Use of the membrane filter in the bacteriological examination of water

Molecular or milli‐pore filter membranes have been used for a number of years in Europe. The Goetz type, recently introduced in America, not only retains all micro‐organisms from a large volume of liquid but also can be placed in contact with an absorbent pad soaked with concentrated nutrient solution; this solution passes through the pores of the membrane to the bacteria deposited on its surface, so that they can be cultivated in situ. The work described below is a preliminary survey to assess the possibility of applying membrane‐filter technique to media and methods commonly used in Britain for the bacteriological examination of water. The chief advantages of the technique are concentration of micro‐organisms, removal of inhibitory substances and saving in glassware and in media preparation. Further investigations proposed include the examination of a series of samples, the development of a procedure for achieving a rapid result and the isolation of pathogenic organisms from sewage effluents and polluted waters.