The “Micrococcus Rheumaticus”: Its Cultural and Other Characters

microbe under one condition an ordinary saprophyte, can raise itself not only to parasitic life, causing pathogenic action, but further to a parasitic action which is as specific as 'that of B. anthracis or B. influenzae, as, for instance, is the case with the streptococcus pyogenes. the pDeumococcus, and possibly certain species of diphtheroid bacilli. If this be the correct interpretation of the above observations, we could not oppose the view that at a very early history in the evolution -of bacteria the first branches were of the nature of "pure saprophytes," that gradually another branch became evolved out of the former, leading to the evolution of what we ,designated as " conditional parasites," and that to these latter the final and highest branch, the "specific parasites," owe their origin. We may further in this hypothesis find the explanation why manv of the specific parasites so readily revert to the stage of conditional parasitism-loss of virulence and loss of specific pathogenicity-ultimately altogether losingthe power of maintaining a parasitic life and of causing disease; and, finally, that conditional parasites may return to the state of pure saprophytes, as is the case with some Varieties of staphylococcus aureus and albus, B. coli and streptococci. There appears nothing improbable in the view that if the bacteria causing specific infectious disease, that is, the distinctly parasitic bacteria, were prevented from transmitting their species through, and maintaining their existence in, the animal body, that is to say, if they were reduced to a saprophytic mode of existence only, they would ultimately lose their power of parasitism altogether, and in consequence their power for further mischief, and specific diseases caused by them at present would spontaneously disappear in the future. We see an indication, at any rate, for this consummation in what actually occurs in those specific diseases which are imported into a country which is not endemic for the particular disease, for example, plague, cholera.