable
conditions for a large yield. Twenty-one per cent of the
cultivated land in Argentina is sown in com, and this
percentage shows a tendency to increase. The com is
planted from September to December. The average
summer temperature is seventy-five degrees, and the
annual rainfall of thirty to forty inches contributes to
the success of the industry, although the greater part of
the rain comes rather late in the com season. Because
of the small population, much of the com is exported,
and the flinty type grown in this section is particularly
adapted for transportation without great loss. In 1912,
Argentina exported 64 per cent of her total crop.
[223]
POD CORN. EACH KERNEL IS ENCLOSED IN A HUSK
Indian Corn 11
Varieties of Corn. — Almost fifty years ago Dr. Sturte-
vant divided Indian com into seven groups, each of
which has well-developed and lasting characteristics:
pod corn (Zea tunicata), pop com (Zea everta), flint com
(Zea indurata), dent com (Zea indentata) , soft corn
(Zea amylacea) , starchy-sweet com (Zeaamyleasaccharata),
and sweet com (Zea saccharata) .
1. Pod corn. — In this group each kernel is inclosed in
a pod or small husk and the ear thus formed is inclosed
in a large husk. This type is considered by some to be
the original type of corn.
2. Pop corn. — This species group is characterized by
the large proportion of a tough, homy substance (corneous
endosperm) in the starchy portion of the kernels, and by
the small size both of the kernels and of the ear. The
best varieties for popping have the homy substance
throughout the starchy portion of the kernels. The
property of popping, which is the complete eversion or
turning inside out of the kernel, is caused by the explosion
of the contained moisture through the application of heat.
3. Flint corn. — A species group readily recognized by
having the starchy portion of the kernels inclosed by a
coating of a horny substance, as shown in a split com
seed. This homy portion varies in thickness with the
varieties. It cannot be confused with any other species
except the pop corn, from which it is set apart by the
larger kernel and inability to pop. In drying there is
no shrinkage of the top of the grain and no dent forms.
4. Dent corn. — A species group recognized by the
presence of homy substance at the sides of the kernel,
the starchy portion extending to the summit. By the
drying and shrinkage of the starchy matter the summit
of the kernel is drawn in or together, and indented in
various forms. In different varieties the horny substance
varies in height and thickness, thus determining the
character of the indented surface.
[225]
POP CORN
DENT CORN
POP CORN
SOFT CORN
FLINT CORN
SWEET CORN
Indian Corn 13
5. Soft corn. — This species group is at once recognized
by the total absence of horny material. Due to the uni-
formity of the shrinkage in ripening, there is usually no
indentation; yet in some varieties an indentation may
more or less frequently appear, but on splitting the kernel
the soft com may always be recognized.
6. Starchy-sweet corn. — A well-defined species group
characterized by the translucent, homy appearance of
the kernels, and their more or less wrinkled or shriveled
condition.
7. Sweet corn. — A well-defined species group char-
acterized by the translucent, homy appearance of the
kernels and their more or less crinkled, wrinkled, or
shriveled condition.
All seven of these groups of com were grown by the
Indians of North and South America. The certainty of
sprouting is highest in pop and flint corns, lower in
sweet corn, and poorest in dent corn, and the decrease in
the starchy content of the kernels is in this order: pop,
flint, dent, soft, starchy-sweet, and sweet.
At the present time, pop com is extensively grown in
the United States for that purpose. Almost all of the
field corn in the United States is of the dent type. Flint
requires a smaller number of days to mature a crop, and
is consequently more used farther north and at higher
elevations above sea level. It is the common field com
in New England. Dent and flint furnish all the grain of
commerce and practically all the fodder and ensilage.
Sweet corn forms the basis of a large canning industry
in the North Atlantic and North Central states. It is
less generally grown in the Southern states. Soft corn
was preferred by the Indians because of its ease of grinding.
[227]
USE BY THE AMERICAN INDIAN
Stalks, Leaves, and Husks. — The Indians commonly
wasted the stalks, leaves, and husks except for a limited
use in mats, beds, thatching, and fuel. In Mexico and
parts of South America the large, outer husks were and
are still used for wrapping tamales for cooking. The thin,
inner husks were used for cigarette paper. Like its near
relative, sugar cane, cornstalks produce sugar. Prescott
writes of the Aztecs obtaining juice from the stem, which
was boiled down to a syrup or fermented and used as a
drink.
Ears and Kernels. — The roasting ear was everywhere
a favorite food of the Indian. Com was eaten raw,
boiled, or roasted, and the Indian invented the mixture
of green corn and beans known as succotash. Parched
com was widely known and used in many ways.
Meal. — Several different methods were used by the
Indians in making corn meal. In Pennsylvania, a vessel
containing sand was heated. The corn was then mixed
with this sand and slowly heated until the grain burst.
The burst grain was then taken out and ground to a
fine powder. In another method the .corn was first par-
boiled, the water drained off, and the grain dried. The
dried kernels were roasted on a plate, ashes being mixed
with them to prevent burning. The grains were stirred
constantly and soon acquired a red color, at which time
they were removed and well rubbed. They were then
mixed with the ashes of the dried stalk of the kidney
bean, a little water was added, and the mixture thoroughly
pounded into meal. Among the Indians of the south-
western United States, the blue com was used. This
when rubbed in a stone mortar gave a meal of bluish-gray
color. A second method used in this same section of the
[J28]
Indian Corn 15
country was to cook the com in limewater until the hard
covering was removed; then the grain was pounded into
white flour. This last method is used by the white man
in preparing hominy.
The food use of corn meal varied in different parts
of the country. The various ways of making bread were
as follows: in the neighborhood of Pennsylvania the
meal was kneaded with water into dough. This dough
was made into round cakes about six inches in diameter
and about an inch thick. They were then baked in clean
wood ashes. Dough was sometimes mixed with pieces of
pumpkin, beans, chestnuts, huckleberries, etc. Indians
also mixed smoked eels and shellfish, chopped fine, with
their corn meal in the making of bread.
The mestizas of Mexico made similar corn bread in
various shapes and sizes, known as gorditas. In the
southwestern United States and Mexico thinner cakes
called tortillas were also made. In their manufacture a
thin batter was used, dipped from a bowl by the hands
and spread in a thin layer on a hot stone or plate. The
mass quickly puffs up, a sign that one side is done, and
it is then turned over, while the second cake is placed
on to bake. Thinner cakes were made of blue starch
com by the Hopi Indians in Arizona. These thin cakes
were rolled up like thin jelly rolls and were known as
piki bread.
Pinole was corn meal cooked or mixed with sugar from
the mesquite (Prosopis juliflora D.C) or other source. The
Central American Indians added a red coloring matter,
arnatto, to this mixture and called it yixte. In Mexico
such a mixture without coloring matter was cooked and
wrapped in small pieces of corn husk, in the form of a
necklace, for ease of transportation when traveling. These
were known as saules.
Various forms of pottage in which corn meal was the
basis were familiar to the Indian. In the northeastern
[229]
#5lfe<^
V**'*.** '.* ' •••'•^»**'«»*.»', • • • '^•v*'''*J'^.* *-*•,'-'* *'^
Codex Fejervdry — Mayer, pp. 31,-33
A PRECONQUEST MEXICAN MAIZE ALMANAC
Illustration of maize from a preconquest Indian codex from southern
Mexico representing the story of the corn plant from planting to harvest.
The figures read from right to left, the upper row being an allegorical
series of figures representing corn in its several stages. In the first
sketch of the series the corn plant is small, scantily clothed and bent
(immature), while in the third sketch it is larger, fully clothed and
erect (mature). Along with the corn plant are shown the rain goddess,
_g6;^^uAq ft (D » A
'E^,:S:±^'
^i^ft § %
flower goddess, and the chief rain god. These were agricultural deities,
who protected the maize crop. In the left top panel are shown various
birds and rodents, which destroy the young plants. The lower row rep-
resents important Mexican divinities. According to J. Eric Thompson
the time interval between each of the upper series of illustrations is
65 days. The four intervals together make 260 days, the "tonalamatl"
or sacred year of the Aztecs and other Central American peoples, used
in divination and for regulating times for sowing crops, etc.
i
18 Field Museum of Natural History
section of the country the meal was boiled with fresh or
dried meat (the latter pounded), dried pumpkins, beans,
or chestnuts. Sometimes the mixture was sweetened with
maple syrup or sugar. An appetizing dish was made by
boiling well-pounded hickory nut kernels with corn. In
the southwestern United States and in Mexico meal was
often cpoked with pieces of meat with red or green peppers
or other vegetable. When this is wrapped in corn husks
and boiled it is known as a tamale. Bread was also made
from crushed, fresh, undried corn.
Beverages. — Although the Indians realized the sub-
stantial way that corn supplied some of their essential
needs, yet their keenest sense of pleasure came from the
drinks that it afforded. They had a great many of these.
One god is said to have given the Mexicans nine excellent
recipes at one visit. Probably the most commonly used
fermented drink was chicha, which was widely known in
many forms. There were many ways of preparing it.
The dry, parched, or sprouted com was either ground
or masticated and then mixed with water and allowed
to ferment. This was highly intoxicating.
[232]
MODERN INDUSTRIAL AND EXPERIMENTAL
PRODUCTS
Like the Indian, the white man still makes meal from
the com kernels, but many other substances are also
manufactured from it, such as starch, dextrine, glucose,
sugar, oil, and solvents. From the cobs, pipes, xylose,
sugar, and other articles can be made, while from the
stalks, cane sugar, wall board, paper, artificial silk, and
numerous other articles are manufactured. Let us begin
with products obtained from the grain.
USE OF CORN KERNELS
In 1925 the United States produced 2,900,581,000
bushels of corn, valued at $1,956,326,000. The firms
producing com syrup, com sugar, com oil, and starch
valued their products at $132,873,000. Of this amount
$95,778,000 was the value of starch and the sugars and
syrups obtained from starch by the acid action.
The substances which make up the kernel vary widely
in amount in accordance with breeding and cultivation;
the following, however, is an average composition in parts
per hundred:
Per cent
Water 19.6- 10.2
Ash 1.2- 1.3
Oil 3.0- 4.5
Starch 60.0- 65.0
Pentosans 7.0- 7.5
Fiber 1.2- 1.5
Protein 8.0- 10.0
Total 100.0-100.0
Starch and Oil. — Starch manufacture consists of the sep-
aration of starch from the other substances of the kernel.
At the end of the process of manufacture a bushel of com
yields:
[233]
20 Field Museum op Natural History
Pounds
Starch 32,5
Feed (20.8 lbs.)
Gluten meal 6.9
Corn bran 5.8
Germ oil meal 2.0
Steep water 5.3
Corn oil 1.5
Total 54.0
In America the earliest processes for manufacturing
starch embodied, first, the steeping in water of the grain
at 77''-140° F., followed by grinding between rollers
or buhr-stones, and the ground product washed in cylinder
sieves. In sieving the hulls were separated from the starch.
Next the starch and water mixture was run upon inclined
troughs, and the starch granules deposited at the bottom
of the troughs while the lighter gluten fiber ran off. The
starch which had settled in the troughs was washed with
a weak alkali solution to further remove gluten. Finally
the starch was washed repeatedly with fresh water.
The method in general use now is known as the sul-
phurous acid method, first used in Europe. This was
modified and improved and now consists of cleaning,
steeping, grinding, sieving, tabling, washing, and drying.
In cleaning the grain, fanning mills and sieves are
used to separate chaff and light particles. Electromagnets
draw out any iron which would injure the grinding
machinery. The clean grain is taken to large, copper-
bottomed steeping vats and steeped for thirty to forty
hours with water containing 0.25 per cent to 0.30 per
cent sulphurous acid (SO2). The sulphurous acid is used
to prevent the formation of mildew or slime. By means of
steam, the mixture is kept circulating and heated to a
temperature between 115°-125° Fahrenheit. The heat-
ing is done to soften the corn. The steep water contains
the salts, soluble carbohydrates, and proteins, which pass
out through the covering membranes of the corn kernel.
This hquid contains about 20 per cent ash, 38 per cent
[234]
Indian Corn 21
protein, and 49 per cent carbohydrate and non-protein
material. This water solution is concentrated by evapora-
tion to a syrup and sprayed upon the com gluten feed
before drying.
The kernels softened by steeping are passed to Fuss
mills. These mills are made up of two parallel vertical
plates which rapidly revolve in opposite directions, and
carry studs which project between each other. In these
mills the kernel is broken, although the tough, rubbery
germ at the tip of the grain passes out entire. The germ
contains practically all of the oil in the grain and is
extracted from the rest of the grain in germ separators.
The germs are lighter in weight and are thus separated
by the steaming process and ground in oil mills to express
the oil. By far the most part of the oil is refined and
sold as edible oil for use in salads and cooking. Unrefined
com oil is used for soap-making and for nearly all pur-
poses to which a semi-drying oil is adapted. The oil-
press cake is used for cattle feed. After the removal of
the germs the remainder, which consists of starch, gluten,
and fiber, is mixed with water and ground again in buhr-
stone mills.
The thick, liquid mass is now passed over the shakers,
which are tilted bolting cloth sieves of about 200 mesh,
placed in a shaking apparatus. The starch and most of
the gluten are washed through the bolting cloth. The
fibrous portion tumbles off the lower end of the sieve.
The liquid containing starch and gluten is passed
from the shakers to inclined troughs, or tables. These
wooden tables are about 100 feet long and 2 feet wide,
with vertical sides. As the heavy liquid flows slowly
down the tables the starch granules are deposited, while
the gluten tends to pass down and off the tables. When
the deposit of starch has become about ten inches thick,
[235]
22 Field Museum of Natural History
the flow of starchy Hquid is stopped, the gluten remain-
ing on the surface of the starch is scraped off, and the
deposited starch flushed off the table with water.
The water containing gluten which comes from the
starch tables is returned, after proper treatment, to the
steeping vats. The starch after it comes from the settling
tables is broken up and spread out upon trays made of
wood and burlap. These trays are placed in carriers or
wagons, and moved through kilns or drying tunnels in
which a constant current of hot air is kept up. When
a wagon and its contents are thoroughly dry, they are
removed from the opposite end of the tunnel.
Commercial Forms of Dried Starch. — In accordance
with variations in the time and temperature of drying,
different starches are formed. "Pearl starch" is dried
about twenty hours at approximately 170° Fahrenheit.
"Crystal starch" is formed when wet starch is placed
in kilns in the form of a compact cube and drying con-
tinued for a matter of weeks. Finally the mass contracts
and breaks up into distorted prisms called crystals.
The size of the crystals varies with the temperature, a
low heat forming larger crystals. "Powdered starch"
is made from "pearl starch" by pulverizing and sifting.
"Lump starch" is made by treating powdered starch
with steam and high pressure. The solid cylinder of
starch which results is crushed and screened to size.
Various Uses of Starch and Starch Modifications. —
Starch when treated with acids or alkalis forms purified
starches, soluble starches, thin-boiling starches, and
alkaline thick-boiling starches. Dextrines are made by
roasting slightly acidified starch under various degrees
of temperature and pressure. Several forms of starch
are used in the textile industries for stiffening and finish-
ing warp and cop yarns; as a filler, finisher, and size in
paper-making; for food uses in the manufacture of baking
[236]
Indian Corn 23
powders, pie fillings, pastes, sauces, jellies, and puddings;
for laundry purposes; for dusting molds in foundries;
and in the production of asbestos products, oilcloth,
linoleum, explosives, paints, soaps, adhesives, coal
briquettes, etc. Several varieties of dextrines are made
use of in textile industries for sizing and stiffening the
fiber, finishing the fabric, thickening the colors in calico
and other printing, dressing leather, and in pastes, gums,
glues, ink, fireworks, etc.
Solvents. — Besides the above use for starch, there is
another in which starch is transformed into solvents or
lacquers used to a great extent in the automobile industry.
Com although used to its greatest extent as a feed for
animals and a food for man is not always fit for these
purposes, as large quantities become spoiled. Previous
to 1918, this low-grade com was used to a large extent
in the making of whiskey and starch and its by-products.
But now the solvent industry has become one of its
largest users.
Besides low-grade com unfit for consumption other
carbohydrates may be used as raw materials for this
process. The com is first screened to remove dirt and other
fine matter, next passed through a magnetic separator
to remove pieces of iron and steel, and finally ground in
roller mills. The product from the roller mills is screened
to separate the flour, and the larger particles are returned
to the mill for further grinding. The membrane covering
the kernels (bran) after separation from the flour is sold
for feed. Generally whole corn is used in this process, but
part of the corn may be degermed and only the starch
used. All the com is not degermed because the germs
contain protein, and too large a reduction in the amount
of protein in the process would be objectionable, for
protein is necessary to the growth of the micro-organisms
[237]
24 Field Museum of Natural History
used in the process. As much of the com is degermed
as possible, however, as the oil obtained from the germs
more than pays for the cost of separating it.
A great amount of com meal is carried from the
storage bins to the mashing vats. In the vats warm water
is added and when the mixture has been made up to its
proper consistency, the material is dropped into cookers.
In the cookers, which are inclosed autoclaves, the material
is cooked for two hours by live steam under pressure. This
cooking is done to sterilize the material as well as to bring
it to the proper condition for fermentation. At the end of
the heating period the charge is blown by its own pressure
from the cookers to the fermenters. On its way to the
fermenters the sterile starch solution is cooled to below
blood heat. At this point the mixture has about the
consistency of ordinary flour paste. It is of interest to
note that no malt is used and that the solution to be
fermented contains starch and not sugar. Precautions
are taken at the pipe lines, and storage vessels and fer-
menters are protected from contamination by any wild
yeast and fungi.
The micro-organism used in the process to transform
starch into solvents (butanol, acetone, and alcohol) is
a bacterium, Clostridium acetobutyricum (Weizmann). A
pure culture of this micro-organism is obtained, and
before addition to the sterilized starch solution a large
quantity of the micro-organism is obtained, so that it
will outgrow any foreign micro-organism that might be
present to contaminate the mixture.
The Clostridium changes 3 pounds of starch into 1
pound of mixed solvents in the form of a 2 3/^ per cent
solution. During this change a gaseous mixture of 45
per cent hydrogen and 55 per cent carbon dioxide is given
off. The liquid solvent mixture obtained as a 23^ per cent
solution consists of approximately 60 per cent butanol,
[238]
Indian Corn 25
30 per cent acetone, and 10 per cent ethanol. After
fermentation the solution passes to a large reservoir
from which it is pumped to stills. This is the only point
in the process where mash is pumped. These stills are
columns eight feet in diameter and fifty-four feet high.
The 23^ per cent solvent mixture in passing through the
stills is changed to a 50 per cent mixture. The resultant
mixture is later fractionated in other stills into its three
principal constituents, namely butanol, acetone, and eth-
anol. This separation is made easier because of the fact
that butanol and water form two layers.
By-products are formed at three stages in the process.
The first by-product is the bran or outer membrane of
the kernel which is separated from the corn in the grind-
ing process. The second by-product is the mixture of
the hydrogen and carbon dioxide gases formed in the
fermentation, and the third by-product is the waste from
the stills. The bran, as already said, is sold for feed.
The profitable disposition of the hydrogen and carbon di-
oxide gases and the still waste are more complex problems.
The hydrogen is readily separated from the carbon dioxide
by the solution of the carbon dioxide in water. The
hydrogen may find its commercial use in the manu-
facture of ammonia. By passing the mixed hydrogen
and carbon dioxide gases over heated carbon, a mixture
of carbon monoxide and hydrogen is secured, which
might serve for the manufacture of methanol. The
waste from the stills contains about 1 per cent solid
matter. These particles of solid matter may be removed
readily by passing the waste through a fine screen. The
particles collected in this way are nutritious and may be
sold as feed.
USE OF CORNCOBS
The com crop estimates of the United States govern-
ment are based on bushels of shelled com. For each
bushel of shelled com fourteen pounds of cobs have been
[239]
26 Field Museum of Natural History
harvested. For the four years 1923-27, an average of
2,676,200,000 bushels of corn has been brought to
market annually. Such an amount would be obtained
from a yearly harvest of 19,000,000 tons of corncobs. Of
this number approximately 1,444,800 tons of cobs were
received at the grain elevators scattered throughout the
corn belt. From these grain elevators the cobs could
readily be obtained for manufacturing purposes.
Tobacco Pipes. — Corncobs are perhaps best known in
the form of tobacco pipes called Kentucky or Missouri
"meerschaums." However, they use but a very small
fraction of the annual product of corncobs.
Fuel. — At the present time corncobs have their
greatest use as fuel. In the western states the fuel supply
used to be uncertain and many cobs, as well as full ears
of corn, were used as fuel. In fuel value three tons of corn-
cobs equal one ton of hard coal. In France, the cobs,
soaked in resinous matter (sixty parts melted resin and
forty parts tar) were formerly used as fire lighters and
were bought at from twelve to twenty francs.
Potash. — Corncobs contain a large amount of potash,
in fact more potash than any other mineral constituent.
Mills which shell corn frequently use cobs as fuel. A
mill shelling 5,000 bushels an hour has 7,000 pounds of
cobs per hour. The ashes in the mill are collected for
the extraction of potash. One thousand cobs yield 7.62
pounds of potassium carbonate, or in a factory of the
above capacity, 535 pounds per ten-hour day. Experi-
ments have been carried on with the use of impure
corncob ashes as a water softener.
Meat-smoking. — Meat-smoking and bee-smoking have
been carried on successfully by the use of corncobs.
Insulating Material. — During the last few years a
product has appeared in the Chicago markets made out
of corncobs to be used for insulating houses already con-
[ 240 ]
Indian Corn 27
structed. It is called kalkite, with the accredited com-
position of nineteen parts corncobs, twelve parts gypsum,
and two parts waste paper and chemicals. Corncobs,
bought at grain elevators for a dollar a ton loaded on the
cars, are ground up to the fineness of granulated cork. The
gypsum acts as a binder, and together with the other
chemicals makes a product vermin-proof and practically
fireproof. Houses are insulated with this material
without disturbing the contents. Holes are bored in the
plate between the studs in the attic, and the wall space is
filled with a mixture of kalkite and 10 per cent water.
The space between the floors is filled with the material
in similar manner. On a floor the product weighs about
4^ pounds per square foot. Kalkite has been tested by
the United States Bureau of Standards and shows a heat
conductivity of forty British thermal units per hour, per
square foot, per one inch in thickness, per one degree
Fahrenheit change in temperature.
Miscellaneous Uses. — Corncob flour has been substi-
tuted for wood flour in many ways, for example as a
basis for punk and incense and in curing concrete
floors in place of sawdust. Corncob flour has also been
substituted for bran in removing oil from tin plate in the
tin-plating industry. Corncobs heated with water and
steam under pressure produce a powerful adhesive.
When corncobs are subjected to destructive distillation,
products similar to those obtained from wood are secured,
that is, charcoal, acetic acid, wood alcohol, tar, illumi-
nating gas, and alcohol. The charcoal has been found to
be an excellent medicinal charcoal. Under suitable
treatment it forms a very good decolorizer.
Xylose or Wood Sugar. — This sugar may be obtained
from corncobs by boiling them with dilute sulphuric
acid. It is found occurring naturally in the nucleo-
proteids of plants and animals, and is perhaps the only
[241]
28 Field Museum of Natural History
sugar made up of five carbon atoms to be found in
animals. It is about one-half as sweet as cane sugar^
whereas glucose from starch is three-fourths as sweet as
cane sugar. Xylose does not ferment with yeast and
therefore is probably indigestible and without food value
to man. It may, however, be of use as a sweetener for
the food of persons suffering from diabetes. Xylose may
be obtained not only from corncobs but also by the
action of dilute sulphuric acid on bran, straw, and various
other vegetable products.
Fwr/wra/.— Furfuraldehyde or furfural is formed when
xylose is distilled with hydrochloric (muriatic) acid or
with dilute sulphuric acid (vitriol). It is more practical
to obtain furfural by distilling a mixture of dilute hydro-
chloric acid and ground corncobs. The distilling vapor
is condensed to a mixture of furfural and water which
may be fractionated to produce almost pure furfural.
Furfural, like formaldehyde, will form a hard resin
similar to bakelite. The resin formed can be used in
varnishes or when added to a suitable filler such as wood
or corncob flour as a molding resin. Resin may be formed
from furfural by the addition of phenol (carbolic acid),
or may be made directly in the ground cobs by the
addition of hydrochloric acid and phenol.
Furfural acts as a preservative, and has been used in
veterinary embalming fluid and for other purposes. It
is also a solvent for nitro-cellulose and cellulose acetate.
As a solvent it removes varnish readily. During the war
it was used in "dope" for airplane wings. The Chemical
Department of the Iowa State College has made a num-
ber of dyes and anaesthetics from furfural. It has been
used as an accelerator in rubber curing. It can also be
used as a fuel to replace gasoline, although its expense
makes it impractical for present use for that purpose.
When added to gasoline it forms an anti-knock motor
fuel.
[ 242 ]
Indian Corn 29
The yield of furfural from corncobs is about 10 per
cent of their weight. An equivalent amount can also be
produced from oat hulls and other material. This is
about half the laboratory or theoretical yield. Cotton-
seed bran yields 22 per cent, which is double the amount
from corncobs. Because oat hulls and cottonseed hulls
are produced over a large period each year, they are
more desirable as a source of furfural than corncobs,
which are only at present available in the elevators from
November to May.
THE USE OF STALKS
Syrup. — Most of the different plants of the grass
family have hollow stems, but there are three notable
exceptions: sorghum, sugar cane, and corn. All three
contain cane sugar. The Aztecs in Mexico made use of
the corn plant for sugar, in the same manner as sugar
cane is now used. An interesting review of the trade in
com sugar in Colonial days is given by Collier in his book
on sorghum sugar. Work carried on at the Minnesota
Agricultural Experiment Station resulted in the following:
a cannery which cans only com has available approxi-
mately 500 acres of stalks or 4,000 tons per year, which
could produce 1,100 gallons of syrup per day, or 38,000
during a season. In the Minnesota experiments five
varieties of sweet com and two of field com were used.
When the com is ripe enough to can, the juice of the
stalks contains 9-11 per cent cane sugar. If the stalks
stand in the field twenty days after the removal of the
ears, the amount of sugar in the stalk increases to 13-17
per cent. The proper stage for syrup-making is during
the time of maximum amount of sugar in the juice, not
only because of the yield but because of the quality of
the juice. Cornstalk syrup may be manufactured by
nearly the same process as sorghum syrup. The con-
trolled defecation, filtration, and vacuum evaporation
may be used. Cornstalk syrup is clear, reddish amber in
[243]
30 Field Museum of Natural History
color, with a pleasant flavor. As produced, it is not a
table syrup but an excellent cooking syrup considered
equal to the best grades of sorghum and cane molasses.
As estimated by the Minnesota Experiment Station, the
commercial manufacture of cornstalk syrup is not very
profitable. They assume that three dollars per ton of
fresh stalks would be satisfactory to the grower. This
would amount to eighteen or twenty-one cents per gallon
of syrup. Actual cost of manufacture is considered as
thirty cents. The total cost is consequently about fifty
cents per gallon, and could sell wholesale at about sixty-
eight cents to compete successfully with the best grade
of sorghum syrup. If the manufacturing plant cost
$60,000 the returns at sixty-eight cents per gallon for
syrup would be about 11 per cent. These figures allow
for the utilization of bagasse and leaves.
Wall Board. — The usual height of cornstalks in the
Com Belt is from six to ten feet, although the plant has
been known to grow anywhere from eighteen inches to
twenty-four feet high. The stalk consists of a hard outer
shell inclosing a center of soft pith. This outer shell is
made up of many bundles of long, thin fibers and micro-
scopic tubes called fibrovascular bundles. Some fibro-
vascular bundles also appear in the pith. The leaves on
the cornstalk are attached every eight or ten inches along
the stem. At these points of attachment the fibrovascular
bundles going to the leaves from the stem form hard,
dense portions, known as nodes. The soft pith is com-
posed of flat, non-fibrous cells.
As tall office buildings have frameworks of steel, so
cornstalks have frameworks of cellulose fibers. Conse-
quently cellulose makes up 45 per cent of their total
weight. It is interesting to note that various woods
contain 48-62 per cent of cellulose. Another constituent
of cornstalks is lignin, to the extent of 31 per cent, which
[ 244 ]
Indian Corn 31
equals the average content of lignin in woods. Char-
acteristic constituents of cornstalks are their pentosans,
which make up over 27 per cent of their weight, while in
common woods the percentage varies between 7 and 25.
The chemical difference between the hard portion of the
stalk and the soft pith apparently is slight, while their
physical characters differ very greatly. Com leaves are
lower in cellulose than the stalks or husks. The cobs also
have a lower cellulose content, but are higher in pentosans.
A chemical analj^sis of cornstalks and cobs shows them
to be not greatly different from wood.
Wall board can be made from cornstalks by the use
of machinery, water, heat, and pressure. By the use of a
paper beater or rod mill the long, strong fibrovascular
bundles are torn apart by shredding and beating in water.
The beating is continued until the fibers are of the proper
length. In so doing they have absorbed a large quantity
of water and become slightly sticky on the surface. When
pressed together and dried, they form board. Cooking
under pressure increases the property of sticking together.
The use of such board as building material has rapidly
developed. A short time ago wall board and insulating
board were used only in temporary partitions or in cheap
repair work, and were considered suitable only for such
uses. Today, however, a great deal is used in the making
of houses of the better sort. The heat and sound insulating
properties of such materials are due to the minute air
pockets between the fibers, which efficiently interfere with
the circulation of air and heat and the transmission of
sound. Other, similar boards are made from wood,
wheat straw, flax straw, sugar cane waste, licorice root
waste, cork, etc. These boards when used in buildings
form a substitute for lath and plaster or serve as a plaster
base or as sheathing either beneath wooden siding or
under stone or brick veneer.
[245]
32 Field Museum of Natural History
A hard, dense form of board has been made with the
joint appHcation of heat and pressure in a special type
of hydraulic press. Such boards resemble a very hard,
grainless wood, suitable for use as panels. Another form
of useful material is made by impregnating the felted
material with synthetic resin.
Paper. — Besides wall board, cornstalks can be made
into paper. Experiments have been conducted by the
United States government in cooperation with Iowa
State College, where the entire cornstalks have been
made into paper without any attempt at separation of
the parts. Good paper can be made by various processes.
Excellent paper of the quality used in books and writing
paper may be produced by the "soda process." This
method involves cooking the stalks in caustic soda or
lye. Paper made by a somewhat modified "soda process,"
called the Dorner process, now appears for sale. The
Kraft method furnishes a good brown wrapping paper.
A cheap mechanical pulp paper suitable for newspapers
is being developed.
Artificial Silk. — Further refinement of paper pulp
results in a substance known as alpha cellulose. Alpha
cellulose is the basic material for rayon, or artificial silk.
The commercial output of rayon at present comes from
wood and cotton. Experimental work in a rayon factory
showed that high-grade rayon can be made from corn-
stalk pulp by any of the three methods now in common
use.
Statistics on Cornstalk Production. — The United States
produced annually an average of 2,676,220,000 bushels
of corn for the four years 1923 to 1927, inclusive. Assum-
ing that 84 per cent of the crop was harvested for grain,
and that the stover-grain ratio was 150, the amount of
stover produced annually would be 94,000,000 tons. If
one-third of the weight of stover consisted of water at
the time it was harvested, there would be not less than
[246]
Indian Corn 33
62,000,000 tons of bone-dry material for use in wall
board, paper, or artificial silk manufacture. One ton of
cornstalks is said to make 2,000 square feet of wall board.
The yearly production of cornstalks in Iowa available
for manufacture is estimated as 10,000,000 moisture-free
tons. Iowa could therefore make each year from unused
cornstalks 20,000,000,000 square feet of wall board.
The average yield of stalks per acre is calculated at
a minimum of one and one-half tons. In Iowa one-third
of the land is considered as planted in com. Therefore a
manufacturing plant in operation 300 days a year could
obtain eighty tons of stalks a day from within a five-mile
radius or 335 tons a day within a ten-mile radius. In
that part of Iowa where 60 per cent of the land is planted
in com, a radius of five miles will give 150 tons of stalks
a day and ten miles will yield 600 tons of stalks a day.
According to these estimates, the length of haul to supply
even a fairly large factory would be short.
To determine the proper method of harvesting corn-
stalks, the Agricultural Engineering Department of Iowa
State College carried on an extensive study. As a result,
a machine has been made which both cuts and bales the
stalks as it goes over the field. The machine is a com-
bination of a mower, a hay loader, and a baler, made into
one, and pulled by a tractor. Two men are needed to oper-
ate the machine. Cost of operation is considered to be
$2.40 per ton.
On the farm the immatiu^e, green stalks together with
the grain are used in making silage, a very good food for
farm animals. The mature, fully grown stalks from which
the ripe ears of com have been gathered have very little
food value, but do have a commercial value in the manu-
facture of wall board and paper. At the present time they
are for the most part ploughed under for fertilizer or
burned to clear the field for the spring ploughing.
James B. McNair
[247]
THE UBRWY Of Wt
UNIVERSITY or auNo^s
An exhibit of corn and products derived from corn kernels such
as oil, starch, glucose, and alcohol is to be found in Hall 25 in Field
Museum. In Hall 28 will be found the various industrial products
derived from cornstalks, cobs, kernels, and husks such as wall board,
paper, and solvents.