94 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



SOFT SORE 



A very strong case has been made out in favour of the view 

 that the bacillus described by Unna and by Ducrey is actually 

 the cause of soft sore, though the proof does not rest upon the 

 solid ground demanded by Koch. The bacillus has never been 

 cultivated outside the body, and the chief proof of its pathogenicity 

 rests upon the fact of its invariable presence in true soft sores. 

 It is hardly correct to say that it is invariably absent from other 

 sores, unless, indeed, we extend somewhat our conception of what 

 a soft sore really is ; for the author has found bacilli which were 

 indistinguishable from these in sores which were exactly like 

 those which follow herpes preputialis, though more severe than 

 is generally the case. But it is quite possible that future research 

 will show that the bacillus varies greatly in virulence, and that it 

 is only under certain circumstances that it produces typical soft 

 sores. At present all we can say about the diagnostic value of 

 the organism is that its presence in the secretion from an ulcer 

 affords strong evidence that the case is really one of chancroid, 

 and that its ab; ence almost certainly nullifies such a diagnosis. 

 It is scarcely necessary to say that syphilis and soft sore (or 

 gonorrhoea and soft sore) may be inoculated at the same time, 

 and the lesions appropriate to both diseases may be present 

 simultaneously. 



The bacillus in question is a short straight rod, less than a 

 quarter the length of the tubercle bacillus, and not much longer 

 than the bacillus of influenza. It is rather thick in proportion to 

 its length, its length being only about three times its breadth, and 

 it has rounded ends, which often stain more deeply than the 

 centre of the bacillus. It does not stain by Gram's method ; it 

 stains, indeed, with some difficulty, and powerful stains (such as 

 dilute carbol fuchsin or LofHer's blue) should be used. It is best 

 demonstrated in films made from the deeper parts of a typical 

 soft sore, for the superficial parts contain bacteria of all sorts, 

 and the recognition of Unna's bacillus is not easy unless it is 

 obtained in large numbers. 



The bacteriological examination for this bacillus has most often 

 to be made in cases of urethral sore, or of a sore concealed 

 beneath a phimosis. The method of obtaining the specimen is 

 the same in both cases. A fairly stiff platinum loop is inserted 



