252 GLOSSARY. 



Necrosis. The death of tissue. 



Nucleus. A concentration of vital power in a mass of 

 bioplasm. 



Objective. The object-glass of a microscope. 



Oblique Illumination. The illumination of microscopic 

 objects by light thrown from the side, either by the mirror 

 or some special contrivance. 



Oolites. Certain rocks which present a granular struc- 

 ture resembling the roe of a fish. 



Orbitolites. Foraminiferous shells of considerable size 

 occurring in tertiary limestones. 



Otoliths. Small crystalline bodies from the inner ear. 



Pabulum. The nutritive material supplied to animal 

 cells. 



Parthenogenesis. Reproduction without sexual union. 



Pathology. The science of diseased structure and func- 

 tion. 



Penetration. The property of an objective which ex- 

 hibits layers of structure below the focus. It seems to 

 depend on moderate angular aperture. 



Physical Movements. A peculiar vibratile motion in mi- 

 nute particles suspended in fluid. See Brunonian Motion. 



Polymorphism. The development of similar germs into 

 different forms by various agencies. 



Protophytes. Plants of simplest forms. 



Protoplasm. The elementary cell-material, or "physi- 

 cal basis of life." 



Protozoa. Simplest forms of animals. 



Raphides. Crystals occurring in vegetable tissues. 



Resolution. The property in a microscope of exhibiting 

 minute details, as lines, etc. 



Sarcode. A synonym of protoplasm, or cell-material. 



Sclerogen. Woody tissue. 



Selenite. Crystallized sulphate of lime. 



Spectrum Analysis. The analysis of incandescent sub- 

 stances by means of the spectroscope. 



