344 MANUAL OF BACTERIOLOGY. 



organism so called it merely a more or less modified form of the 

 diphtheria bacillus. 



At a meeting of the Association of American Pathologists and Bacteriol- 

 ogists, Perkins* described two organisms, or one organism with variations of 

 characteristics, which he came across in routine examinations of cultures from 

 throats of persons suspected of having diphtheria, and which he regards as 

 likely to lead to error. The points of difference from the diphtheria which 

 are given below would seem, however, to make a differentiation not very difficult 

 with proper care. Although resembling the bacillus of diphtheria bacillus, it 

 differs in having a greater regularity in outline than the latter, and in fa'ct that 

 this regularity persists after treatment with acetic acid. The chromophylic 

 granules take a deeper stain than in the diphtheria bacillus. The organism 

 is motile and forms spores. In old cultures there is distinct thread formation, 

 with true, but inconstant branching in cultures over a month old. Gelatine is 

 slowly Uquefied. To guard against error it would seem necessary for those 

 who make routine examinations for diphtheria merely to test the organisms 

 which resemble diphtheria bacilli for motility in order to avoid, the possibility 

 of mistaking this organism of Perkins for the genuine diphtheria bacillus. 

 The formation of spores after twenty-four hours would also enable one to 

 distinguish the Perkins organism from the true diphtheria bacillus. 



Persons who harbor the diphtheria bacilli in their throats 

 whether they show any clinical symptoms or no should be re- 

 garded as a menace to those around. Their throats should be 

 actively treated with suitable antiseptics and water, and fre- 

 quently examined for the presence of the organism. It is 

 probable that in this way such persons can be quickly rendered 

 harmless to those about them. 



The diphtheria bacillus is pathogenic for guinea-pigs, rabbits, 

 cats, chickens, pigeons and to a somewhat lesser extent, for 

 dogs, goats, cattle and horses.f When it is injected into them 

 it produces a toxemia. In the guinea-pig, which is especially 

 susceptible, local inflammation results, and death occurs 

 usually in two or three days. The bacilli are found to be con- 

 fined to the vicinity of the wound, and not usually to be'dis- 



*Personal communication to Dr. Williams. 



fPark. Pathogenic Bacteria and Protozoa. New York and Philadelphia. 

 1905. p. 192. 



