'2'.)-l TIIK VVATElt-SUl'l'hV OV TOWNS IN TllK TllOl'lUS 



suiiiiiior, tlio actual iiuiiibor of ' true coli ' is nuicli li'ss than in winter, due, undoubtedly, 

 to the action of the sunlight in killing off these susceptible organisms. 



"Consequently, when an analyst in England finding 'true coli' in 1 c.c. condemns a 

 water, because it shows recent pollution, he is right in a great majority of the eases, and 

 in the remainder the worst that can be said of his opinion is that he has slightly erred 

 on the side of over-caution, for it must be remembered that the whole of the 10 organisms 

 comprising his ' true coli' are originally of fiecal origin. Now in India, things are entirely 

 different. The coli commiinif of Escherich is a very rare organism in the waters of this 

 country, whereas the other organisms that are included in Houston's definition are 

 extraordinarily common."* 



Considering those facts, and also that the bacteriological flora of the faeces of num 

 and animals varies at different times of the year, he came to the following conclusions: — 



liactcrinl " 1. That standards in use in cold cliiiiates are useless and worse than useless in 



standarcis iimst , . . , - 



,._ . tropical countries, 



diner m ' 



temperate aiui " 2. That it is necessary to separate the individual species of bacilli by well-established 



tropica tests and to studv their characteristics and their position in nature. 



tliniates " ■*■ 



"3. That it is advisable to classify all lactose-fermenting organisms according 'to 

 their ability to resist the action of sunlight and on this to base the standard of 

 bacterial purity." 



In the first place, the bacteriology of earth known to be heavily polluted with liuiiiaii 

 excrement was studied. 



The results are summed up as follows : — 



" 1. Bacillus cloacie, bacillus grunthal, bacillus No. 75, and to a less extent bacillus 

 coscorolia are capable, under favourable conditions, of remaining alive in the soil for a 

 considerable length of time, probably ujj to 3 or 4 years. 



"2. Faecal organisms of any kind do not appear to exist in large numbers after they 

 have been in the earth for longer than 1-2 years: night-soil buried in the ground, even 

 in large quantities, loses most of its organisms in this period. 



" 3. Hporoijenes enteritidis spores are capable of remaining alive in the ground for 

 a period of something between 3 and 4 years. 



"4. Bacillus coii coiiinumis has never been isolated from the trenching ground samples; 

 hence it is probable, though not certain, that this organism does not remain alive in 

 the ground as long as the more resistant organisms like cloaca?, etc. It has been 

 proved in one experiment to exist in the ground for a period of 97 days." 



Next the change in the bacteriological flora of water and fajces during monsoon 

 weather was made the subject of an investigation which showed : — 

 Kactvriai ttora "1- That the Conditions obtaining during a time of heavy monsoon weather when 



in water during f,.gjjh fiEces may find their wav easily into water, the whole country being submerged, 



the monsoon . •' . j .00 



is in some w'ay connected with the appearance of a set of rare micro-organisms in all 

 the water-supplies over a wide area. This fact has not been noticed with previous 

 and subsequent heavy rain. 



" 2. That these and allied bacteria may suddenly become extremely common in the 

 fiBces of man and animals. The cause of this increased prevalence is unknown. 



"3. That flood conditions having passed away, the bacilli very rapidly disappear 

 troiii all waters. Consequently this supports the suggestion that these organisms are 

 especially susceptible to natural forces inimical to bacteria." 



* la this coancctiou ouc may uotc that recent work by Castclliiui ' '' goes to sliow tliat tbe typical B. cult 

 of Esuhcrich is rare in the intestines of jxirsons living in Ceylon. 



