Beport on the Bacteriology of Water. 



287 



widening "stem," which is filled with the liquid. The peculiar 

 green fluorescence is very marked in these cases, masking somewhat 

 the true colour of the colony itself. 



On agar the colonies rapidly spread at 20 — 25° C. (more slowly at 

 12 — 15° C), as a thin, wet-looking, or almost waxy, greenish-white 

 layer, becoming thicker eventually, and very smooth and glassy, and 

 tinging the subjacent agar with the characteristic hue. Here and 

 there longer rods can be found in agar cultures, but no trace of spore 

 formation could be discovered either on this or any other medium. 



On potato the colonies are brownish-yellow, becoming deeper with 

 age, and often with a raised, rough, granular surface, moist or oily in 

 appearance. On all the solid media the fact that" this bacillus is 

 strictly aerobic comes out very strongly. Its growth is at once in- 

 hibited if a sterilised glass cover slip is placed over the young colony : 

 the liquid rapidly fills up all the interspaces, and no air can enter, 

 and growth stops at once. Moreover, if a " stab " culture is carefully 

 made and covered with gelatine, the same inhibition is noticed. 



The marked and rapid disappearance of this form from water 

 which is kept standing in a closed vessel is almost certainly to be 

 attributed to the same cause. 



We have made numerous attempts to cultivate this form in hang- 

 ing drops of gelatine, and with success, but there are no special 

 points to notice : the rods divide very rapidly, and never grow out into 

 long filaments or form spores in the moist chambers. It is impossible 

 to cultivate it under a cover slip in compressed gelatine. 



Milk is rendered slightly acid by the bacillus, and coagulation and 

 peptonisation follow. 



The slimy, green, fluorescent liquid presents several interesting 

 features. Slight quantities of acid — hydrochloric or acetic — cause 

 the green colour to disappear ; but neutralisation with ammonia at 

 once restores it, and an excess of the alkali deepens the hue. The 

 colour is not destroyed by boiling, though, if prolonged, the green 

 hue becomes distinctly paler. This agrees exactly with Mace's 

 account of it, and is no doubt strong confirmatory evidence as to the 

 correctness of our identification of the Schizomycete. 



The annexed table summarises the character of this Schizomycete. 



