LIBRARY 



UNIVERSITY OF 1 



VLIFORNIA. 



GLOSSAEY. 



Aberration (ab, from, and <?rro, to wander). The errors 

 resulting from the imperfection of lenses. They are of 

 two kinds, chromatic and spherical aberration. 



Abiogenesis. The dogma of spontaneous generation, or 

 the alleged production of living beings without pre-exist- 

 ing germs. 



Absorption Bands. Transparent substances are usually 

 opaque to certain colored rays of light, that is, absorb 

 them ; and when they are submitted to prismatic analy- 

 sis, this opacity causes gaps in the spectrum. Some sub- 

 stances produce absorption lines of great sharpness, while 

 others have an indistinct outline. 



Achromatic. Destitute of chromatic aberration. 



Alternation of Generations, or Metagenesis, is a term em- 

 ployed to designate a cycle of phenomena in which one 

 generation does not produce a form like itself, but one 

 whose progeny are similar to the generation preceding. 



Ameboid Movements. Motion in minute masses of bio- 

 plasm, resembling that of Amoeba. It has been recognized 

 in Yolvox, in Chara, in the roots of mosses, in fungi, as 

 well as in colorless blood-cells. 



Amyloid Infiltration. A filtration of waxy or lardaceous 

 albumin ate from the blood among certain tissues of the 

 body. 



Angular Aperture. The angle made by the diameter 

 of the actual aperture of an objective and the distance 



