216 NITRIFICATION 



According to Kaserer there is an organism which can oxidize 

 ammonia direct to nitric acid, but so far this has not been confirmed. 



In 1892 Winogradsky studied the nitrifying organisms of the 

 soil from a number of different localities. Those from several 

 parts of Europe, from Africa, and from Japan, which he considers 

 to be the same organism, he names Nitrosomonas europea. A second 

 form from Java soil differing from the first, he names Nitrosomonas 

 javenensis. Both of these comprise the nitrate ferments of Wino- 

 gradsky, the second nitrate ferment was isolated by Winogradsky 

 from Quito soil and differs from the first not only as to size, as 

 above mentioned, but also by entirely lacking the motility common 

 to the latter. 



In 1895 Burri and Stutzer isolated from soil a nitrate organism 

 with properties akin to the Quito bacillus of Winogradsky. It was 

 a motile organism, 0.75 - - 1.5 x 0.5 micromillimeters, growing 

 on gelatin which it liquefied, said organism, according to these 

 workers, being able to convert nitrites into nitrates, but losing 

 such power when grown on organic media. 



The results of Burri and Stutzer, so contrary to those of Wino- 

 gradsky, brought forth a vigorous rejoinder from the latter. In 

 this Winogradsky stated that he tested the same earth used by 

 Burri and Stutzer and isolated therefrom his own nitrosomonas, and 

 that the latter when tested in bouillon, meat peptone, gelatin, and 

 agar failed to grow. He, therefore, regards the German work as 

 erroneous. 



In 1897 Stutzer and Hartleb appeared with a still more startling 

 series of discoveries in which they not only maintained the ability 

 of the nitrifying organisms to grow in organic media, but also 

 showed that the latter possessed a polymorphic habit never imag- 

 ined in this or any other like group in the whole domain of mycol- 

 ogythe ability of simple coccoid or rod-shaped forms to develop 

 into filaments or even into branched forms, with the further pro- 

 duction of true gonidia and other even more highly organized 

 fructification bodies. 



Gartner discussed the work of Burri, Stutzer and Hartleb on the 

 polymorphism of the nitrifying organism, and from presumably 

 pure cultures of the latter's nitrifying ferment was able to isolate 

 thirteen different microorganisms, including a fungus form (Schim- 

 melpilz), thus proving their impure character. Furthermore, 

 Gartner showed that these several organisms, when once separated 

 in their pure state, retained their fixed character, with no tendency 

 to polymorphism, and indicated none of those transition stages 

 from bacteria to fungi noted by Stutzer. Again, none of these 

 isolated organisms possessed the power to convert ammonia into 

 nitrites. C. Fraenkel simultaneously isolated from Burri and 

 Stutzer's cultures 11 different organisms, including 7 bacilli 



