Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. Excerpt from book: Section 3IL CLASSIFICATION. The earlier naturalists—Ehrenberg (1838), Dujardin (1841)— placed the bacteria among the infusoria; but they are textit{noiv recognized as vegetable microorganisms, differing essentially from the infusoria, which are unicellular animal organisms. One of the principal points in differentiating animal from vegetable organisms among the lowest orders of living things is the fact that animal organisms receive food particles into the interior of the body, assimilating the nutritious portion and subsequently extruding the non- nutritious residue ; vegetable organisms, on the other hand, are nourished through the cell wall which encloses their protoplasm, by organic or inorganic substances held in solution. Ehrenberg (1838), under the name of vibrioniens, established four geu- era, as follows: 1. textit{Bacterium—filaments linear and inflexible. 2. textit{Vibrio—filaments linear, snake-like, flexible. 3. textit{Spirillum—filaments spiral, inflexible. 4. textit{Spirochcete—filaments spiral, flexible. Dujardin (1841) united the two genera textit{Spirillum and textit{Spirochcete of Ehrenberg, and added to the description of the generic characters as follows: 1. textit{Bacterium—filaments rigid, with a vacillating movement. 2. textit{Vibrio—filaments flexible, with an undulatory movement. 3. textit{Spirillum—filaments spiral, movement rotatory. It will be seen that this classification leaves no place for the motionless bacilli, such as the anthrax bacillus and many others, and does not include the spherical bacteria, now called micrococci. The classification of Davaiue (1808) provides for the motionless, filamentous bacteria, but does not include the micrococci. This author first insisted that the vibrioniens of Ehrenberg are truly vegetable organisms, allied t...