CHAPTER IV 



PHYSIOLOGY OF THE MICROBES 



Nutrition— The definition of food material — Nutrition of the Mucedinese — 

 Raulin's experiments — Bearing of these experiments — Nutrition of 

 yeasts and bacteria — Importance of the chemical constitution of the 

 medium— The bacterium of sorbose — The idea of the ' soil ' — Respira- 

 tion — Aerobic and anaerobic life. 



The purple bacteria, 



Secretion of diastases or enzymes. 



Products of the cultures — Products of excretion. 



Auto-intoxication of the cultures. 



Production of heat — Production of light — Production of pigment. 



Action of heat on microbes ; thermophil microbes. 



Action of light ; ultra-violet rays. 



Physiology of Protozoa : cells possessing a great abundance of diverse 

 functions — much differentiated — Nutrition ; digestion, respiration 

 Irritability — Reproduction — ^ Parasitism — Adaptations and specificities 

 — Life cycle and secondary host — Cultures. 



The microbes act in nature as transformers of energy. The 

 energy which they get from oxygen and from various food 

 materials they transform into products of excretion, heat, 

 light, and work, retaining a portion used up in the building of 

 their own substance. Like the higher creatures they display 

 anabolism and catabolism. Each one is like a little vortex, 

 from which the organic matter emerges different from its state 

 on entry. It is characteristic of living beings to transform the 

 molecules of their food materials into more complicated 

 molecules. For example, from sugar they produce cellulose, 

 from carbohydrates along with the nitrogen of ammonia they 

 prepare the nitrogenous compounds. 



To construct these new arrangements of the molecule, energy 



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