2-i Proceedings of the Royal. Irish Academji. 



second day liquefaction proceeds rather rapidly, circnlar depressions being 

 formed filled with liquefied gelatine of a greyish tinge if the bacteria are uni- 

 formly distributed through it. If, as is frequently the ease, the distribution 

 is less uniform, a greyish white, inregularly shaped deposit is found in the 

 depression. In ordinary beef-extract-peptone gelatine the appearances are 

 sunilar ; but the rate of liquefaction is slightly less rapid. In no case is 

 there the slightest trace of any green fluorescence. The liquefied gelatine is 

 strongly alkaline to litmus, and when a moistened red litmus paper is attached 

 to the inside of the lid of a Petri-dish containing colonies of the organism and 

 the hd replaced, the htmus is quickly turned blue, indicating the presence of 

 a volatile alkali There is, however, no smell of ammonia. 



(7) Gelatine Siah. — ^After twenty-foui- hours at room temperature a more or 

 less continuous line of growth along the stab is visible, usually extending to 

 the bottom of the tube. By the second day liquefaction has started at the 

 surface, and proceeds downwards at a fairly rapid pace, the liquefied portion 

 being somewhat elongated, broadly funnel-shaped, liquefaction being sti'ongest 

 in the uppermost layers near the aii\ The aeeiunulated bacterial gi'owth 

 forms more or less flocculent masses which gradually settle downwards. 



(8) Gelatine Streak. — ^After twenty-four hours the streak is visible, by 

 meajis of a lens, in the form of a fine discontinuous line of a whitish grey 

 colour. Liquefaction sets in within forty-eight hour's, the margin of the 

 liquefied portion being of an irregular nature, and spreading rather rapidly. 



(9) Agar Plates. — The colonies on beef-exti-act-peptone agar appear after 

 forty-eight houi-s at 25' C. as small whitish dots when submei^ed, similar to 

 those in gelatine. On the sm-face the colonies are larger, dull grey, with 

 sometimes a white centre. Owing to the exudation of water fi-om this mediiim, 

 the surface colonies soon become merged into a general surface growth over the 

 plate so that their individual ehai-acters become lost. 



(10) Agar Stab. — ^At laboi-atory temperature after twenty-foui* hours a 

 gi-eyish white, faint line of growth is seen along the stab, which at this time 

 does not usually reach the bottom of the tube. By the thii-d day the surface 

 of agar in the tube is covered by a greyish white gi'owth. The line of growth 

 meanwhile has reached the bottom of the tube, the margin of it being some- 

 what crenated. 



(11) Agar Streak.— At 2T C. to 25° C. a slight greyish white growth 

 develops within forty-eight hours, which quickly spreads over the sui-face, aided 

 by exuded water. 



(12) Ordinary Broth. — In beef-extract-peptone broth, growth is by no 

 means vigorous. Within forty-eight hours at laboratory temperature the 

 amount of turbidity in the Hquid is but shght : and even after standing for a 



