2. Of secondary importance, entering into the more solid structures: sulphur, phosphorus, calcium, sodium, chlorine, silicon, potassium, fluorine, magnesia, iron.
3. Accidental constituents: Magnesium, alumina, copper, and lead.
The compounds found in the body are recognized as being derived from organic and inorganic substances.
Organic substances are obtained:
1. From plants and vegetables, and are termed carbohydrates or non-nitrogenous substances, being composed of Oxygen, Carbon, and Hydrogen—as starch, sugar, etc.
2. From animals: nitrogenous substances; these compounds contain Oxygen, Hydrogen, Carbon, and Nitrogen—as meat, white of eggs; these are also termed albuminous.
3. Mineral, elements of inorganic origin, as soda, potassium, phosphorus, etc.
The more highly organized tissues found in the animal are composed of five elements, as muscle, brain, blood; these are Oxygen, Carbon, Hydrogen, Nitrogen, and sulphur.
Albumen, for example, exists in most of the tissues of the body, but especially in the nervous tissue, lymph, chyle, blood, etc.
Fibrine is found most abundantly in the blood and the more perfect portions of the lymph and chyle.