208 



Profs. P. F. Frankland and Marshall Ward. 



These authors prove that very minute traces of organic materials in 

 a water induce rapid multiplication of certain species, that the tempe- 

 rature and quiescence of the water are important, and discuss the 

 question as to the effects of mechanical shakings* of the waters, e.g., 

 in transit. They leave this matter undecided, but are of opinion that 

 it will have to be reckoned with by bacteriologists. 



As regards pathogenic species, they found that Bacillus antliracis 

 multiplied in the dirty water of the River Panke, both normal and 

 when sterilised by heat,f so long as the temperature was high enough 

 (12—15° C. to 30—35° 0.) ; but that at low temperatures the bacilli 

 did not nourish, and even died off. 



Typhoid bacilli (" ileo-typhus ") lived for some time, and even 

 multiplied, in (sterilised) ordinary drinking water, as well as in the 

 (sterilised) bad waters. In distilled water they gradually died out, 

 though they may require twenty days or more to do so. In non- 

 sterilised waters they found that they grew so slowly that they were 

 swamped by other forms on the gelatine-plate test-cultures, thus 

 showing how difficult it is to obtain a satisfactory result in such 

 experiments. 



To obviate this difficulty they placed the typhoid bacillus in 

 selected waters, containing selected water bacteria, and they then found 

 that it lived so long that they felt constrained to warn us that this 

 dangerous form may maintain itself for weeks : they also prove that 

 milkj is a good vehicle for it, and that the belief in the danger of 

 washing milk-cans with water containing typhoid bacilli is a well 

 founded one. 



Cholera spirilla were found to maintain themselves for seven days 

 at least in all kinds of sterile waters, and to be still present in some 

 cases even after eighty-two days. In unsterilised waters, however, 

 this form is soon overcome. Here, as in other cases, the temperature 

 was found to be important. 



A curious result is worth noting. They found that the cholera 

 spirilla take some time to accommodate themselves to the exigencies 

 of a water containing competing forms, and consequently the latter 

 usually dominate and eliminate the former. But in certain cases the 

 cholera spirilla do accommodate themselves to the circumstances for a 

 time, and if such specimens be then removed and placed in a fresh 

 sample of the water they multiply at once, and are much more 



* With full reference to previous literature. 



f None of the experiments were made with water sterilised by filtration only. 



X See also "W. Hesse (" Unsere Nalrrangsmittel als Nahrboden fur Typhus unci 

 Cholera," ' Zeitsch. f. Hyg.,' vol. 5, 1889, p. 527); Kitasato (" Das Verhalten der 

 Cholerabacterien in der Milch," ' Zeitsch. f . Hyg.,' vol. 5, 1889, p. 491) ; Almquist 

 (" Neue Erfahrungen iiber JSTervenfieber unci Milchwirthschaft," ' Zeitschr. f. Hyg.,' 

 vol. 8, 1890, p. 137). 



