155 



Storage reduces the number of bacteria of all sorts. If suffi- 

 ciently prolonged, storage devitalizes the microbes of water-borne 

 disease (typhoid bacillus and cholera vibrio). An adequately stored 

 water is to be regarded as " safe." 



The use of stored water enables a constant check to be main- 

 tained on the safety of London's water, antecedent to and irres- 

 pective of filtration. It renders any accidental breakdown in the 

 filtering arrangements much less serious. 



The habitual use of stored water would lighten the grave res- 

 ponsabilities of the Water Board as regards the safety of the London 

 water supply, and would tend to create a sense of security among 

 those who watch over the health of the metropolis. 



Raw river water should be stored antecedent to filtration prefer- 

 ably for 30 days. The question of whether the 30 days' storage 

 should be fixed on a maximum or a minimum basis must be left 

 unanswered; but if the former alternative be chosen, the desira- 

 bility of employing supplementary processes of water purification 

 to tide over emergencies is worthy of consideration. 



SIMS WOODHEAD. The Results of Sterilisation Experiments 

 on Cambridge Water. (Cambridge Philosophical Society, 

 June 6th 1910). Nature, Vol. 84, July i4th, 1910, p. 63. 



Sterilisation by chlorine and chlorine compounds gave most 

 startling results. In a series of preliminary experiments, it was 

 found that i part of available chlorine to 2 million parts of water 

 was sufficient to kill all non-spore-bearing bacteria of the Bacillus 

 coli type, and therefore of the typhoid bacillus type, and probably 

 also of the cholera bacillus type. Sterilisation occurred within half 

 an hour, even in the presence of appreciable amounts of organic 

 matter. 



A. H. HAYES. A new suggestion for the preparation of po- 

 table water. (Journ. Roy, Army Med. Corps, 14 [1910], 

 I No. i, pp. 75-77, figs. 2). E. S. It. June, 1910. Abstr N. 9. 

 A simple portable apparatus tor the clarification of muddy 

 ter by means of a gelatinous precipitate of aluminium hydroxide 

 described, and tests of its efficiency are reported. 



