NUTRIENT JELLY IN TEST-TUBES. 



8i 



organisms inoculated in the antiseptic vapour do not there- 

 by lose their vitality, while, if the spray be an efficient one, all 



Fig. 35. Fig. 36. 



Fig. 35. — Growth of violet bacillus in nutrient jelly. The growth 

 commences first near the surface, along the track of the needle. 

 Liquefaction rapidly takes place, the liquefied material forming a 

 kind of inverted cone, the apex of which is made up of small beads 

 or globes, in which the violet masses of bacillus are deposited. 



There is a violet scum floating on the surface of the slightly turbid 

 liquid ; if the test-tube be shaken slightly, part of this sinks. Near 

 the apex of the cone, and on the floor of the small beads, masses of 

 the violet bacillus are seen. 



Fig. 36. — Fluorescing bacillus growing in nutrient jelly. A 

 delicate green, slightly opalescent, film is seen on the surface of the 

 jelly. A pale grey growth is seen along the track of the needle. The 

 surrounding jelly gradually assumes a peculiar green fluorescent ap- 

 pearance, which alters very considerably according to the back- 

 ground and the lighting used. This resembles the bacillus of blue 

 milk in many respects, especially below the surface. The surface 

 growths, however, differ very materially. 



F 



