316 BACTERIOLOGY. 



that are present. Also, in this event, the streptococci 

 retain the Gram stain, while the pest bacilli do not and 

 the staphylococci may or may not. It has been sug- 

 gested that possibly the organisms found by Kitasato 

 in the blood, and which he describes as pest bacilli, 

 that retained the color when treated by the method of 

 Gram, were pairs of micrococci, and not bacilli at all. 



It is the opinion of Aoyama that the suppuration of 

 the glands is not caused by the plague bacillus, but is 

 rather the result of the action of the pyogenic cocci 

 with which it is so often associated. It is also his 

 belief that the most important and frequent mode of 

 infection in man is through wounds of the skin. He 

 does not regard either the air-passages or the alimentary 

 tract as frequent portals of infection. Wilm, on the 

 contrary, is inclined to regard the alimentary tract as a 

 frequent portal of infection; 2 and subsequent investiga- 

 tions leave little doubt that infection occasionally occurs 

 through the respiratory tract. 



The order in which the lymphatics manifest disease 

 appears to depend upon the location of the primary 

 infection. That is to say, if it is upon the feet, as of 

 persons who go barefooted, the superficial and deep 

 inguinal glands are the first to show signs of the dis- 

 ease ; while if infection occurs through wounds of the 

 hand, the buboes appear first in the axillary region. 

 As a rule, the wound through which infection is re- 

 ceived shows little or no inflammatory reaction. 2 



i Wilm: loc. cit. 



2'fhe works of Yersin, of Kitasato, and of Aoyama have been ex- 

 haustively reviewed by Flexner in the Bulletin of the Johns Hopkins 

 Hospital, 1894, vol. v. p. 96, and 1890, vol. vii. p. 180. I am indebted to 

 these reviews for much that is here presented on this subject. 



