294 Profs. Percy Frankland and Marshall Ward. 



The fourth set (D) was prepared exactly as C, but kept in boiling 

 water for fifteen minutes. 



When all were ready, and the heated tubes had cooled to 25 — 26° C. 

 just sufficient to solidify the gelatine, a large loopful of anthrax spores 

 was placed in each tube, and all four sets put into the dark incubator 

 at 20° C. 



The results were less satisfactory, as regards sharpness, than we 

 hoped, but it was clear that the spores of anthrax were still there, 

 and alive in all the tubes, after three weeks. 



Finally, the following careful set of experiments were made : — 



A quantity of Thames water, collected on the morning of December 

 10, was at once filtered through a Chamberland porcelain tube at 

 low pressure, the whole apparatus having been very carefully steril- 

 ised. Control experiments showed that this sample of water was 

 almost entirely devoid of water organisms. 



Two similar flasks were prepared, and into these 1 litre of the 

 above water was distributed after the water had been infected as 

 follows : — 



To the 1 litre of filtered water 1 c.c. of a liquefied gelatine culture 

 of anthrax, consisting almost entirely of rodlets and filaments, but 

 partly of spores, and 1 c.c. of a similar liquid culture of B.fluorescens 

 liquefaciens were added, and thoroughly shaken up. 



Each charged flask was then placed in the dark, one at 12° C, the 

 other at 20° C, and plates made daily, as shown in Table y, which 

 summarises the results. 



