412 THE HEMORRHAGIC SEPTICEMIA GROUP 



appear yellowish in contrast to the hemorrhagic points. A simple 

 inspection suffices as a rule to establish a correct diagnosis, although 

 cultures and smears should be prepared. Occasionally rats are sub- 

 mitted for diagnosis which are badly decomposed. The rapid over- 

 growth of adventitious bacteria makes the isolation of Bacillus pestis 

 difficult by ordinary methods. Albrecht and Ghon 1 have shown that 

 the plague bacillus, even in the presence of large numbers of con- 

 taminating bacteria, may be obtained in pure culture by rubbing the 

 suspected material upon the freshly shaved abdomen of a guinea- 

 pig. The plague bacillus readily penetrates the skin and causes a 

 rapidly fatal generalized infection with characteristic lesions. It may 

 be obtained in pure culture from the internal organs. Fritsche 2 has 

 found that other bacteria, even of the hemorrhagic septicemia group, 

 fail to penetrate the skin and infect the animal. This cutaneous test 

 is of great diagnostic importance. 



McCoy and Chapin 3 have described a disease superficially resem- 

 bling plague in its pathological anatomy caused by Bacillus tularense. 

 The disease is readily transmitted to guinea-pigs, rabbits and mice, 

 less readily to rats. Wherry and Lamb 4 have recently isolated the 

 organism from an epizootic among wild rabbits and from a human 

 case presenting corneal ulcerations and lymphadenitis. 



Man. The atria of infection are chiefly the skin and the respira- 

 tory tract, giving rise to two general types of the disease, glandular 

 and pneumonic plague. Rarely a localized cutaneous lesion, plague 

 carbuncle, is met with where the focus of localization of the organisms 

 appears to be very circumscribed. Cases of pneumonic plague which 

 develop sporadically during epidemics of the bubonic type do not as 

 a rule appear to spread rapidly; on the contrary, during epidemics 

 in which the pneumonic type predominates the infectivity from man 

 to man is very great. No theory has been presented in explanation 

 of this very unusual phenomenon, and the origin of the pneumonic type 

 of the disease is not definitely known. 5 Typical pneumonic plague 

 resembles lobar pneumonia in its symptomatology, and the fatalities 



1 Denkschrift der math-Naturw. Klasse der kaiserl. Akad. d. Wissensch., Wicn., 

 1898, Ixvi. 



2 Arb. a. d. kais. Gesamte, 1902, vol. xviii. 



3 Jour. Inf. Dis., 1912, x, 61; Public Health Bull., April, 1911, No. 43; ibid., January, 

 1912, 53. 



4 Jour. Inf. Dis., 1913, xv, 331 ; Jour. Am. Med. Assn., 1914, Ixiii, 2041. 



6 Animal experiments suggest that attenuated cultures of Bacillus pestis which fail 

 to kill guinea-pigs by subcutaneous inoculation may give rise to a fatal infection when 

 inoculated into the respiratory tract, and that the virulence of cultures may be recovered 

 by this process. The high mortality observed during epidemics of pneumonic plague 

 in man may be a similar phenomenon. 



