8o 



MICRO-ORGANISMS AND DISEASE [chap. 



London water companies, but also on several occasions 

 during the examination of samples of the water taken once; 

 a week during January and February, 1895, in the filtered 

 waters distributed by the London water companies. This 

 is shown in the following table : — 



6lh 

 week. 



7 th 

 week. 



8th 

 week. 



+ ^ Bacillus coil in London waters. 



The third test to which drinking waters ought to be sub- 

 jected, is the microscopic examination of its suspended 

 matter, particularly as to the presence of protozoa. 



The water remaining after the quantity required for 

 above filtration had been withdrawn is put away and allowed 

 to stand in a cool place for twenty to twenty-four hours. 



By means of a pipette drawn out into a long capillary 

 tube 5-8 cc. or more are drawn up from the bottom layer, 

 the end of the capillary tube is sealed and the pipette fixed 

 in an upright position so as to allow the suspended matter 

 to settle in the capillary tube. When this has taken place, 

 the capillary tube is broken off and its contents subjected 

 to microscopic examination 



I will give here a table showing what kind of living ani- 

 malculi were found by me in examining the " filtered " water 

 as distributed by the various London water companies 

 during six weeks of examination, and from this it will be 



