322 BACTERIOLOGY. 



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. 1 



\Vyssokowitz and Zabolotny 2 call attention to the 

 fact that the blood of patients convalescing from plague 

 has an agglutinating action upon fluid cultures of the 

 plague bacillus analogous to that observed when the 

 blood-serum of typhoid or of cholera patients is mixed 

 with similar cultures of the typhoid or the cholera 

 bacillus. 



Yersin, Calmette, and Borrel 3 have demonstrated that 

 the general principles underlying the establishment of 

 artificial immunity apply as well to this disease as to 

 a number of others. They have shown that by the use 

 of dead cultures (destroyed by heat) of the plague 

 bacillus animals may be rendered immune from infec- 

 tion by the virulent living organism. They have also 

 shown that the serum of the blood of these animals is 

 not only capable of conferring immunity upon other ani- 

 mals into which it is injected, but it has curative proper- 



1 The works of Yersin, of Kitasato, aud of Aoyama have been ex- 

 haustively reviewed by Flexner in the Bulletin of the Johns Hopkins 

 Hospital, 1894, vol. v. p. 96, and 1896, vol. vii. p. 180. I am indebted 

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



1 Annales de 1'Institut Pasteur, 1897, p. 663. 



5 Ibid., 1895, p. 589. 



