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Profs. Percy Frankland and Marshall Ward. 



deprived of all their bacteria, by filtration through porous porcelain ; 

 and (3) sterilised by heat, 100° C. ; (4) experiments have also been 

 made with distilled water. We regard these several conditions of 

 the waters referred to as essentially different one from another (pp. 184, 

 185,213,214,228). 



7. Into snch waters we have introduced the Bacillus anthracis 

 (anthrax) in the form of (a) vegetative bacilli (pp. 256 — 278) ; (6) 

 spores (p. 278) ; (c) in the " asporogenous " variety (pp. 274 — 278) ; 

 contrasting also the effect of using large and small quantities of this 

 micro-organism, and of employing it in a virulent and an attenuated 

 or weakened condition respectively (pp. 184, 213, 228). 



8. The principal factors to which we have devoted attention in 

 these experiments have been (1) the temperature at which the 

 infected waters were maintained ; (2) whether they were exposed to 

 light or preserved in darkness : (3) the presence or absence of other 

 organisms besides anthrax in the waters (pp. 184, 214, 228 ; all ex- 

 periments were conducted in the dark, excepting when otherwise 

 stated, 40, 45, 54, 57, 59, 67, 69, 71; 92, 119, 126—134). 



9. We will in the first instance call attention to the results which 

 we have obtained in our experiments with these spores. 



We found that the behaviour of the spores was very different, 

 according as they were introduced into the unsterilised or sterilised 

 waters respectively (pp. 181 — 243). 



10. In the sterilised waters their behaviour was practically uni- 

 form, irrespectively of whether Thames or Loch Katrine water was 

 employed, irrespectively of whether the water was sterilised by filtra- 

 tion through porcelain or by steam, and also irrespectively of whether 

 the waters were preserved at a summer temperature of 18 — 20° C, 

 or in the refrigerator at 4 — 9° C. In all cases the spores retained 

 both their vitality and their virulence for many months. After this 

 prolonged residence in these sterile waters, they were recognisable by 

 cultivation in either the same or in only slightly diminished numbers 

 from those in which they were originally introduced into these waters. 

 These infected sterile waters, after standing for upwards of seven 

 months, were also invariably fatal to the animals into which they 

 were inoculated (pp. 200, 219, 232, 234, 238). 



11. The same results with these infected sterile waters were 

 obtained irrespectively of whether they were preserved in absolute 

 darkness or freely exposed to diffused daylight. Direct sunshine, 

 on the other hand, was rapidly fatal to the anthrax spores in these 

 waters within 84 hours. In the waters so insolated anthrax could not 

 be detected by cultivation, and animals inoculated with these waters 

 remained alive. But in order to make absolutely certain that the 

 anthrax spores were quite extinct in these insolated waters, we incu- 

 bated them with some sterile broth, so that if only a single spore had 



