A CURIOUS and unsuspected source of pollution of drinking-water has just been discovered in Cattar-augus County in western New York State (William G. Hassler in Natural History, New York, May-June, 1932, p. 303). Certain spring supplies of water continued to give unsatisfactory laboratory tests even after drastic steps had been taken to protect the springs from outside pollution. Further examination revealed that salamanders, large newt-like amphibians, belonging to four different species, occasionally occurred in the springs, and though a first examination showed that only a small percentage contained the colon bacillus, the investigation was continued. Nearly two hundred purple salamanders (Gyrino-philus porphyriticus) were marked with identification discs, and subsequent collecting proved that sometimes individuals wandered as much as sixty-five feet from the stream, apparently in search of food. One was observed eating fly larvæ which were living on mammalian refuse, and this settled the question of how colon bacilli entered the food canals of the salamanders. A second surprise was sprung upon the investigators when they studied more closely the numbers of salamanders in the springs themselves. Purple salamanders were not thought to be particularly common, but repeated nightly visits resulted in a catch of 144 in one spring, which contained about fifty more uncaught. Yet there were occasions when not one of these salamanders could be found, although all the catch was marked and returned to its spring. Laboratory experiments gave some idea of the extent to which contamination might take place. Over a period of 122 days, one salamander excreted a sufficient number of colon bacilli to contaminate 237 gallons of water heavily enough to be considered dangerous on every test. It is believed that the creatures act as reservoirs or incubators, and once infected with colon bacilli, continue to excrete them so long as there is food in the stomach or intestines to supply nourishment to the bacteria.