446 The Philippine Journal of Scie7ice mz 



Results such as are exhibited by Table I raise the questions 

 as to whether or not the water as it conies from the source is 

 absolutely sterile and whether or not the few growths which 

 appeared in the media are contaminations. In practically every 

 well some algae were growing inside the mouth of the exit tube 

 and under the stream of water, and it may be from colonies of 

 bacteria among them that some of the growths came. 



In a well (Malolos, barrio Mambong) flowing 23 liters per 

 minute, samples were taken, and afterward the mouth of the 

 exit tube was thoroughly scrubbed with stiff test-tube brushes. 

 Four and one-half hours later a second lot of samples was taken. 

 Both lots of samples gave a high degree of purity, but the second 

 was not superior to the first. This experiment was repeated 

 v/ith another well (Paombong, church square) having a flow of 

 57 liters per minute. Here only a few minutes intervened 

 between the first and second tests. There was little difference 

 between the two tests; both were nearly, but not quite, sterile. 

 Four cubic centimeters of ordinary broth were added to 10 cubic 

 centimeters of this water and the mixture remained clear two 

 days at high room temperature, becoming clouded only on the 

 third day. 



Even if all sources of contamination within reach could be 

 eliminated, there would still be a possibility of contaminants 

 growing on the casing deep in the ground. Further, before 

 absolute sterility could be proved, it would be necessary to em- 

 ploy all sorts of media, nonnitrogenous and otherwise, in order 

 to eliminate every possible kind of bacterium; and there would 

 still remain the possibility of the presence of thermophiles of 

 different grades and of forms unable to grow on any artificial 

 medium. It would, therefore, be a difficult, if not impossible, 

 task to prove absolutely the sterility of a water of this sort. 

 The relative freedom of these waters from bacteria seems the 

 more remarkable when we consider that they are at a temperature 

 (28° to 32°) which is very favorable to the growth of most 

 bacteria. 



A number of kinds of bacteria were found in these wells, 

 but the commonest type was an actively motile bacillus, readily 

 forming zoogloea. 



2. PUMPING WELLS 



While the flowing wells examined are located near the coast, 

 most of the pumping wells are 8 kilometers or more inland; 

 although two of them are near the coast and in the immediate 

 neighborhood of flowing wells. 



