THE AFFINITIES OF THE BACTERIA So far but little mention has been made of the classification of bacteria, the reader will find this adequately given in any text book. All that need be said here is that the system or systems of classification adopted are based on no sure foundation, there being among bacteria, in contrast with other plants and animals, no clear indications as to the sequence in which various groups or families have arisen in the course of evolution. Similarly the affin ities of bacteria with other forms of life are quite obscure; on the one hand they bear certain likeness to the protozoa, one group, the Spirochoetes, which used to be classed as bacteria has even been transferred to the protozoa, mainly on the ground of their character of dividing longitudinally as do the protozoa instead of transversely, the method universally present in the bacteria; on the other hand, as stated earlier, bacteria seem to possess affinity to the fungi, both being non-chlorophyll-containing plants. Wheth er the bacteria have evolved by degeneration from some more elaborate form of fungus, or whether they are to be regarded as the primitive form from which other forms of life have developed, are questions which have formed the basis of much discussion.
One group of bacteria which Thaxter has named the Myxobac teria shows very close relationship to a certain group of fungi, the Myxomycetes or slime fungi. The slime fungi are masses of naked protoplasm, or plasmodia, which at a stage in their life history form cyst-like bodies in which the whole of the pro toplasm changes into the form of spores. The Myxobacteria behave in a very similar way, equally elaborate spore-containing cysts are formed and in fact the characters of the group are those of the Myxomycetes except that a bacterial zoogloea takes the place of the plasmodial mass of the slime fungi. This group then seems to form one end of a bridge connecting the bacteria with the fungi and it is in fact the sole indication of any such affinity which up to the present has been discovered. (S. G. P.)