Bacilli Resembling the Diphtheria Bacillus 449 



mann's bacillus capable of neutralizing diphtheria antitoxin; he also 

 found that horses immunized with large qujantities of filtrates of the 

 Hofmann bacillus did not produceany antitoxin to diphtheria toxin. 



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

 ference 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. AUce Hamilton^ carefully studied 29 organ- 

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

 bacilU. 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, or- 

 ganisms 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 baciUus as a harmless saprophyte. Dr. Hamilton 

 believes it an important organism explaining some of the paradoxes 

 that we find at hand. Thus, cases of supposed diphtheria irremedi- 

 able by or deleteriously 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 without diphtheria, from the valves of whose 

 heart cultures of a diphtheria-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,l| who regarded it as the cause of xerosis conjunctivae, having 

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



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

 f'Jour. of Med. Research," 1904, xii (N. S., vol. vii), p. 475. 

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

 § "Jour. Infectious Diseases," vii, 1910, 335. 

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

 29 



