SPORE-FORMING ORGANISM FROM IOWA 



331 



From two sources, Iowa City and Burlington, Iowa, 14 pure cul- 

 tures have been isolated and studied as to their morphological, 

 cultural and other characteristics. Considerable difficulty was en- 

 countered in effecting separation from non-fermenting, sporing 



TABLE 1 

 Fermentation tests on treated Iowa city waters, March 3, 1914, t December SO, 1920 



Total number of fermentation tubes 10,566 



Total number positive 2,378 



Total number positive, non-confirming 1,902 



Per cent positive tubes non-confirming 80 per cent 



Per cent all tubes non-confirming positive 18 per cent 



Burlington, Iowa City, Keokuk: 



Per cent positive tubes non-confirming 85 .3 per cent 



Per cent all tubes non-confirming positive 17 per cent 



aerobes, which seemed to grow associatively. The method which 

 proved most successful was (1) to grow in lactose (Andrade) broth, 

 (2) to plate on lactose (Andrade) agar as soon as acid developed, (3) 

 fish acid colonies to lactose (Andrade) agar slants (inoculate sur- 



