APPEARANCES OF CULTURES. 303 



line of growth, of finely nodose appearance. There is no 

 liquefaction of the medium, and no formation of gas. In 

 stroke cultures there is a thin bluish-white film, but it does 

 not spread to such an extent as in the case of the surface 

 growth of a stab culture (Fig. 79, B). In gelatine plates also 



FIG. 79 . 



A. Stab culture of the typhoid bacillus in gelatine, five days growth. 



B. Stroke culture of the typhoid bacillus on gelatine, six days' growth. 



C. Stab culture of the bacillus coli in gelatine, nine days' growth ; the gelatine is 

 split in its lower part owing to the formation of gas. 



the superficial and deep colonies present corresponding 

 differences. The former are delicate semi-transparent films, 

 with wavy margin, and are much larger than the colonies 

 in the substance, which appear as small round points. 

 These appearances, which are well seen on the third or 

 fourth day, resemble those seen in agar plates, as already 



