94 
THOMPSON YATES LABORATORIES REPORT 
7. Daily, fortnightly, and monthly bacteriological analysis of the Liverpool water supply. Special 
investigations. 
The work undertaken by the department is, therefore, partly routine and partly research ; 
the opportunities for the latter being especially great in an important centre like Liverpool. 
The following are the directions followed out in the Bacteriological Analytical 
Department : — 
The Following to be Kept Ready to Hand 
Nutrient agar stock tubes. 
Carbolized (i-iooo) nutrient agar stock tubes. 
Nutrient gelatine stock tubes. 
Glucose nutrient gelatine stock tubes. 
Litmus milk tubes. 
Pyrogallic acid, i oz. in 300 c.c. water, about i grm. in 10 c.c. 
Normal caustic potash solution. 
Sterilized Petri dishes. 
Sterilized i oz. bottles with india-rubber stopper, for collecting samples of water. 
Sterilized 12 oz. bottles with india-rubber stoppers, for collecting samples of milk. 
Sterilized plugged test-tubes. 
Sterilized pipettes. 
The special agar water bath to be kept at 45^ C. In this, agar tubes melted by placing them in 
boiling water are to be immersed, so that they may cool down to 45'' C. and remain at that temperature 
ready for use. Gelatine tubes can be liquefied in this bath before use. 
The special bath for keeping milk tubes at a temperature between 70° and 80" C. to be one-third 
filled with boiling water every morning, and cold water added, if necessary, till it falls to 80° C. ; a small 
flame is then to be kept burning beneath. 
To separate Spore-bearing Micro-organisms the inoculated tubes should be placed in the bath. 
A test-tube containing about 20 c,c. cold water is placed in the centre, and when the lid is put on the 
bulb of the thermometer should be immersed in the water. By this means the thermometer will show the 
temperature of the liquid inside the test-tubes. 
The tubes should be left for 1 5 minutes after the thermometer registers 70° C. The temperature 
will never rise above 80° C, which is the boiling point of the Benzene placed inside the double jacket. 
For Anaerobic Cultivations 
Wide mouth bottles with glass stoppers or Buchner tubes to be used, according to the number of 
tubes to be incubated. 
For each 200 c.c air capacity of the bottle or Buchner tube pour in 10 c.c. of the pyrogallic acid 
solution by means of a funnel, and, immediately after, i c.c. normal caustic potash solution for each 10 c.c. 
of pyrogallic acid solution used. 
The tubes to be incubated anaerobically should be placed in the wide mouth bottle or Buchner tube 
before the mixture is poured in, and the stopper put on immediately after. 
In using a large bottle it is better to let it remain in hot water, so as to expand the air before the 
mixture is poured in and the stopper closed ; if this is not done the expansion of the air when the bottle is 
placed in the incubator is likely to raise the stopper. 
Water Analysis 
For Liverpool Corporation water, or water known to be pure. 
Gelatine. — Add i c.c. to a gelatine tube liquefied in the bath at 45° C, and allowed to cool 
slightly. Pour into a sterilized Petri dish. 
