316 CLINICAL BACTERIOLOGY. 



On examination of syphilitic papules he found the bacilli between 

 the prickle-cells of the rete Malpighii. The bacilli are from 3.5 

 to 4. 5 fi long and about i /* thick, straight or bent, in part irregu- 

 larly curved, and their surface presents a wavy contour. They 

 are found constantly in the syphilitic lesions in varying number, 

 but, on the whole, not abundantly. 



A number of observers have confirmed Lustgarten's state- 

 ments, while others have failed to find his bacilli. The signifi- 

 cance of Lustgarten's observations was severely shaken when 

 Matterstock and Alvarez and Tavel found bacilli in smegma 

 that could be stained by the method of Lustgarten, and that 

 also closely resembled the bacilli of syphilis morphologically. 

 Doutrelepont maintained, subsequently, that after staining for 

 forty-eight hours in aqueous methyl-violet solution, and decolori- 

 zation with solution of ferric chlorid and alcohol, the smegma- 

 bacilli yielded up their color, whereas the Lustgarten bacilli 

 retained theirs. Nevertheless, the opinion is quite generally 

 held that the so-called bacilli of syphilis are identical with the 

 smegma-bacilli, of which not a few take the stain characteristic 

 for tubercle-bacilli. This circumstance must, further, be borne 

 in mind in examinations for genito-urinary tuberculosis. Con- 

 fusion between tubercle-bacilli and smegma-bacilli may be 

 avoided by a knowledge of the fact that the latter exhibit less 

 resistance to the action of hydrochloric acid and nitric acid than 

 the former. The smegma-bacilli exhibit still less resistance to 

 the action of alcohol. 



The bacillus of Lustgarten can not, therefore, be consid- 

 ered as the exciting agent of syphilis, although it may 

 possibly bear some relation to this disease. Whether bac- 

 teria are the cause of syphilis at all is wholly doubtful. 

 A bacterial etiology for syphilis is generally assumed be- 

 cause of the varied resemblance of its clinical manifesta- 

 tions to those of other bacterial infectious diseases as, for 

 instance, tuberculosis and leprosy. Perhaps, however, the 

 exciting agent of syphilis is of an entirely different nature. 

 It is only certain that it is an organized body, a contagium 

 vivum, but nothing further is at present known with regard 

 to it. Investigation in this field is attended with great 

 difficulties because syphilis is not transmissible to animals, 

 and experimentation fails. According to some observers, 

 monkeys are said to be capable of acquiring syphilis, 

 while others deny this assertion. At least, it appears 

 that not all varieties of monkeys are susceptible to the 

 disease. 



