THE WATER-SUPPLY OF TOWNS IN THE THOriCS 30/5 



"This organism should uot be present in less than 1000 c.c. of deep well-water. Here it has licen foimd in 

 500 c.c. In shallow well-waters it should not occur in 100 c.c, hence it was not necessary to test for it in lesser 

 quantities than half a litre. 



" As regards streptococci they have much the same significance as B. co!i ; in other words, when present 

 in large quantity they indicate fiecal contamination, but their position as precise indicators is not yet assured. 

 It will be noted that they were present in 01 c.c. of the water. As compared with Blue Nile water it is evident 

 that, bacteriologically, the samples of well-water examined were just about four times as bad." 



I was now somewhat in the position of Pooh Bah in the " Mikado." As Government 



Bacteriologist I condemned the water and as Medical Officer of Health I refused to accept 



it. Personally, I was inclined to make a stand for river water and filtration, or at least to 



insist on filtration of the well-water. 



With the scanty information available, it was impossible to come to any definite 



conclusion regarding the source of pollution. Noting, however, a certain ratio between the 



numbers of micro-organisms present in the well-water and those in the Blue Nile water 



I concluded that the river water was finding its way into the wells and, considering 



Dawson's views, which I have already cited, I hazarded the opinion that one or other of 



the soil layers was acting as a culture medium and that, under conditions of increased Probability of 



temperature and favourable nidus, the organisms in the river water were multiplying in situ, ^j.^^^.,^ j,^ g^u 



The type of organism found on the plates favoured this hypothesis. That this view was in layers 



all probability correct I may at once declare, for further investigations proved the existence 



of a bed of bluish shale. 



As there was also a doubt regarding the quantity of water available, it was decided to 

 obtain the advice of Mr. Abel, of Cairo, a well-known hydraulic engineer. He was 

 accompanied by Dr. Todd, of the Egyptian Public Health Department, who acted as 

 Mr. Abel's personal adviser on the bacteriological aspect of the question. Their visit 

 unfortunately took place at a time when the laboratories were partly gutted by a disastrous 

 fire, and Dr. Todd's work had to be limited, but they had the advantage of being given every 

 facility and full information, as it was hoped their investigations would put a different 

 complexion on the case, especially as the air-lift plant had been installed and was in use. 

 So far as the chemical and bacteriological analysis went this was not the case. The work 

 done in the laboratories was amply confirmed, and their report only differed from ours in 

 declaring that any true surface contamination was impossible. In this, I believe, they were 

 perfectly correct. Further acquaintance with soil conditions has assured me on this point, 

 though my chief fear was that water from polluted pools in the river bed at low Nile might 

 find its way into the unprotected bore holes. 



One cannot enter into their interesting enquiries and elaborate tests in detail, but it is Report of 

 useful to tabulate their results. These are as follows : — „ ' -r^^^i 



"The results of the bacteriological tests show that at the time of tlie trials the water 

 was far from satisfactory from a hygienic point of view. 



"The two wells, which were subjected to a more or less detailed examination, gave 

 evidence of a somewhat intense and irregular pollution. 



" For reasons given above, it was not possible to definitely locate the source of the pollu- 

 tion ; but, from the results of certain tests, we were forced to the conclusion that the water 

 which enters the wells from some of the upper layers tapped, must be highly contaminated. 



" How this contamination arises is a question which we are unable to settle, from want 

 of sufficient data ; but we are convinced that any true surface contamination in the 

 immediate vicinity of the wells is out of the question. 



" Concerning the chemical constitution of the water, we are not inclined to lay much 

 stress on the results of the analysis availalale, as these are hardly sufficiently numerous, nor 

 do they cover a long enough period. 



