Viii CONTENTS 



CHAPTER 



PAGE 



IV. MOHPHOLOGT AND CLASSIFICATION OP THE YbASTS 43 



Size, shape, and grouping of yeast cells — Structure — Cell 

 contents— Vegetative multiplication of yeast cells — 

 Development of spores — The classification of yeasts — 

 Relationships of true yeasts — Classification of the 

 yeasts — ^accharomyces — Schizosaccharomyces. 



V. Morphology and Classification of the Molds 50 



Structure of mold hyphse — Structure of the mold cell — 

 Mold growth — Multiplication in molds — Sexual repro- 

 duction in molds — Asexual reproduction in molds — 

 Sporangium formation — Conidia — Classification of the 

 molds — Key for differentiation of common genera of 

 molds — Rhizopus — Mucor — Key to species of Mucor — 

 Oospora — Aspergillus — Key to Aspergillus Species — 

 PenicUlium — Key to some coimnon species of Penicil- 

 lium — Trichothecium — Hormodendrum and Cla'dos- 

 porium — Altemaria . 



SECTION II 

 METHODS OF STUDY 



VI. CrunrRAL Methods 71 



Methods of sterilization — Sterilization by heat — Sterili- 

 zation by light — Sterilization by filtration — Culture 

 media — Nutrient substances used in preparation of 

 media — Solid media — Adjustment of the reaction of the 

 medium — Pure culture methods — Study of growth char- 

 acters. 



VII. Methods of Studying Physiologic Characters 92 



Determination of changes in hydrogen ion concentration — 

 Color changes of Clark and Lubs indicators — Deter- 

 mination of acid production — Determination of alcohol 

 production — Determination of aldehyde — Production 

 of acetyl methyl carbinol — Determination of oxygen re- 

 lationships^-Determination of gas production — Deter- 

 mination of reduction changes — Determination of indol 

 — Digestion of starch and other insoluble carbohy- 

 drates — Digestion of proteins — Fixation of atmospheric 

 nitrogen — Oxidation of ammonia and of nitrites. 



VIII. Microscopic Methods 106 



The oil immersion objective — Microscopic observation of 

 colonies and cultures — Unstained preparations — Stained 

 preparations — Spore stain — Study of acid fast bacteria — 

 Gram's stain — Staining of Flagella. 



