Labyrinth.  The internal ear, so named from its many windings.

Lacrymal Apparatus (Lat. lacryma, a tear).  The organs for forming and carrying away the tears.

Lacteals (Lat. lac, lactis, milk).  The absorbent vessels of the small intestines.

Laryngoscope (Gr. larugxi, larynx, and skopeo, to behold).  An instrument consisting of a mirror held in the throat, and a reflector to throw light on it, by which the interior of the larynx is brought into view.

Larynx.  The cartilaginous tube situated at the top of the windpipe.

Lens.  Literally, a lentil; a piece of transparent glass or other substance so shaped as either to converge or disperse the rays of light.

Ligament (Lat. ligo, to bind).  A strong, fibrous material binding bones or other solid parts together.

Ligature (Lat. ligo, to bind).  A thread of some material used in tying a cut or injured artery.

Lobe.  A round, projecting part of an organ, as of the liver, lungs, or brain.

Lymph (Lat. lympha, pure water).  The watery fluid conveyed by the lymphatic vessels.

Lymphatic Vessels.  A system of absorbent vessels.

Malleus.  Literally, the mallet; one of the small bones of the middle ear.

Marrow.  The soft, fatty substance contained in the cavities of bones.

Mastication (Lat. mastico, to chew).  The act of cutting and grinding the food to pieces by means of the teeth.

Meatus (Lat. meo, meatum, to pass).  A passage or canal.

Medulla Oblongata.  The “oblong marrow”; that portion of the brain which lies upon the basilar process of the occipital bone.

Meibomian.  A term applied to the small glands between the conjunctiva and tarsal cartilages, discovered by Meibomius.

Membrana Tympani.  Literally, the membrane of the drum; a delicate partition separating the outer from the middle ear; it is sometimes popularly called “the drum of the ear.”

Membrane.  A thin layer of tissue serving to cover some part of the body.

Mesentery (Gr. mesos, middle, and enteron, the intestine).  A duplicature of the peritoneum covering the small intestine, which occupies the middle or center of the abdominal cavity.

Metabolism (Gr. metabole, change).  The changes taking place in cells, whereby they become more complex and contain more force, or less complex and contain less force.  The former is constructive metabolism, or anabolism; the latter, destructive metabolism, or katabolism.

Microbe (Gr. mikros, little, and bios, life).  A microscopic organism, particularly applied to bacteria.

Microscope (Gr. mikro#3CC;s, small, and skopeo, to look at).  An optical instrument which assists in the examination of minute objects.

Molar (Lat. mola, a mill).  The name applied to the three back teeth at each side of the jaw; the grinders, or mill-like teeth.