Bacilli Resembling the Diphtheria Bacillus 431 



Hof mann bacillus did not produce any antitoxin to diphtheria toxin. 

 Eleven different cultures were studied and the results are very 

 important. 



Cobbett* and Knappf show that there is a chemicobiologic differ- 

 ence between the true and pseudo-diphtheria bacilli, in that the 

 latter does not ferment dextrin or any of the sugars as the true 

 bacillus does. 



Chemistry. The chemical peculiarities of the culture serve to 

 make certain that Bacillus hofmanni is an independent micro-or- 

 ganism. Under no circumstances does it produce or can it be made 

 to produce toxin. Under no circumstances can it be made to produce 

 acid through the decomposition of sugars. 



Pathogenesis. Dr. Alice HamiltonJ carefully studied 29 organ- 

 isms, of which 26 corresponded fully with the pseudo-diphtheria 

 bacilli. They were divisible into three groups : I, Those non-patho- 

 genic for guinea-pigs; II, those that produce general bacteremia in 

 guinea-pigs, and are neutralized by treatment with the serum of a 

 rabbit immunized against a member of the group; III, organisms 

 which form gas in glucose media, produce bacteremia in guinea-pigs, 

 and are neutralized neither by diphtheria nor by pseudo-diphtheria 

 antitoxin. Some of the organisms of the second group are also 

 pathogenic for man. Instead of regarding the pseudo-diphtheria 

 bacillus as a harmless saprophyte, Dr. Hamilton believes it an im- 

 portant organism explaining some of the paradoxes that we find at 

 hand. Thus, cases of supposed diphtheria irremediable by or dele- 

 teriously affected by antitoxic serum may depend upon one of these 

 organisms. It is also probably one of them that Councilman found 

 in his case of "general infection by Bacillus diphtheriae," and that 

 Howard encountered in his case of acute ulcerative endocarditis with- 

 out diphtheria, from the valves of whose heart cultures of a diph- 

 theria-like organism not pathogenic for guinea-pigs was isolated. 



The still more recent and comprehensive work of Clark shows that 

 no kind of manipulation is capable of so modifying Bacillus hofmanni 

 as to make its identity with B. diphtheriae in the least likely. Clark 

 is, however, willing to admit the probability that the organisms may 

 .have descended from a common stock. 



BACILLUS XEROSIS 



This bacillus was first described in 1884 by Kutschbert and 

 Neisser,|| who regarded it as the cause of xerosis conjunctivae, having 

 found it upon the conjunctiva in that disease. It has, however, been 

 so frequently found upon the normal conjunctiva that it can no 

 longer be looked upon as pathogenic. It is also found upon other 

 * 'Centralbl. f. Bakt. u. Parasitenk.," 1898, xxm, 395. 



'Jour, of Med. Research," 1904, xn (N. S., vol. vn), p. 475 

 'Jour. Infectious Diseases," 1904, i, p. 690. 

 'Journal of Infectious Diseases," vn, 1910, 335. 

 'Deutsche med. Wochenschrift," 1884, Nos. 21, 24. 



