MORPHO-BIOLOGICAL CORRESPONDENCE BETWEEN TWO OR MORE MICRO- ETIOLOGICAL ORGANISMS NOT SUFFICIENT GROUNDS FOR PRONOUNCING THE DISEASES WITH WHICH THEY ARE CONNECTED IDENTICAL. The details of this discussion will be found in my report on the swine-plague. It is necessary, however, to touch upon the essential points here also. As was there shown, Hueppe asserts that the European diseases previously mentioned as being caused by a member of this group of belted, ovoid germs, viz., the “ Huhne Cholera, Kaninchen Septikasmie, und Wild Seuche ’ ’ are all one and the same disease, because their micro-etiological organisms have the same form, the same size, the same belted appearance, and because they all grow alike in bouillon, upon agar-agar, and in beef-infusion gelatine. No greater or more misleading and illogical pathological miscon, ception could possibly be made, than this statement of Hueppe with regard to the diseases named. It may be axiomatically asserted that the most complete morphological resemblance, and exact morpho-biological resemblances, in or upon any artificial media, are not sufficient grounds for any such generalization in classification of diseases as that attempted by Hueppe. To all beginners in the work of patho-bacteriology, and to all older hands as well, I most dogmatically assert that there is but one factor in the biology of micro-etiological organisms which can decide whether two apparently alike germs are one and the same object when derived from two distinct diseases of animal life. That factor is a physio-chemico-biological one!