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be justified. Cases, observed by myself, in which a definite point of entry of the B. pestis could be found, are not confirmative of such a view. So far, my cases showed a definite lymphangitis previous to the occurrence of the bubo. It was slight, but if looked for carefully, could not be missed. An instance of such has already been given under the heading of the "Symptom Complex of Plague.
"J
The persistent absence of anything like an acute lymphangitis in cases of bubonic plague, is, in my opinion, strong evidence against the skin inoculation theory of plague causation. Further lymphangitis has been found present in the lymphatic apparatus leading from the small intestine. This fact is in favour of an alimentary mode of entry of the virus.
Skin infection in plague only after some definite breach of continuity of the skin has occurred. For instance the presence of ragged nails, abrasions, minute wounds are liable in plague infected areas to be infected with plague bacilli and thereby lead to a case of the disease. In the absence of more definite evidence, the question of skin infection in plague appears to be exaggerated.
WILLIAM HUNTER.
The Bacillus Pestis.
This organism has been subjected to so many investigations, its morphological and cultural characteristics are so well known, that one has little to add to its story. The characteristics of the B. pestis as met with in Hongkong are similar to those found in other parts of the plague world. It has been suggested to me by several professional gentlemen familiar with plague, that the type of micro-organism met with in Hongkong is in general smaller than that found in India and other countries. I have paid particular attention to this point, but fail to find the slightest difference. The measurement of bacteria in general is by no means fixed. One has only to examine the morphological records of different bacteria in order to convince one's self of the variations in measurement given by different authors. Again it must be remembered that the B. pestis is an organism which varies extensively in regard to its morphological appearances, and on this alone different measurements would be obtained at different times of examination. In short, I see no reason to believe that the plague bacillus as found in Hongkong differs in the slightest degree from that found in other parts of the world.
The most typical bacilli are obtained direct from the tissues of an animal suffer- ing from the disease. So far as my experience carries me, the bacilli are most frequently found isolated in the human body; in aminals, however, and particularly in the rat, the B. pestis tends to form short chains, the individual bacilli being markedly bipolar.
The various forms of plague bacilli met with in culture are similar to those already well known.
By the majority of observers, these various forms of the plague bacillus are regarded as Degeneration or Involution forms. That such is the case is by no means obvious, and until further research has been undertaken in regard to the involution forms of micro-organisms in general and the significance of these better known, it would be better to reseve one's opinion. So called involution or de- generation types of plague bacilli are by no means harmless. In fact, such forms we know to possess cousiderable virulence and are able to reproduce typical infections.
So far I have never observed branching forms of the B. pestis as describe:l by ALBRECHT and GHON, KOLLE and others. GorscHLICH's method of staining with dilute carbol-fuchsin has produced the most uniform result in staining. An excellent method of bringing out the bipolar appearance is that of GAFFKY's, namely, the treatment of the specimen with % acetic acid previous to the applica- tion of the stain.
By many obsevers, who have had considerable experience of plague, great weight has been laid upon the differential diagnostic significance of the polar staining of the B. pestis. To a certain extent, such a significance is justifiable, but