EXAMINATION OF WATER FOR MICRO-ORGANISMS 61 



of taking the sample is the bottle withdrawn from 

 its tin. 



The following instructions for the collection of 

 samples of water for bacteriological examination should 

 be as closely as possible adhered to : 



1. The canister containing the sterilised bottle 

 should not be opened until everything is ready for 

 the collection of the sample. 



2. After opening the lid of the canister, the sterilised 

 bottle is to be lifted out by its stopper, which is seized 

 with forceps previously heated in a name, the bottom 

 of the bottle is held with the fingers of the left hand, 

 and the stopper is then to be screwed off by means of 

 the forceps which are held in the right hand, and on no 

 account must either stopper or mouth of the bottle be 

 allowed to come in contact with the hand or any other 

 object. The open mouth of the bottle is then placed 

 under the tap or spout from which the sample is to be 

 collected, the water being allowed to flow in until the 

 bottle is almost but not quite full. The stopper, which 

 in the meantime has been carefully held with the for- 

 ceps by its handle, and not laid down anywhere, is at 

 once replaced and tightly screwed in, the bottle being 

 lifted back into its tin by the stopper and the lid closed. 

 The tin should be so placed that the bottle remains 

 upright. 



In collecting samples from cisterns, tanks, ponds, 

 rivers, or lakes, it is best to completely immerse the 

 bottle in the water before withdrawing the stopper, and 

 to replace the latter before again raising the bottle 

 above the surface. In this manner any surface scum 

 which may be present on the water is avoided, but at 

 the same time in cases where the w^ater is shallow, as in 

 some streams, any disturbance of the sediment must be 

 carefully prevented. 



