BACTERIAL CONTENTS OF VARIOUS WATERS 113 



in sea- water, found as many as 298,000 in a c.c., but 

 the sample was taken only 50 metres from the entry 

 of the Chiatamone Canal (an excessively foul water 

 containing the sewage of a large part of Naples) ; at 

 a distance of 350 metres the number fell to 26,000, 

 whilst at 3 kilom. only 10 were discoverable. 



Eussell, 1 whose researches in this particular direc- 

 tion were much more extended, examined samples taken 

 from depths of 75 to 800 metres, at distances of 4 

 to 15 kilom. from the shore, and found from 6 to 78 

 microbes in 1 c.c. taken from the surface, and from 3 

 to 260 at various depths below. 



The following table, whilst showing the particular 

 distances from land as well as the various depths at 

 which the samples were taken, brings out very clearly 

 that, whilst the total number of bacteria in sea-water is 

 comparatively small, there appears to be no marked 

 decrease in the numbers corresponding to the greater 

 distance from land of the water selected for examina- 

 tion, all the samples, be it observed, having been col- 

 lected at a distance of upwards of 4 kilometres from 

 the shore, and thus beyond the reach of any littoral 

 influences. 



The Distribution of Bacteria in Sea-iuater both Vertically and 

 Horizontally (Russell) 



Number of 



bacteria in Dumber of bacteria found in 1 c.c. of water taken at 

 taken from the various depths 



surface 



15 



30 



Zeitschrifi fur Hygiene, vol. xi. 1891, p. 177. 



