254 Timehri. 
numbers, indicates old or a slight recent pollution. The Streptococcus 
Faecalis is indicative of very recent fouling probably dating from only a 
few days previous. 
The Bacillus Lactis Aerogenes usually indicates a pollution of a few 
weeks old and if the Bacillus Coli Communis is absent indicate that a 
moderate amount of purification has taken place. 
The Bacillus Cloacae and Neapolitanus are found most frequently 
when the fouling has been remote, possibly months old. 
The Bacillus Oxytocus Perniciosus is a delicate organism and is 
eloquent of very recent pollution. 
The Bacillus Rhinoscleroma is rare in any but human excreta and 
therefore is indicative of the fouling being of human origin. 
In conclusion it should be recollected that when water supplies are 
improved, not only does the case incidence and death rate from water- 
borne diseases show a marked decrease, but the improvement of the 
water supplies has invariably been followed by a general all-round 
improvement in the health of the community. This we cannot impress 
too greatly on the villages and estates of the colony, for the village water 
supplies are usually in a far worse condition than those on the estates. 
In thus completing the first bacteriological study of estates’ water 
supply many difficulties have necessarily presented themselves and 
many unsuspected sources of error arisen. European standards have 
been found wanting and the customary methods of work have required 
adaptation to peculiar local conditions. Much of the work has thus been 
necessarily groping in a mass of facts for true actualities which may be 
safely used for comparative results. 
The subject, however, has been conceived from a critical standpoint 
and practical conclusions have been drawn only when they are thoroughly 
justified by the available evidence. The object has been to get as far as 
possible a firm bacteriological and chemical basis and then to explain the 
scientific experiments upon which these are based and the lines along 
which future work should develop. 
as 
