phosphoric acid. If, on the other hand, his corn is planted primarily and chiefly for the grain, he learns that phosphoric acid is required in a proportion nearly equal to that of all the other elements together, and that next to this in importance are potash and soda.

An inspection of these tables will also throw some light upon the relative feeding values of corn-stalks, and the straw of the other included grains, as well as upon the comparative nutritive values of the grains themselves.

The proportion of ash contained in any plant or grain represents the amount of inorganic matter that enters into its composition. When the plant is burned, all the other constituents, amounting generally to over ninety per cent. of the entire weight, disappear. We are thus able to determine what grains contain the smallest proportion of inorganic matter, and are consequently least exhausting to the mineral elements of the soil.

In the following table, Prof. Johnston has given the quantity of ash yielded by one thousand pounds of each of the plants named:

The investigations of Dr. Jackson, of Boston, in regard to the properties of corn, are equally curious and instructive. Among other interesting facts, he

has shown that the proportion of phosphates in each variety of maize depends on its assimilating power. It was found that of two varieties of corn (Tuscarora and sweet) growing on the same cob, the former had less than half the amount of phosphates contained in the latter.

To those who have not seen the report of Dr. Jackson, a brief statement of his further researches will perhaps be interesting.

In most of the yellow varieties, the oil is the seat of color, the hull or epidermis being transparent. In the white varieties, the oil being colorless and pellucid, and the hull transparent, the farinaceous portion of the kernel, which is white, gives a similar appearance to the grain. In the hæmatite varieties the red, purple, and blue colors are chiefly derived from the epidermis.

The proportions of oil vary from six to eleven per cent.; the flint corns of the North being found to contain more than the Southern varieties. The oil is analogous to animal fat, and is readily converted into that substance by a slight change of composition.

The gluten and mucilage contain nitrogen, which is necessary to the formation of fibrous tissue, muscle, nervous matter, and brain.

Starch is convertible also into fat and into the carbonaceous substances of the body, and during its slow combustion in the circulation, gives out a portion of the heat of animal bodies; while, in its altered state, it goes to form a part of the living frame. Sugar acts in a similar manner as a compound of carbon,

hydrogen, and oxygen, in the formation of fat of animal bodies.

From the phosphates the substance of the bones and the saline matter of the brains, nerves, and other solid and fluid parts of the body are in a great measure derived.

The salts of iron go to the blood, and constitute an essential portion of it, whereby it is enabled by its changing degrees of oxidation, during its passage through the lungs, arteries, and veins, to convey oxygen to every part of the body.

Thus it appears that in each kernel of corn all the elements have been deposited by Nature, that are essential to a healthful, invigorating, and nutritious 'food.

LIBRARA

UNIVERSITY OF

CALIFORNIA.

DEVELOPMENT AND STRUCTURE.

THE vital principle of maize is lodged in the embryo, or rudiment, a small, clearly defined interior division of the seed, or kernel. This embryo is the starting point of life and growth. It extends from the base of the grain upward, about two-thirds of the distance toward the crown, and lies in contact with the epidermis on one side of the kernel, through which it can be distinctly traced by the eye.

The earliest movement of the seed in developing the new plant is termed germination. When the plant has advanced so as to form leaves that contribute to its growth, the process is termed vegetation.

Three conditions are essential before germination can take place. The presence of heat,* moisture, and air is indispensable. After the seed is planted, and these agents have had time to exert their quickening influence, a small root shoots out, with a very rapid growth, from the base of the embryo, and, after another interval, the stem rises slowly from its apex.

* 48° Fahr. is about the limit of temperature, below which corn will not germinate.

The progress made by the roots during the first few days is quite remarkable. They not unfrequently attain to a length of fifteen or eighteen inches before the stem has made three inches above the surface of the ground.

From the relative positions of the stem and the early roots, the former springing from the crown, and the latter from the base of the embryo, it is evident that the most natural and favorable position of the grain for incipient growth is with the base downward and the crown above. When this condition is reversed, as continually occurs in planting, the stem and root are each compelled to describe a curve, sometimes equal to a half circle, in order to acquire their normal position. When this position is reached, if the seed should be turned over, the stem and root would again promptly bend themselves through another curve, to recover once more the situation natural and indispensable to their proper growth.

That the position of the kernel when planted is calculated to affect the progress of germination is an obvious and natural conclusion. The author has found, in some experiments having reference to this point, that grains planted in an inverted position are retarded from ten to fifteen hours in the time of their appearance above ground, as compared with others planted in an upright position.

As soon as the germination of the seed begins, the stem, obeying a natural instinct, springs upward toward the sunlight, while the roots, equally obedient to an instinct of their nature, travel downward into