Experimental Infection 633 



Sero-sanguinolent effusions may * occur into the serous 

 cavities. 



Devell * has found frogs susceptible to the disease. 



Wyssokowitsch and Zabolotny f found monkeys highly 

 susceptible to plague, especially when subcutaneously in- 

 oculated. When an inoculation was made with a pin dipped 

 in a culture of the bacillus, the puncture being made in the 

 palm of the hand or sole of the foot, the monkeys always 

 died in from three to seven days. In these cases the local 

 edema observed by Yersin did not occur. They point out 

 the interest attaching to infection through so insignificant a 

 wound and without local lesions. 



Klein } found that intraperitoneal injection of the bacillus 

 into guinea-pigs was of diagnostic value, producing a thick, 

 cloudy, peritoneal exudate rich in leukocytes and containing 

 characteristic chains of the plague bacillus occurring in 

 twenty-four to forty-eight hours. 



Animals fed upon cultures of the bacillus or upon the flesh 

 of animals dead of the disease became ill and died with typi- 

 cal symptoms. When Klein inoculated animals with the 

 dust of dwelling-houses in which the disease had occurred, 

 some of them died of tetanus, one from plague. Many rats 

 and mice died spontaneously in Hongkong, examination 

 showing the characteristic bacilli. 



Yersin showed that flies may die of the disease. Macer- 

 ating and crushing a fly in bouillon, he not only succeeded 

 in obtaining the bacillus, but infected an animal with it. 



Nuttall, in repeating Yersin 's fly experiment, found his 

 observation correct, and showed that flies fed with the cad- 

 avers of plague-infected mice die in a variable length of time. 

 Large numbers of plague bacilli were found in their intes- 

 tines. He also found that bedbugs allowed to prey upon 

 infected animals took up large numbers of the plague bacilli 

 and retained them for a number of days. These bugs did 

 not, however, infect healthy animals when allowed to bite 

 them ; but Nuttall was not satisfied that the number of his 

 experiments upon this point was great enough to prove that 

 plague cannot be spread by the bites of suctorial insects. 



* "Centralbl. f. Bakt. u. Parasitenk.," Oct. 12, 1897. 

 f'Ann. del'Inst. Pasteur," Aug. 25, 1897, xi, 8, p. 665. 

 t "Centralbl. f. Bakt. u. Parasitenk.," xxi, No. 24, July 10, 1897, 

 p. 849. 



Ibid., Aug. 13, 1897. 



