Lectures On Bacteria

d without reference to their origin or future destination. They are forms of the vegetative development, growth-forms as they may be shortly termed, and correspond to those which in the higher plants are designated by the words tree, shrub, bulbous plant, and the like. Forms which are determined only by their conformation correspond indeed only to separate members of a particular growth, such as woody stem, tendril, tuber, bulb, andc. If we wish to know the significance of a tendril or a bulb in the chain of phenomena, or indeed that of any other form of living creature, we must answer the above questions of its origin and destination, or, to use the customary form of words, we must learn the course of its development. For every form of living being taken at any one moment of time, though it may be present in millions of specimens, is only a member of a chain of periodic movements which coincide with a regular alternation of forms. If therefore we wish for a more intimate acquaintance with Bacteria, we must proceed to enquire into their course of development. As far as our present knowledge goes, this development is not quite the same in all cases. We must distinguish two groups, one of which contains the Endosporous, the other the Arthrosporous Bacteria. The former group consists of a number of straight rod- forms which will here receive the special name of Bacillus, and a few screw-twisted Spirilla. The phenomena, so far as theyare known, are essentiall...