486 WHOOPING-COUGH 



an account of another minute organism, and brought forward 

 certain facts which gave strong support to its etiological re- 

 lationship. A short description of this bacillus may accordingly 

 be given. 



Characters of the Bacillus (Bordet-Gengou). The organism, 

 as seen, for example, in the sputum, occurs in the form of 

 minute oval rods scarcely larger than the influenza bacillus. 

 They stain rather faintly with ordinary stains, and their margin 

 and extremities are often more deeply coloured than the centre, 

 which may appear as an uncoloured spot; they are Gram- 

 negative and do not 

 form spores. In cul- 

 tures they present the 

 same characters and are 

 less pleomorphous than 

 the influenza bacillus 

 (Fig. 144). They are 

 specially numerous at 



sputum expec- 

 torated from the 

 bronchi; as the disease 



advances they become 

 FIG. 144. 1 Film preparation from a twenty- i -,- 



four hours' culture of the bacillus of whoop- scantv > and ma y dlsa P' 

 ing-cough. (Bordet-Gengou). pear when the symptoms 



Stained with carbol-fuchsin. xlOOO. o f the disease are still 



prominent. The bacillus 



has not been found in the blood, unless as an agonal pheno- 

 menon (Klimenko). Bordet and Gengou succeeded in obtaining 

 pure cultures on the blood-agar medium described on p. 44, 

 and this was found to be the most suitable of all the media 

 tried. In the first cultures growth is very scanty and may 

 be invisible, but later it becomes much more abundant, and 

 sub-cultures may also be readily made on ordinary serum-agar 

 media. As compared with that of the influenza bacillus, growth 

 is thicker and less transparent and the margins are more sharply 

 marked off; the presence of haemoglobin, though favouring the 

 growth, is not so essential as in the case of the latter organism. 



1 We are indebted to Dr. Bordet for the culture from which this preparation 

 was made. 



