4 The Examination of Waters. 



jelly is too stiff they do not seem to have the power to 

 act. At the time I was making my experiments the tem- 

 perature of the laboratory often rose to 80° F.. and, as at 

 this temperature the 5 per. cent, jellies became liquid, the 

 bacteria were able to move freely through the tubes, the 

 experiments were lost. 



I then used the well-known solutions of tartarate of 

 ammonia, phosphate of sodium, sugar, and nitrates, singly 

 and mixed, having previously carefully sterilised them by 

 boiling, and using precautions to prevent outside contamina- 

 tion, and as a check testing distilled water contaminated by 

 the air of the laboratory. In these experiments the Yan 

 Yean (filtered) was the only natural water which would not 

 develop its germs without the addition of ammonium 

 tartarate. When mixed with sugar the mud separated from 

 the Yan Yean water by a high-pressure filter produced 

 alcohol — (another exception, which can hardly be called a 

 natural water, is the water from the Lovely Banks Reservoir, 

 which has been treated by lime) — while all the other waters 

 became offensive, producing ropy liquids undergoing putre- 

 factive changes, giving off hydrogen, and smelling at times 

 of butyric and lactic acids. 



Most of my experiments were repeated several times, and 

 I noted that in those waters which contain the germs of 

 many varieties of bacteria the sequence of development 

 and duration of the existence of each class or variety might 

 be varied by slight alterations in the method of treatment ; 

 -and this may in some measure account for the contradictory 

 statements made by scientific observers as to the types 

 found in certain waters, and the chemical changes produced 

 by them. With this part of the subject I hope to be able to 

 deal at a future time, but in this inquiry I was satisfied 

 in obtaining evidence which confirmed the results of the 

 chemical tests, proving the contamination by filth, and that 

 the germs introduced by this filth contamination were still 

 active. While these experiments were being conducted I had 

 the opportunity of visiting one of the watersheds in question 

 — the Moorabool — under the guidance of Mr. Wm. Davidson, 

 the engineer of the Yan Yean Water Supply, and found that 

 the river, with its tributaries, is simply the drain of a pas- 

 toral and farming district, with a rapidly increasing farming 

 population. 



Some pure water may get into the river from springs 

 along the banks, and before the recent rain these springs 



