90 SEWAGE AND ITS PURIFICATION 



4-foot bed, the spores of B. enteritidis varied from lo to i,ooo 

 per c.c. In the effluents from the 6-foot coke-bed and from the 

 laboratory vessel they varied from lo to lOO per c.c. ; but 

 there may have been more spores present, as the minimum 

 amount of liquid added to the milk-tubes was o'oi c.c. 

 Houston continues : 



" Judging the results as a whole, it cannot be said that the 

 biological processes at work in the coke-beds produced any significant 

 alteration in the number of spores of this pathogenic anaerobe. 

 This is the less to be regretted, since the effluents are discharged 

 into a large tidal river below locks, the water of which is not used 

 for drinking purposes. Still, it is to be thought of that the cultures 

 of B. enteritidis sporogenes are extremely virulent, and that Dr. Klein's 

 results seem to prove that this anaerobe may be causally related to 

 acute diarrhoea. At all events, it is highly important from a practical 

 as well as from a scientific point of view to continue these observa- 

 tions on the number of spores of B. enteritidis in crude sewage and in 

 the effluents from the coke-beds." (This was done in 1899,^ ^^^ ^^ 

 was noted that, although the number of these spores was frequently 

 less in effluents than in the sewage, it was still between 100 and 

 1,000 per c.c.) 



On the other hand, in a preliminary Report to the Royal 

 Commission, Professor Boyce, from experiments with this 

 organism, concludes as follows : 



" Filtration has a marked effect in keeping back this bacillus, 

 especially when combined with precipitation. It was not found in 

 the filter effluent from the septic tank at Manchester, nor in the 

 pure fflter effluent at Chorley or Oldham. It was, however, obtained 

 in the former by filtering a quantity through a porcelain filter, and 

 subsequently scraping the surface. The addition of lime and copperas 

 does not appear to have much effect on this bacillus." 



In concluding, Dr. Houston adds : 



" Judging the experiments as a whole, it cannot be said that the 

 biological processes at work in the coke-beds effected any marked 

 alteration in the number of B, coli. It must not, however, be tooj 

 lightly considered that this implies that the effluent was necessarily 

 of an offensive and putrescible character. B. coli and other putre- 

 factive bacteria no doubt work in the direction of purifying the 

 sewage, and their presence in the effluent might only mean that the 

 purification had not been carried sufficiently far to allow of a 

 decrease in their numbers, owing to the incomplete reduction of 

 the organic matters on which they feed, and which allow of their 

 continued multiplication. Yet, when this has been said, it must 

 also be admitted that the passage of an aerobic non-spore-forming 



J London County Council Re fort, July, 1900. 



