340 JACK J. HINMAN, JR., AND MAX LEVINE 



ported in this paper. The B. macerans of Schardinger was isolated 

 in 1904 from potatoes. From the meagre description available, it 

 cannot be differentiated from the strain under discussion. In 1919, 

 Northrop, Ashe and Senior described an acetone producing organism, 

 also isolated from potatoes, which they named B. acetoethylicum. 

 It is said to differ from B. macerans in that the latter does not fer- 

 ment galactose and levulose with NH 3 salts as a source of Nitrogen. 

 We have not been able to obtain cultures of B. macerans or B. 

 acetoethylicum for comparison with our strains. In the published 

 reports the fermentation of lactose (with gas) by B. acetoethylicum 

 is not recorded while B. macerans is said to form gas in milk (presum- 

 ably from lactose) . We will therefore consider our strains tentatively 

 as B. macerans. 



SANITARY SIGNIFICANCE 



Little is known as to the sanitary significance of B. macerans and 

 closely related forms. Such organisms have been isolated from 

 potatoes, retting flax, white flour and water. There is no record 

 that they are present in the intestinal tract although a careful search 

 may disclose them. Information as to the distribution of these 

 sporing, lactose-fermenting forms capable of growing aerobically 

 is now being gathered and the pathogenicity of the isolated strains 

 is also being investigated. The organism isolated by Meyer was 

 non-pathogenic. 



In a chlorinated water B. macerans would be present long after 

 the ordinary water-borne pathogens had been destroyed. The 

 detection of B. macerans, in the absence of organisms of the colon 

 group, in a treated water should therefore not be considered an indi- 

 cation of danger from such intestinal disturbances as typhoid fever 

 or dysentery. The presence of these sporing organisms in water 

 interferes seriously with the routine tests for B. coli with which they 

 may be confused and is possibly responsible for the poor results 

 sometimes reported in water purification. 



SUMMARY 



A Gram negative sporing bacillus capable of fermenting lactose 

 and growing aerobically was isolated from two chlorinated surface 

 water supplies in Iowa. 



The morphological, cultural and physiological characteristics 

 are detailed. 



