26 Proceedings of the Royal Irish Academy. 



(23) Sterilized Skim-Milk. — At 25° C. curdling occurs within forty-eight 

 hours ; at laboratory temperature in five days. The curd does not form a very 

 firm compact column. The milk, absolutely neutral before inoculation, becomes 

 distinctly acid. After long standing the curd contracts somewhat, but little, 

 if any, peptonization appears to occur. On shaking, gas-bubbles arise from the 

 curd ; and when the mUk is provided with a vaseline plug after inoculation, 

 gas accumulates after ten days, and the plug is slightly shifted up the tube. 



(24) Neutral Litmus-Milk. — Within forty-eight hours at 25° C. the litmus is 

 completely turned red. After eight days it begins to be decolourized, 

 beginning at the surface, and proceeding downwards, the process being 

 practically complete in fourteen days. On shaking the tube and exposing the 

 contents in a thin layer to the air, the litmus regains its red colour within a 

 few minutes. 



(25) Production of Indol. — No production of indol could lie traced in 

 cultures up to fourteen days old. 



(26) Action on Starch. — Although the starch-grains in the macerated 

 tissues of stalks and tubers attacked by this organism appear to be intact, it 

 nevertheless exerts a diastatic action on potato-starch paste. To ordinary 

 Ijeef-extract-peptone agar sterilized, thin potato-starch paste was added 

 sufficient to produce a strong blue colour with a solution of iodine in potassium 

 iodide. Plates of this medium were poured and allowed to set, some of them 

 being inoculated m the centre with the organism — one other, used as a control, 

 being not inoculated. After ten days at 25° C. the organism had produced a 

 circular patch of growth in the inoculated dishes, the margin of which reached 

 to within one quarter of an inch of the edge of the plate. On flooding the 

 plates with iodine in potassium iodide solution, and allowing to stand a short 

 time, the portion of the agar covered by the growth (which was not so thick 

 as to prevent the solution from quickly penetrating to the agar below it) 

 remained brown, while the margin turned blue. The control-plate had 

 remained sterile, and a blue colom- developed all over its surface. 



(27) Thermal Death-point. — A prelimmary test of this showed that when 

 the organism was suspended in sterile lain-water, and exposed for ten minutes 

 to a temperature of 50° C, it was entirely killed. Heating for the same period 

 at 45° G. failed to kill. Hence the thermal death-point lies between 45° C. 

 and 50° C. 



(28) Production of an Enzyme. — Doubtless the organism produces an 

 enzyme capable of dissolving the middle lamella of cells. A single attempt 

 was made to obtain it, which was not successful. Owing to the somewhat 

 limited resources of oui- small temporary laboratory, further attempts were 

 not proceeded with. 



