CONTENTS. 





Pigment production. Phosphorescence. Heat produc- 

 tion. Toxicogenic and 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. Denning 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. 



The 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. 



