Part 2

Accident. A property which is not essential to our conception of a subject.

Achene. A small, dry, indehiscent, one-seeded fruit.

Achromatic. Colorless, transmitting light without decomposing it.

Acid. A substance that neutralizes and is neutralized by a base, and which contains hydrogen. A compound that produces hydrogen ions when it decomposes in aqueous solution.

Actinium. A radioactive substance, believed to be an element.

Actinozoan. One of a class of coelenterates including the corals.

Aculeate. Having a sting, prickly.

Acuminate. Tapering to a point.

Adiabatic. Maintaining a constant temperature.

Adrenalin. A crystalline substance obtained from suprarenal extract.

Adsorption. The condensation of dissolved substances on the surface of a liquid or solid.

Adventitious. Not in the usual place, as a root.

Aerial. Atmospheric.

Affect. Disease, emotional complex.

Afferent. Conducting inward.

Agoraphobia. The morbid fear of public places.

Agronomics. The science of crop production. The scientific management of land.

Agrostology. The study of the grasses.

Air. The atmosphere, a gaseous substance of which oxygen and nitrogen are the principal constituents.

Air pump. A pump for forcing air into, or taking it out of, hollow places.

Albino. An animal, especially a human being, characterized by the congenital absence of coloring pigment in the skin, hair, and eyes. The typical albino has very light skin and hair and pink eyes.

Albumen. A substance, usually edible, found between the skin embryo of seeds.

Albumin. A class of proteids found in blood serum, milk, and muscle.

Alcohol. Ethyl alcohol, the substance which causes intoxication, and a whole class of substances which are similar to it. They are hydroxides of organic radicals.

Alga. Seaweed. Chiefly used in the plural: algae.

Alkali. Caustic hydroxides which form soluble soaps with fatty acids and turn red litmus paper blue.

Allotropy. Variation of physical properties without change of substance. Carbon, for example, may exist as lampblack, graphite, or the diamond.

Alloy. A mixture (not a compound) of metals.