BACILLUS PERTUSSIS 421 



Isolation and Culture. Unlike the influenza bacillus, B. pertussis 

 can be made to grow in media which do not contain hemoglobin. For 

 initial growths outside of the human body, however, Bordet and 

 Gengou have recommended a potato-glycerin-blood agar medium 

 which is claimed to be far more efficient than blood agar. 1 The Bor- 

 det-Gengou bacillus is more readily isolated from the bronchial secre- 

 tion during the first paroxysms 2 than later in the disease. Cultures 

 are obtained from bronchial mucus which has been washed several 

 times in sterile water, then spread on the surface of the potato medium 

 and incubated at 37 C. After twenty-four to forty-eight hours' 

 incubation colonies appear as very minute, transparent growths 

 which resemble dew drops; colonies of B. influenzse frequently develop 

 at the same time, but the colonies of the latter are somewhat larger 

 than those of B. pertussis. Secondary transplantations of B. pertussis 

 upon fresh potato-glycerin-blood agar grow more luxuriantly than 

 of B. influenzae, however, and after repeated transfers the Bordet- 

 Gengou bacillus will grow upon ascitic agar. The influenza bacillus 

 will not grow in media free from hemoglobin. Ordinary media, unless 

 ascitic fluid or blood serum is added, are wholly unsuited for the 

 growth of B. pertussis. 



B. pertussis, like the influenza bacillus, is an aerobic organism. 

 Anaerobic development has not been obtained. The optimum tem- 

 perature of growth is 37 C.; Wollstein 3 states that slight development 

 takes place even at 5 to 10 C. An exposure of thirty minutes at 

 57 to 60 C. prevents further development in artificial media. The 

 organisms may remain viable upon the potato-glycerin-agar medium 

 for two months. 



Products of Growth. According to Wollstein, 4 no acid is produced 

 in dextrose, lactose, saccharose or mannite serum broth. No enzymes 

 have been demonstrated in cultures of the organism, and it produces 

 no visible changes in hemoglobin. Extracellular toxins have never 

 been demonstrated, but autolyzed cultures introduced intravenously 



1 It is prepared as follows: 100 grams finely chopped potatoes are boiled in 200 c.c. 

 of 4 per cent, glycerin for a short time, then cooled. To every 100 c.c. of the potato 

 glycerin extract there is added 300 c.c. of 7.5 per cent, agar containing 0.5 per cent. 

 NaCl. The glycerin potato extract replaces the usual peptone-meat-juice nutrients of 

 nutrient agar. The mixture is heated to boiling, filtered, and sterilized in test-tubes 

 about 3 c.c. of medium per tube. (Old potatoes which are slightly alkaline in reaction 

 are much better than new potatoes which are usually acid in reaction, in preparing the 

 glycerin extract.) To each tube of the sterilized glycerin potato agar medium is added 

 an equal volume of sterile, defibrinated human or rabbit's blood, while the medium is 

 still warm, 45 to 50 C. Then the mixture is cooled in an inclined position. 



2 Wollstein, Jour. Exp. Med., 1909, xi, 41. 



3 Loc. cit. Loc. cit. 



