250 GLOSSARY. 



lariscope tests this property and exhibits it in many sub- 

 stances. A thin film of selenite intensifies it if it is not 

 strong enough to show color otherwise. 



Epiphytes. Parasitic plants. 



Epithelium. The layer or layers of cells covering ex- 

 ternal or internal surfaces of animal bodies. 



Epizoa. Parasitic animals. 



Focal Distance. The distance from the centre of a lens 

 to the focus, or point of distinct vision. 



Foraminifera. Shells of minute animals, chiefly calca- 

 reous, which are perforated with minute pores for the pro- 

 trusion of threads of sarcode or bioplasm. 



Formed Matter. The structure produced by the action 

 of bioplasm, or by the influence of external agents upon it. 



Fraunhofer's .Lines. The dark lines which cross the 

 solar spectrum, corresponding to the chemical nature of 

 the burning substance. The blackness of the lines de- 

 pends on the incandescent vapor of the substance. 



Gemmation, or Budding. A term given to the repro- 

 duction of cells by the protrusion of a part of their sub- 

 stance, which becoming constricted, falls oft' and lives an 

 independent life. 



Germinal Matter. Another name for bioplasm, or " cell- 

 stuff." 



Herapathite. The iodo-disulphate of quinia. 



Histo-Chemistry. The science which investigates the 

 chemistry of the tissues. 



Histology. The science of tissues. 



Immersion Lens. An objective arranged so as to re- 

 quire a drop of fluid interposed between its front lens 

 and the covering glass of the object. 



Indifferent Fluids. Fluids which produce little or no 

 change in animal or other tissues. 



Infiltration. The deposition of material from the blood 

 into various tissues. 



Lens. A piece of glass ground and polished so as to 



