Herbivorous (Lat. herba, an herb, and voro, to devour).  Applied to animals that subsist upon vegetable food.

Heredity.  The predisposition or tendency derived from one’s ancestors to definite physiological actions.

Hiccough.  A convulsive motion of some of the muscles used in breathing, accompanied by a shutting of the glottis.

Hilum, sometimes written Hilus.  A small fissure, notch, or depression.  A term applied to the concave part of the kidney.

Homogeneous (Gr. ho#1F41;mos, the same, and genos, kind).  Of the same kind or quality throughout; uniform in nature,—­the reverse of heterogeneous.

Humor.  The transparent contents of the eyeball.

Hyaline (Gr. hyalos, glass).  Glass-like, resembling glass in transparency.

Hydrogen.  An elementary gaseous substance, which, in combination with oxygen, produces water.

Hydrophobia (Gr. hydor, water, and phobeomai, to fear).  A disease caused by the bite of a rabid dog or other animal.

Hygiene (Gr. hygieia health).  The art of preserving health and preventing disease.

Hyoid (Gr. letter u, and eidos, form, resemblance).  The bone at the root of the tongue, shaped like the Greek letter u.

Hypermetropia (Gr. hyper over, beyond, metron, measure, and ops, the eye).  Far-sightedness.

Hypertrophy (Gr. hyper, over, and trophe, nourishment).  Excessive growth; thickening or enlargement of any part or organ.

Incisor (Lat. incido, to cut).  Applied to the four front teeth of both jaws, which have sharp, cutting edges.

Incus.  An anvil; the name of one of the bones of the middle ear.

Indian Hemp.  The common name of Cannabis Indica, an intoxicating drug known as hasheesh and by other names in Eastern countries.

Inferior Vena Cava.  The chief vein of the lower part of the body.

Inflammation (Lat. prefix in and flammo, to flame).  A redness or swelling of any part of the body with heat and pain.

Insalivation (Lat. in and saliva, the fluid of the mouth).  The mingling of the saliva with the food during the act of chewing.

Inspiration (Lat. inspiro, spiratum, to breathe in).  The act of drawing in the breath.

Intestine (Lat. intus, within).  The part of the alimentary canal which is continuous with the lower end of the stomach; also called the bowels.

Iris (Lat. iris, the rainbow).  The thin, muscular ring which lies between the cornea and crystalline lens, giving the eye its special color.

Jaundice (Fr. jaunisse, yellow).  A disorder in which the skin and eyes assume a yellowish tint.

Katabolism (Gr. kataballo, to throw down).  The process by means of which the more complex elements are rendered more simple and less complex.  The opposite of anabolism.