242 



Profs. Percy Frankland and Marshall Ward. 



the mice were not killed. That some few living anthrax spores were, 

 however, still present in the water was proved by adding some broth 

 to the water, which led to such a multiplication of the anthrax, that 

 in the course of a few days the water thus treated became fatal on in- 

 jection into mice. It is worthy of note in this connexion that one 

 only of the unsterilised Thames waters (First Series) proved fatal 

 without broth being added, and that this water had been filtered 

 through Swedish paper before its infection with anthrax, so that 

 it approached to some extent in its character the sterilised waters 

 (pp. 193—194, 197,200). 



In the case of the unsterilised Thames water again it appears, as far 

 as the evidence goes, that the anthrax spores are better preserved in 

 the water at the winter than at the summer temperature (pp. 193, 197) . 



Daylight again appeared to be slightly unfavourable to the preser- 

 vation of anthrax, the indications in this direction being more 

 marked in the case of the First than in the Second Series of Thames 

 water experiments (pp. 205, 218). 



Sunlight, on the other hand, was most pronounced in its deleterious 

 effect on the anthrax spores in the unsterilised Thames water. In 

 the unfilfcered water they were no longer discoverable by cultivation 

 after 84 hours' sunshine, whilst in the paper-filtered water there were 

 still a few present after 92 hours, but all had disappeared after 

 151 hours' insolation. These waters also which had been thus ex- 

 posed to direct sunshine proved innocuous to mice, nor could their 

 virulence be resuscitated by the addition of broth, clearly showing 

 that the anthrax spores had perished to the last individual (pp. 

 209—212). 



It is especially noteworthy in cpnnexion with these results that they 

 establish the remarkable fact that the anthrax spores, when immersed 

 in water, are less prejudically affected by sunlight than when im- 

 mersed in any of the ordinary culture materials. Thus, it ha3 been 

 shown by a number of observers that the anthrax spores suspended 

 in broth and other culture materials are generally destroyed in the 

 course of a few hours' exposure to sunshine, whilst in the above 

 experiments the anthrax spores immersed in Thames water> both 

 sterile and unsterile, resisted an insolation of upwards of 56 hours. 

 This remarkable contrast between the behaviour of the anthrax spores 

 in an aqueous a,nd a nutrient medium respectively is also in accord- 

 ance with the previous observations of Straus and of Momont, who 

 both however, appear to have experimented with distilled water 

 only'( PP . 212, 213). 



In the unsterilised Thames water experiments of the Second Series, 

 the conditions were different, inasmuch as the w^ater was in the first 

 instance infected with a much larger number of sporiferous anthrax 

 bacilli. On this account, although a great diminution in the number 



