12 Fungus Flora of Water Supplies 



and the tank then filled and approximately 2,000 gallons of water allowed 

 to pass through the filter. The outlets vary from four to eight inches in 

 diameter and much of the water passed through the netting beyond the 

 wool. This was necessary to prevent the filter from bending, but sufficient 

 water passed through the cotton-wool to yield an adecjuate supply of 

 bacteria and fungus spores. When the tank was empty, the filter was 

 removed, wrapped in a new piece of sterile brown paper and taken to 

 the laboratory for examination. In sampling the water direct from the 

 main, from brooks and ponds, the filter was fixed under the inlet pipe 

 which fills the tank, protection from aerial infection being provided by 

 tying a piece of sterile paper above the pipe and filter. The cotton-wool 

 plug and the debris held by it was transferred as quickly as possible to 

 500 c.c, of physiological salt solution, shaken for five minutes and dilu- 

 tions of 1/25 and 1/250 then made in further salt solutions. 1 c.c. was 

 removed from each dilution and plated upon the following media: 

 (1) Quaker Oat Agar (Clinton) (2), (2) Modified Egg- Albumen Agar 

 (Waksman)(G), (3) Cook's Agar No. II (Cook)(i), (4) Potato Agar. 



Potato agar yields a rapid luxuriant growth suitable for preliminary 

 examination, but the plates are often too badly contaminated with 

 bacteria to allow the slow-growing fungi to develop. Quaker Oat agar 

 is specially suited for determining the presence of the various species 

 of Phytophthora but if any of the Mucorales are present they develop 

 too rapidly and suppress the development of the more slowly-growing 

 species. Cook's agar proved to be an excellent medium for the work. 

 The various organisms, except the species of Phytophthora, develop 

 rapidly and are readily distinguished; pycnidial forms are specially well 

 shown. The Mucorales grow rapidly and if large numbers are present 

 they tend to obscure the other fungi. Modified egg-albumen agar pro- 

 duces a slow growth of all the fungi. It is suitable for careful study and 

 isolation of the various colonies. The plating of the water samples was 

 carried out in the usual manner, special care being taken to cool the 

 melted agars where possible to 45° C, because of the delicacy of some 

 fungus spores. All plates were incubated at 22° C. and examined every 

 24 hours, only the actual parasites being identified. Doubtful organisms 

 were isolated in pure culture and tested for pathogenicity by inoculation. 

 By utilising all four media a reasonably accurate qualitative estimate 

 of the fungus flora of the water sample was obtained. 



In Table I representative water samples are given, and a careful 

 examination appears to justify the conclusion that the water supply 

 may be so seriously contaminated as to constitute an important source 



