130 SPECIAL BACTERIOLOGY 



Motility. Non-motile. 



Staining Reactions. The bacilli stain readily in cover-glass speci- 

 mens with the ordinary basic aniline dyes (see Photomicrograph, Plate 

 III., Fig. 16). The staining is somewhat irregular, the bacilli presenting 

 a granular aspect owing to alternating clear and uncoloured spaces. 

 (For special staining methods, see Technique, 15.) They are not 

 stained by the Gram method. 



The bacilli are always present in diseased tissues, although great 

 difficulty is usually experienced in demonstrating them by staining 

 methods. When properly stained, they are found most numerous in the 

 centre of the nodules, becoming gradually less so towards the periphery . 

 Their usual position is between the cells, but sometimes they almost fill 

 some of the epithelial cells. They are always present in the nodules 

 (see Photomicrograph, Fig. 46), rarely in the blood, and if so, only in 

 small numbers. (For special methods of staining the bacilli in sections 

 of tissues, see Technique, 43, 44.) 



Spore Formation. It is still an open question if the glanders 

 bacillus forms spores or not. Some observers claim that spores are 

 present. The evidence of spore formation cannot be accepted when the 

 organism is subjected to the following tests : 



(1) The Bacillus mallei does not at any stage of its growth resist 



exposure to 3 per cent, carbolic acid solution longer than five 

 minutes, nor to 1 to 5000 corrosive sublimate solution for more 

 than five minutes. 



(2) It is destroyed in ten minutes in some experiments, and in five 



minutes in others, when exposed to a temperature of 55 C. 



(3) When dried, according to various authorities, it loses its vitality 



in from thirty to forty days. 



The conditions exhibited above are directly opposed to the existence 

 of spores. 



Biological Characters. The Bacillus mallei is a facultative 

 organism, growing both with and without oxygen. It develops on the 

 ordinary nutrient media. Minimum temperature, 25 C. ; optimum, 

 37 C. ; maximum, 42 C. The best growth is exhibited on 5 per cent, 

 glycerine agar medium. 



On Agar Media, with or without the addition of 5 per cent, glycerine, 

 it forms a moist, opaque, glazed layer, devoid of special characteristics. 

 Sometimes no growth occurs on ordinary agar. 



On Blood Serum it forms a moist, opaque layer of yellowish or dirty- 

 brownish drops. The serum is not liquefied. 



On Potatoes the Bacillus mallei exhibits a very characteristic growth, 

 which is somewhat rapid, and in twenty-four to thirty-six hours at 37 C. 

 a moist, amber-yellow, transparent deposit appears, becoming deeper in 



