Specificity 487 



tally drew a living virulent culture of the diphtheria bacillus 

 through a pipet into my mouth. Through carelessness no 

 precautions were taken to prevent serious consequences, and 

 two days later my throat was filled with typical pseudo- 

 membrane which private and Health Board bacteriologic 

 examinations showed to contain pure cultures of the Klebs- 

 Loffler bacilli. 



Some have been led to doubt the specificity of the diphtheria 

 bacillus because of the existence of what is called the pseudo- 

 diphtheria bacillus. My conviction has always been that 

 this organism is but an attenuated or non- virulent diphtheria 

 bacillus, but it is commonly believed that the two organ- 

 isms are different, and until some one succeeds in transform- 

 ing one into the other, the matter must remain an opinion. 

 Bomstein* investigated the question and found that though 

 it was possible to modify the activity of virulent bacilli, and 

 bring back the virulence of non -virulent diphtheria bacilli, 

 it was impossible to make the pseudo-diphtheria bacillus 

 virulent. Denny f also found that the morphology of the 

 two organisms was continually different when they were 

 grown upon the same medium for the same length of time, 

 and that the short pseudo-diphtheria bacillus never showed 

 any tendency to develop into the large clubbed forms 

 characteristic of the true , diphtheria organism. The chief 

 points of difference between the bacilli are that the pseudo- 

 diphtheria bacillus, when grown upon blood-serum, is short 

 and stains uniformly; that cultures grown in bouillon 

 develop more rapidly at a temperature of from 2o-22 C. 

 than those of the true bacillus ; and that the pseudo-bacillus 

 is not pathogenic for animals. These distinctions are, 

 however, exactly what would be expected of an organism 

 whose virulence and vegetative powers had been altered, 

 by persistent manipulation or by unfavorable environment. 



Contagion. The diphtheria bacilli, being always present 

 in the throats of patients suffering from diphtheria, con- 

 stitute the element of contagion, and by being accidentally 

 discharged from the nose and mouth during coughing, 

 sneezing, vomiting, etc., endanger whoever comes in contact 

 with the patient. 



The results obtained by Biggs, Park, and Beebe in 'New 

 York are of great interest. Bacteriologic examinations 



*"Archiv Russes de Path.," etc., Aug. 31, 1902. 

 f American Public Health Association, 1902. 



