Alimentary Canal (Lat. alimentum). The tube in which the food is digested or prepared for reception into the blood.
Alkali (Arabic al kali, the soda plant). A name given to certain substances, such as soda, potash, and the like, which have the power of combining with acids.
Alveolar (Lat. alveolus, a little hollow). Pertaining to the alveoli, the cavities for the reception of the teeth.
Amœba (Gr. ἀμείβω, to change). A single-celled, protoplasmic organism, which is constantly changing its form by protrusions and withdrawals of its substance.
Amœboid. Like an amœba.
Ampulla (Lat. ampulla, a wine-flask). The dilated part of the semicircular canals of the internal ear.
Anabolism (Gr. ἀναβάλλω, to throw or build up). The process by means of which simpler elements are built up into more complex.
Anæsthetics (Gr. ἀν, without, and αἰσθησία, feeling). Those medicinal agents which prevent the feeling of pain, such as chloroform, ether, laughing-gas, etc.
Anastomosis (Gr. ἀνά, by, and στόμα, a mouth). The intercommunication of vessels.
Anatomy (Gr. ἀνατέμνω, to cut up). The science which describes the structure of living things. The word literally means dissection.