19

from the atmosphere, must be supplied artificially by what are
called, and are then manures.

Although the ten last named elements form but a very small
per centage of living bodies, yet they are absolutely essential in
their existence; for without phosphate of lime and magnesia,
which is a compound of phosphorus, calcium and oxygen, neither
the bones of animals nor the seeds of grass nor of grains would be
formed. Without sulphur no nutritive food capable of yielding
blood or brain matter could be produced. Without silicate of
potash and soda no stem of wheat, no blade of grass nor stalk of
corn could exist.

It may be interesting here to state the various parts and secre-
tions of the body in which the different mineral constituents occur.

Phosphate of Lime occurs most largely of all the mineral con-
stituents of the human body. It is found in the bones, blood,
milk, urine, faeces, &c.

Carbonate of Lime forms the principal part of the skeleton in
the invertebrata, (animals who have no spine,) such as crabs, oys-
ters, &c. It also occurs in the bones of higher animals and man,
in egg shells and the urine of those animals which feed on grass.

Phosphate of Magnesia is very frequently associated with phos-
phate of lime. It occurs in bone, blood, milk, egg shells, urine,
&c.

Fluoride of Calcium sometimes occurs in very small quantity
in bones. It is abundant in fossil bones.

Hydrochloric Acid exists in the digestive fluid of man and all
animals that give milk to their young.

Chloride of Sodium (common salt) exists in the blood, gastric
juice, urine, bone, cartilage, (gristle,) &c.

Carbonate of Soda is found in various animal substances, espe-
cially in the urine of animals that feed on grass.

Phosphate of Soda occurs in the lymph, bile, chyle, milk and
urine.

Chloride of Calcium is found in the gastric juice and saliva.

Chloride of Iron is found in the gastric juice.
Alkaline Sulphates are found in blood, sweat, urine, &c.
Iron is found in considerable quantities in the coloring matter
of blood, in chyle, black pigment of the eye, hair, &c.

Chloride of Potassium is found in almost all of the animal
fluids.

Silica has been found in the enamel of teeth, in bone, hair and
saliva.*

The above compounds contain all of the substances which I
have before named as necessary to constitute a fertile soil, viz:

* Simon's Chemistry of Man