194 N. S. FERRY AND ARLYLE NOBLE 



At first the experiments were undertaken with two strains of 

 Bad. pertussis which had been cultured since 1911, one having 

 been furnished by the laboratory of Bordet and the other iso- 

 lated in our own laboratory, and three strains of B. hronchi- 

 septicus isolated by one of us (N. S. F.), one from a dog in 1908, 

 one from a monkey in 1912 and one from a human subject in 1913. 

 Later on these strains were augmented by ten strains of Bact. 

 pertussis, furnished by Dr. Olga R. Povitzky of the New York 

 Board of Health Laboratory, through the courtesy of Dr. Park, 

 and three strains of Bact. influenzae, together with one strain of a 

 Bact. pertussis-hke organism from pertussis sputum, isolated in 

 our own laboratory. 



CULTURAL REACTIONS 



When first isolated, the Bact. pertussis developes slowly and, 

 as a rule, preferably on special media, as reported by Bordet, 

 Woolstein and others. After several months of repeated trans- 

 plantings, however, its ability to grow on various media gradu- 

 ally increases until it finally presents a growth almost identical 

 to, and nearly as luxuriant as, that of B. bronchisepiicus, and by 

 that time can be cultured on ordinary media. 



It has been found by the writers that the one great difference 

 between the two organisms lies in their power of locomotion; 

 the B. hronchisepticus is motile while the Bact. pertussis is non- 

 motile, several months of attempting to develop a strain that 

 would give some evidence of motility resulting in failure. 



While the cultural reactions have been found practically 

 identical, even to the alkali production in litmus milk, contrary 

 to the report of Mallory, and the tan color on potato is shared by 

 both, yet, with the Bact. pertussis, these reactions are extremely 

 tardy in making their appearance, usually taking about two or 

 three weeks longer than with the B. hronchisepticus. At the 

 end of this time, however, it is practically impossible to differ- 

 entiate between the cultures of the two organisms. 



The following outline will show the characteristics of these 

 organisms, in a general way: 



