412 THE MICROSCOPE. 



Tyndall, and others, that bacteria are present in certain 

 ferments, whether of a putrid, lactic, acid, fatty, or 

 viscous nature. The consequence is that they have a 

 high amount of interest for the medical profession, the 

 microscopist, and the sanatarian. 



Bacteria can be at any time readily developed by in- 

 fusing a small piece of fresh beef in water, or by adding 

 the fibrine of blood of an animal to water, and letting 

 the solutions stand by in a warm place for about 

 four- and- twenty hours. Certain forms of bacteria 

 exhibit greater signs of vitality in dark moist places, 

 and ihey are almost invariably found in all river- waters 

 polluted by sewage, and in waters in any way contami- 

 nated by animal refuse. 



Monads vary in colour, some are red, green, or yellow, 

 others nearly colourless. In shape they are round or 

 oval (5 and 6, fig. 226), are very active, and are furnished 

 with one or more flagella. 



VIBRIO. Vibriones. In this family Ehrenberg oddly 

 enough includes eels in paste and vinegar. 



Vibrio spirilla, Trembling animalcules, are now classed 

 among bacteria, and are claimed by the botanist ; when 

 exerting the powers of locomotion they take a spiral 

 form, like the threads of a fine screw, and by undula- 

 tions wind themselves through the water with rapidity. 

 They are almost invariably found in decaying acetous 

 and putrefying organic matters. When treated with 

 iodine and sulphuric acid, their jointed structure 

 becomes visible to the highest powers of the micro- 

 scope. 



ASTASI.SA. Astasia, signifying without a station, in 

 contradistinction to those living in groups, is the term 

 given to a kind of crimson-coloured animalcule, the 

 350th of an inch in length, that exist in enormous 

 numbers, and give the waters in which they live the 

 appearance of their bodies. Ehrenberg described 

 several varieties of them. 



EUGLENA. The Euglence of D ujardin in some respects 

 Correspond with the Astasice of Ehrenberg ; while other 

 observers refer Euylence to the vegetable and Astasics 

 to the animal kingdom. The euglena, like bacteria, are 



