MODERN METHODS OF WATER PURIFICATION. 33I 



strated by the fact that the B. CoH were found invariably in 

 water that had passed the reservoir, but repeatedly samples 

 were taken from the rising main between the filters and the 

 service reservoir, at the same time as they were taken from 

 the water after leaving the reservoir for town distribution : 

 the water from the waterworks main w^as Coli free, and that 

 in the town distribution pipe contained those germs. During 

 1908 they have been present on 8 occasions, of which 3 times 

 in 50 c.c. and 5 times in 100 c.c. only, never recorded in 10 ex., 

 in I c.c. nor in 'i c.c. 



These may or may not have been what Dr. Houston calls 

 tvpical Bacillus Coli in his report on the London water. I 

 had the opportunity of inspecting some of the London sand 

 filters when there, which are under the eflficient control of that 

 distinguished expert, who is the scientific head of the London 

 Water Board, and everything possible to secure the best re- 

 sults is done or attempted, where sand filters are there in their 

 own home. In his admirable report for 1907-1908, a report 

 which for fullness of interest and clear and acciu'ate statement 

 is a model, on page 18, where there is a summary of the results 

 of bacterial work for the year, and of 5,512 samples of filtered 

 London Thames water Bacilli Coli (underlined by Houston as 

 typical Bacilli Coli, and therefore excluding " Coli ahnliche 

 bacillen," Coli-like germs but not typical) were found in a little 

 over 20 per cent, of all the samples of filtered Thames water 

 examined, that is about one-fifth of all the London Thames sand- 

 filtered water had typical B. Coli in 100 c.c. or less; 5'9 per 

 cent, of the samples had them in 10 c.c, r6 per cent, of the 

 samples contained them in i c.c, and some even showed this 

 in i-ioth of a c.c, i.e., in about two drops of water. 



We have not had any record of Coli in anything under 

 50 c.c. So where sand tnlters should be at their best (and for 

 the richest city in the world there should be no shortage in 

 area) there is evidence of water far inferior to that which we 

 have enjoyed here, and the immunity from water-borne disease 

 during the past two years, and particularly during 1908. has 

 been the greatest recorded in Bloemfontein. So the Coli 

 found did not indicate any pressing inadequacy of filters caus- 

 ing danger of water-borne disease, as they were not in the 

 water issuing from the waterworks, and they were probably, in 

 the absence of any record to the contrary, largely coli-like 

 bacilli, and not typical. Houston's figures of proportion 

 between typical and non-typical coli bacilli from 3,830 speci- 

 mens was 54'4 per cent, typical, and 45*5 non-typical. 



The Town Council of Bloemfontein has striven after purity 

 of water supply, and its otficials concerned, the City Engineer 

 and Medical (Jfiicer of Health, as well as the Government 

 Public Health officials, are all imbued with the desire and in- 

 tention to at all times do all possible to attain the best purifica- 

 tion, and we all are anxious to get the best means. And when 

 the town increases more filtering will have to be provided, and 

 Ave must decide what it is to be. 



A Commission, consisting of Dr. Yule, Dr. Guise Moore and 

 myself, in 1902 dealt with water purification in a full report in 



