CONTENTS. 



pigment production. Phosphorescence. Heat produc- 

 tion. Toxicogenic ani pathogenic bacteria. 



CHAPTER VI. 



The Microscope. — The Hanging Drop. — Simple 



Staining ... ... 123 



Simple and compound microscopes. Spherical and chro- 

 matic aberration. Achromatic and apochromatic objectives. 



Under-correction. Magnifying power, equivalent focal 



distance.^ — Defining power. Resolving and penetrating 



power, Numerical aperture.- Designation of objectives. 



Huyghenian eye-piece. Compensating eye-pieces. 



Designation of oculars. 



Abbe condenser, iris diaphragm; Structural and colored 



images. Rules for use of condenser, to secure illumination. 



T^he stand, graduation of draw-tube. Coarse and fine 



adjustment. Nose-piece. Care of microscope. 



Measurement of an object. Stage and ocular microme- 

 ters; Micromillimeter or micron. Micrometer value of 



an objective. 



Slides and cover-glasses. Cleaning of the latter. 



Cover-glass forceps for bacteriological work. 



Examination of living bacteria. The hanging-drop. 



Laboratory work. 



Staining of bacteria. Acid and basic anilin dyes. 



Stock solutions. Dilute stains. Simple staining. Labor- 

 atory work. 



CHAPTER VII. 



Gelatin and Potato Media. — Cultivation of Bacteria . 152 



■ Preparation of the meat extract. Alkalization. 



Cleaning and plugging of tubes. Dry and moist heat steriliza- 

 tion. Fractional sterilization at 100°, at 60°. Steam steril- 

 izer. The autoclave. 



Preparation of potato media. Dilution and mass cul- 

 tures. The pure culture. Precautions in work. Labora- 

 tory work. 



Gelatin plate cultivation. Advantages over potato and 



liquid media. Glass plates' 'Platinum wires. Dilution in 



gelatin. Pouring on plates. Plating apparatus. Moist 



chambers. Apparatus for constant low temperature. 



Laboratory work. 



Modified gelatin plate method. Petri dishes. Esmarch 



roll-tubes. Laboratory work. 



