272 BACTERIOLOGY. 



spores, were observed around wounds in gangre- 

 nous septicaemia, and considered to be the cause 

 of the gangrene. 



. Bacillus tuberculosis, Koch.* Rods, 2 4 p 

 and occasionally 8 p long, very thin, and rounded 

 at the ends. They are straight or curved, and 

 frequently beaded (Fig. 104), and occur singly, in 

 pairs, or in bundles. They are found in the cells 



FIG. 104. BACILLUS TUBERCULOSIS, FROM TUBERCULAR SPUTUM, STAINED 

 BY EHRLICH'S METHOD, x 2500. From photographs. 



of tubercles, especially in the interior of giant 

 cells. In the latter they are often accompanied 

 with grains which exhibit the same colour reaction 

 (Plate XVIII. , Fig. i). They are non-motile. 

 Spore-formation has been described (see p. 134). 

 The best medium for cultivation is solid blood 

 serum of cow or sheep, with or without the 

 addition of gelatine ; and the most favourable tem- 

 perature for their development is 37 38 C. The 



* Koch, Berl. Klin. Woch., No. 15, 1882 ; and MittheiL aus dem 

 KaiserJich. Gesundheitsamte> " ^Etiologie der Tuberkulose." 



