BACTERIA IN INFECTIOUS DISEASES. 577 



round ends. It was readily stained with a solution of fuchsin, but 

 not by Gram's method. 



Unna, in 1892, reported that in five cases of chancroid he had 

 found a strepto-bacillus, which on account of its numbers and situa- 

 tion in the tissues involved would probably prove to be the specific 

 cause of this localized infection. Quinquaud (1892) confirmed Unna 

 as to the presence of a strepto-bacillus, but neither of the bacteriolo- 

 gists named succeeded in obtaining this bacillus in cultures. Since 

 this date numerous papers have been published with reference to the 

 presence of this and other bacilli in chancroidal ulcers. In his latest 

 communication (1895) Unna maintains that the bacillus of Ducrey 

 is in fact identical with his strepto-bacillus. He says that the pres- 

 ence of this bacillus has now been demonstrated in more than one 

 hundred cases; and, on the other hand, it has never been found in 

 pus from other sources. It is readily stained by Gram's method, and 

 this serves to distinguish it from the only similar strepto-bacillus 

 which is often found in serpinginous chancroid and especially about 

 the margins. Unna asserts that this strepto-bacillus is constantly 

 present, that it is the only microorganism in the chancroidal tissue, 

 and that it has not been found elsewhere. He therefore feels justified 

 in concluding that it is the specific etiological agent, although it has 

 not as yet been obtained in pure cultures. 



Spietschka (1894) also reports the presence of strepto-bacilli in 

 chancroidal ulcers, and says that the bacilli seen by him correspond 

 with those found by Unna and later by Peterson, as to size, arrange- 

 ment, and location, but that they have rounded ends and a constric- 

 tion in the middle and do not stain by Gram's method i.e., they 

 correspond with the bacillus described by Ducrey. Peterson (1894) 

 has also found the bacillus of Ducrey in his cases, in St. Petersburg, 

 and thinks there can be no doubt that it is the specific etiological 

 agent. Krefting has never failed to find this bacillus in chancroidal 

 virus, and in inoculations made with such virus the quicker and 

 more intense the result the more numerous were the bacilli found to be. 



For the staining of cover-glass preparations Krefting recommends 

 the methylene blue solution of Sahli : Aqua destillata, 40 cubic centi- 

 metres; saturated aqueous solution of methylene blue, 24 cubic centi- 

 metres; solution of borax (five per cent) 16 cubic centimetres. Ac- 

 cording to Krefting the bacilli are from 1.5 to 2 v- long, and from 0.5 

 to 1 /j. broad. Ducrey describes his bacilli as short, thick rods, with 

 round ends, and at times a slight constriction in the middle. Unna 

 describes his bacilli as short rods, l to 2 v- long and /* broad, ar- 

 ranged in chains of four to ten elements. These chains are con- 

 stantly ' found in the lymph spaces, between the cells never in the 

 leucocytes or blood-vessels. 



