PATHOGENIC BACTERIA. 277 



Sterile water. Inoculate on ordinary agar and on blood-agar. 

 The influenza bacillus should grow only on the blood-agar and 

 have the other characters above mentioned. Any organism 

 that grows on both the ordinary and the blood-agar must be 

 rejected. As far as is known, this organism attacks spon- 

 taneously only human beings. It probably does not grow 

 outside the body in nature. In cases of influenza" it is found in 

 the mucous discharges and in the bronchi and lungs. It is 

 the predominating organism in some cases of bronchitis.* 

 According to Canon, the bacilU may sometimes be found in the 

 blood. 



Bacillus diphtheriae (Klebs-Loffler). — ^A straight or 

 sHghtly curved bacillus, usually 1.2 to 2.5 /i in length, with 

 rounded or shghtly pointed ends, remarkable for showing 

 irregularities of form, sometimes being club-shaped or spindle- 

 shaped; branching forms have been found.f It is not motile 

 and does not form spores. It retains the stain after Gram's 

 method, but it is best stained with watery solutions of the 

 anihne dyes, especially Loffler's alkaHne methylene-blue. 

 Very characteristic pictures are obtained by the method of 

 Neisser: 



Solution No. 1. 



Methylene-blue i 



Alcohol (96 per cent.) 20 



Distilled water 950 



Glacial acetic acid S° 



Solution No. ;:. 



Bismarck brown i 



Boiling distilled water S°° 



Stain the cover-glass preparation which has been fixed 

 in the flame in No. i one to three seconds; wash in water; 

 stain in No. 2 three to five seconds; wash in water; mount 



* See Lord. Boston Medical and Surgical Journal. December 8, 1902. 

 tHill. Journal Medical Research. Vol. VII. 1902. 



