724 GLOSSARY. 



Amoeba. A unicellular organism consisting of a nucleated mass of 

 protoplasm. 



Amorphous. Without definite or regular form ; the opposite of 

 crystalline. 



Amylolytic. Relating to the conversion of starch into dextrin and 

 grape-sugar. 



Amylopsin. A ferment in the pancreatic juice, which converts 

 starch into sugar. 



Analgesia. A condition of the nervous centres in which pain can- 

 not be felt, but ordinary tactile and other sensations remain un- 

 impaired. 



Analysis. A separation into component parts ; the splitting up of 

 a chemical compound into its constituents. 



Anastomoses. The direct union of bloodvessels without the inter- 

 vention of a capillary network. 



Anelectrotonns. A peculiar electric condition of a nerve, resulting 

 from the passage of a current through the nerve, but confined 

 to the region where the current enters, i.e., the neighborhood 

 of the positive pole. 



Anode. The positive pole or electrode i.e., the pole by which the 

 electric current enters a substance. 



Apncea. A state of cessation of the breathing movements from 

 non-excitation of the respiratory nerve centre on account of an 

 unusually arterial state of the blood. 



Area opaca. The outer zone of the blastoderm from which the 

 foetal membranes are developed. 



Area pellucida. The central spot of the blastoderm from which 

 the embryo chick is developed. 



Arteriole. A small artery ; usually applied to those vessels the 

 walls of which are largely composed of muscle tissue. 



Arthroses. Movable joints which have a synovial membrane. 



Asphyxia. A term meaning, literally, cessation of the pulse, such 

 as occurs from interruption of respiration, now commonly used 

 as synonymous with suffocation. 



Assimilation. The chemical combination of new material (nutri- 

 ment) with living tissues. This forms the most characteristic 

 property of living matter. 



Astigmatism. Unevenness of the refracting surfaces of the eye ; 

 when engaging the entire cornea, it is called "regular," and 

 affecting a local part, t- irregular " astigmatism. 



Atoms. The ultimate indivisible particles of matter. 



