13 



Yersin's first published description was submitted to the French 

 Academy and reads as follows: 



The first bacteriologic researches were made on living subjects. An 

 examination of the blood drawn from the finger at various periods of the 

 disease failed to show the microbes, and the inoculations remained sterile. 

 The buboes, on the contrary, contained an abundance of a pure culture of 

 a very small, short bacillus, with rounded ends, which does not stain by 

 Gram's method, but does with Gentian violet. I have found this bacillus 

 in buboes of eight patients, and in two plague autopsies I have foimd the 

 same microbe. It is particularly numerous in the buboes, less abundant 

 in the other (lymphatic) ganglions, and very rare in the blood at the 

 moment of death. The liver and spleen are increased in size and contain 

 the specific bacillus. 



A short account of some animal experiments with post-mortem 

 findings forms the conclusion of Yersin's first report. The second 

 one gives an equally correct — in some respects more elaborate — 

 description of the bacillus, of its cultivation, and of animal experi- 

 ments. Kitasato, in his first description in the London Lancet 

 (August 25, 1894), states that the bacilli are to be found in the 

 blood, in the buboes, in the spleen, and in all the internal organs 

 of the victims of the disease. 



I am at present [he says] unable to say whether or not Gram's double- 

 staining method can be employed. The bacilli show very little movement. 



Metschnikoff's standpoint in the controversy as to the discovery 

 of the plague bacillus is perhaps the most correct and the most 

 impartial one, hence we quote his words in the language of the 

 original. He says : 



Yersin apres des recherches laborieuses eifectu6es dans des conditions 

 particulierement difficiles, decouvrit le microbe pesteux. Independamment 

 de lui Kitasato arrivait au meme resultat. Le savant japonais s'est born6 

 a communiquer quelques notes preliminaires sur ce sujet, tandis que Yersin 

 en a poursouvi I'etude avec perseverance; c'est done a lui que nous devons 

 le meilleur de nos connaissances actuelles sur la peste. 



MORPHOLOGY OF THE PLAGUE BACILLUS. 



The bacillus pestis is quite variable in its morphology, and it 

 is important to remember this fact in connection with the bac- 

 teriologic diagnosis of the disease. In post-mortem smears prepared 

 from a recent nonsuppurating primary bubo, from a pneumonic 

 focus, from the spleen, and occasionally from other internal organs 

 one generally finds numerous plague bacilli. In those from the 



