GENERAL CHARACTERS OF SPIROCILETES. 49 



in still-born foetuses, the offspring of syphilitic mothers, 

 is also urged as a strong argument in favour of 

 the infective character of the organism. The serum 

 of syphilitic subjects is said to agglutinate these 

 spirochaetes. 



While we may admit that a strong prima-facie case 

 can be made out for this view, it must be admitted that 

 there are still some objections to be overcome before 

 the Spiroch&ta pallida can be accepted as the proved 

 cause of syphilis. 



1. In the absence of cultures of the organism it can 

 only be identified by its morphological characters. 

 It is practically admitted that only those observers 

 who have made a prolonged study of this spirochaete 

 and of similar organisms can be sure of distinguishing 

 it from other forms. This condition of affairs some- 

 what vitiates the statistical method of proof, dependent 

 on the frequency of the finding of Sp. pallida in syphil- 

 itic lesions. 



On the other hand, this difficulty of identification 

 may be used as an argument by the up-holders of the 

 spirochaetal hypothesis against those who, like Kiolo- 

 menoglou and Cube, Krienitz and Scholtz, have found 

 spirochaetes which they identified as pallid in non- 

 syphilitic conditions. 



2. The question of the possible variability of form of 

 Sp. pallida has already been discussed (page 30) ; if 

 such variation be admitted, it becomes practically 

 impossible to be sure that it is only in syphilitic lesions 

 that this spirochaete is found, and its presence elsewhere 

 would of course be fatal to its causal connection with 

 syphilis. 



3 . Most observers have failed to find the spirochaete 

 in all the cases of syphilis which they examined. The 

 following figures may be quoted : 



