COLLECTION OF WATER. 5 



point with a pair of sterile forceps. The water will run in and 

 fill about two-thirds of the tube ; the point is then sealed up by 

 heating with a spirit lamp. When examining lakes and rivers 

 it is often desirable to take specimens from various depths. 

 This may be done by using MiquePs apparatus, which consists 

 of a glass bulb weighted below and suspended by a wire marked 

 in feet or metres. The neck of the bulb is drawn out to a fine 

 point and bent like a swan's neck. A second wire, running 

 through eyes on the suspension wire, is bent at the end into a 

 loop which is placed round the neck of the bulb. When the 

 required depth is shown on the suspension wire, the second wire 

 is pulled sharply so as to break the neck and allow the water to 

 enter the bulb. The same result may be obtained by weighting 

 the ordinary glass bottle and supporting it by means of a 

 string knotted at intervals of a foot. A second string is tied 

 round the glass stopper, which should be partially unscrewed so 

 as to be easily pulled out when the required depth is reached. 

 The samples should be examined immediately after collection ; 

 if this cannot be done they must be packed in ice for trans- 

 mission to the laboratory. It has been found that wJien the 

 temperature is kept below 5 C. there is practically no increase 

 in the number of micro-organisms in the water. This effect 

 appears to be due, not to an immobilising.of the bacteria, but 

 rather to the fact that cold acts differently on certain species, so 

 that the deaths of some organisms are balanced by the births 

 of others. In order to keep the temperature of the sample 

 below 5 C- during its conveyance to the laboratory, Miquel 

 recommends the following procedure to be adopted. The glass 

 bottle containing the sample is placed in a cylindrical metal box 

 just large enough to hold the bottle firmly. The metal box is 

 placed inside a second slightly larger metal box and the space 

 between the two boxes is filled with sawdust. The whole is 

 then placed in a much larger metal box, which is filled with 

 from six to eight pounds of ice broken up into pieces about 

 the size of a walnut. The third metal box is placed in a wooden 

 box and the space between them is filled with sawdust. The 

 lid of the wooden box, which is provided with a handle, is then 

 clamped down. Pakes has suggested a very useful box for the 

 same purpose. The box is made of wood and lined with 



