BACTERIAL CONTENTS OF VARIOUS WATERS 101 



receives the sewage of Braemar). This accession is 

 marked by a large increase in the number of microbes, 

 there being found as many as 2,829 in a c.c. Another 

 sample was taken above the Bridge of Ballater, and it 

 shows that the number of micro-organisms has been 

 reduced by rather more than one-half in the flow from 

 Old Mar Castle to this point, for only 1,139 were found in 

 the c.c. A sample examined from the Dee 100 yards 

 below the Ballater sewage-pond outfall, on the other hand, 

 shows a large increase in the number of micro-organisms, 

 as many as 3,780 being obtained from a c.c. The cause 

 of this increase, notwithstanding the very small quantity 

 of liquid coming from the pond at the time (10 o'clock 

 in the morning), is not far to seek ; for as many as 

 235,000, 273,000, and 26,000,000 organisms were found 

 in the effluent from the sewage-pond, and the sewage- 

 outfall channel above the pond at Ballater respectively. 

 On following the Dee down, a sample was taken above 

 the junction of the Neil Burn, Kincardine o' Neil, and it 

 was found that the micro-organisms had again fallen to 

 .about the same number as above Ballater, the number 

 amounting to 938 in the c.c. Below the entrance of the 

 Neil Burn, which at the time of the investigation was a 

 mere dribble, the number of micro-organisms had again 

 perceptibly risen, 1,860 being found in the c.c. The 

 Neil Burn itself, twelve yards below sewage-outfall, was 

 found to be very rich in micro-organisms, as many as 

 1,200,000 being obtained in the c.c. The river on 

 reaching Invercannie, however, again exhibits just about 

 the same number of micro-organisms as above Kincar- 

 dine o' Neil or above Ballater, only 950 being found in the 

 .c. The total number of miles of the river's flow which 

 was covered by the examination was upwards of 40. 



The river Dee thus affords a most perfect example 

 of the repeated pollution and repeated restoration of a 



