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544 PATHOGENIC MICROORGANISMS 



Allow to dissolve and add 500 c.c. of 5 per cent carbolic acid in water. Let this 

 stand one or two days and filter. 



Stained by the method of Gram, the bacillus of Bordet and Gengou 

 is decolorized. 



Cultivation. Early attempts at cultivation made by the discov- 

 erers upon ordinary ascitic agar or blood agar were unsuccessful. They 

 finally obtained successful cultures from sputum by the use of the 

 following medium: 



One hundred grams of sliced potato are put into 200 c.c. of 4 per 

 cent glycerin in water. This is steamed in an autoclave and a glycerin 

 extract of potato obtained. To 50 c.c. of this extract 150 c.c. of 6-per- 

 cent salt solution and 5 grams of agar are added. The mixture is melted 

 in the autoclave and the fluid filled into test tubes, 2 to 3 c.c. each, and 



sterilized. To each tube, after sterilization, 

 is added an equal volume of sterile de- 

 fibrinated rabbit blood or preferably human 

 blood, the substances are mixed, and the 

 tubes slanted. 



On such a medium, inoculated with 

 sputum, taken preferably during the par- 

 oxysms of the first day of the disease, 

 colonies appear, which are barely visible 

 after twenty-four hours, 1 plainly visible 

 FIG. 116. BORDET-GENGOU after forty-eight hours. They are small, 

 BACILLUS. grayish, and rather thick. After the first 



generation the organisms grow with mark- 

 edly greater luxuriance and speed. On the potato-blood medium, 

 after several generations of artificial cultivation, they form a grayish 

 glistening layer which, after a few days, becomes heavy and thick, 

 almost resembling the growth of typhoid bacilli. In these later 

 generations, also, they develop readily upon plain blood agar or 

 ascitic agar and in ascitic broth or broth to which blood has been 

 added. In the fluid media they form a viscid sediment, but no pellicle. 

 Culturally, the 'bacillus varies from B. influenzae in growing less 

 readily on hemoglobin media than the latter, on first cultivation from the 

 sputum. Later it grows much more heavily on such media and shows 

 less dependence upon the presence of hemoglobin than does B. influenzse. 

 It also grows rather more slowly than the influenza bacillus. It is 



1 Wollstein, Jour. Exp. Med., xi, 1909. 



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