SYPHILIS. 383 



and it is evident that the greatest caution must be 

 exercised in drawing any conclusions as to their 

 etiological import. For there is nothing improbable 

 in the supposition that tissues of a low grade of 

 vitality may be invaded by parasites which have 

 no causal relation to the morbid process; and in 

 view of what we know of the extended distribu- 



Fig. 21. 

 Soft chancre secretion with bacteria, magnified 850 diameters. (Drawn by Heitzmann.) 



tion and infinite variety of organisms of this class, 

 their absence from the secretions of an open ulcer 

 would be more remarkable than their presence. 

 In a second communication, dated March 23, Dr. 

 Morison states that a modification of his method 

 of staining has enabled him to demonstrate that 

 the rods seen in Fig. 20 are really formed of 

 closely united cocci, corresponding with those de- 

 scribed by Birch-Hirschfeld. He further says : 



