[ 4 ] 
land in the catchment area and in one of the streams no human habitation 
111s compares unfavourably with hill streams of a similar character in 
temperate climates. 
,, * n . the , water from both streams 5 cc. give a good reaction with 
MacConkey s medium m 24 hours but not with 2 cc. or 1 cc. No indol ! 
forming organisms were found in 5 cc. of either. These waters, therefore, 
may be considered as fairly good. 
Four streams were examined at Ampang. These form the main : 
supplies to the Reservoir. The catchment area, now 1,500 acres, is rigidly 
preserved. There is no cultivated land in the area and no human 
habitations or domesticated animals, but there is a certain amount of game. 
The hills are of granite and thickly covered with trees and jungle. 
I he streams varied from each other and from time to time and the i 
number of organisms was affected by the rainfall. After long continued 
dry weather the lowest number was obtained 104 per cc., but after very 
heavy rain, 2 in. in 12 hours, the number 148 was not much greater. 
With moderate rains after a spell of dry weather the highest reading 2,120 
was obtained. 
As regards the four streams in ordinary weather 400 to 800 organisms 
peL cc. were found. Most of the observations were made in June and July 
by Dr. Finlayson and myself. Previous observations had been made in 
October, 1903, and in January, 1904, with similar results. 
With MacConkev’s medium acid and gas forming organisms were 
found to be present in each stream, but the amount of water required to 
give the reaction varied from time to time. With .1 cc. at one time three of 
the streams gave the reaction and with .4 cc. the other. 
At other times no reaction was obtained with 2 cc. but this was highlv 
exceptional and a positive result was always obtained with 5 cc. 
Indol forming organisms were not always present in 5 cc. of the water 
but were always found in the sediment from the water. Examination of 
the stream water at the small granite island Pangkor Laut gave very similar 
results, 300 to 500 organisms were found per cc. Acid and gas forming 
organisms were present in 1 cc. and Indol forming organisms in 5 cc. 
No cultivated land, no human habitations and no domesticated animals 
existed in the catchment area but wild pig were abundant. None of these 
waters can be considered as satisfactory from the bacteriological point of view. 
The Public Health question is a difficult one. The character of the 
catchment areas in these places renders sewage contamination impossible 
and the risks therelore of diseases such as 1 yphoid and Cholera which are 
conveyed only from man to man by the contamination of the food, water or 
other injesta with ejecta of persons suffering from these diseases can be 
definitely excluded. 
The existence in nature of classes of organisms closely related to the 
human intestinal organisms capable of living and multiplying in artificial 
media at temperatures and in the presence of substances such as bile salt 
inimical to many natural organisms and which are pathogenic in various 
degrees to the lower animals, is a matter of great importance. 
It is difficult to exclude the possibility that such organisms are agents 
in tne prevalence of intestinal disease amongst persons travellin 0- or working 
m the jungle. 
4 he history of the occurrence of dysentery amongst the troops engaged 
in the Bentong Expedition is of interest in this connection. 
