Pseudo-tuberculosis Hominis Streptothricha

PLATE i~d~][. The researches of the past quarter of a century have brought to light many species of microorganisms whose relations to certain pathological processes have been shown to be of the nature of cause and effect. Among these are included representatives from various groups, bacteria, protozoa, yeasts and moulds. The greatest success thus far achieved has been in the study of the bacteria; indeed, until recently these were regarded as almost the only vegetable microorganisms capable of causing infectious pathological processes. Our knowledge of the biology of the pathogenic vegetable microorganisms has more recently been extended in two directions. In the first, certain of the blastomycetes have been proven to be pathogenic for man and animals; in the second, the morphology of the bacteria has been found to depart from the simple formula originally assigned to them. In view of these facts it has been considered necessary to designate a new class for the reception of those vegetable microorganisms which, while exhibiting affinities with the bacteria, at the same time possess certain features in common with the hyphomycetes. To this class Kruse has given the name Streptothrlces. Its limits are ill-defined, chiefly for the reason that occasionally one of the common bacterial forms (B. tuberculosis, B. diphtherim, B. proteus) will show certain of the char-actezistics of the group, while for the most part they appear as simple rods. The streptot]lrices resemble the moulds in that they develop from spores into cylindrical, dichotomously-branching threads, which alternately grow into colonies the ~ppearanees Of which suggest a mass o~ radiating filaments (mycelia). Certain of the threads become fruit-hyph~e, and these break up into chains of round spore-like bodies.