CHAPTER III 



FORM AND STRUCTURE OF MICROBES 



Animal and vegetable microbes — Protozoa— Moulds and bacteria. 

 Morphology of bacteria — Membrane ; vibratile cilia, capsules, Multiplica- 

 tion, Spores. 

 Pleomorphism -of bacteria — The place of bacteria in a general classification. 

 The nucleus in bacteria : the diffuse nucleus. 

 Reproduction and the possession of sex among microbes. 

 Chemical composition. 



" Microbes " is the name given to those living beings which 

 can only be seen by the aid of the microscope. They are the 

 simplest organisms found in nature. Some belong to the 

 animal kingdom, others to the vegetable. The bacillus of 

 tuberculosis and the typhoid bacillus belong to the class of 

 bacteria, and the bacteria are plants. The trypanosoma of 

 sleeping sickness is an infusorian, i.e., an animal. 



Whether animal or vegetable, almost all microbes consist of 

 a single cell. When there are several cells, they are practically 

 identical individual cells in juxtaposition. 



The tissues and organs are systems of cells ; microbes 

 possess neither tissues nor organs. 



Like every cell a microbe possesses a nucleus and proto- 

 plasm. 



The vegetable cell is enveloped by a membrane whose 

 composition is not well known, and even the motile ones are 

 more- rigid than the animal microbes. 



Microbes are of all living creatures the most widespread. 

 They exist wherever there is organic matter. 



Protozoa. — In a hay infusion — a handful of hay in a 



