No. 6. DEPARTMENT OF AGRICULTURE. 33* 



that the latter possessed a polymorphic habit never before imagined 

 in this or any other like group in the whole domain of mycology. 

 The ability of simple eoccoid or rod-shaped forms to develop into 

 filaments or even into branched forms, with the further production of 

 true gonidia and other even more highly organized fructification 

 bodies, is a species of morphological transcendentalism likely to 

 cause skepticism. 



I will not enter into the details of Stutzer and Hartleb's investi- 

 gations, as I think we should await further researches before giving 

 them credence. It is easy to believe that the latters culture, which 

 they claimed to be those of the organism of nitrification, were in 

 reality impure, and that in the variable forms described by them they 

 were in reality dealing with several distinct organisms instead of one. 



That this seems true is indicated by the investigations of Gartner^^ 

 and Fraenkel^- during the present year. 



Gartner discusses 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 micro-organisms, including a fungus form (Schimmelpilz); 

 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 II different organisms, 

 including 7 bacilli, 2 streptothrices and 2 fungi (a Fadenpilz and a 

 Schimmelpilz). These showed no polymorphism, but all retained 

 constant characters. 



From what has been written there is reason to believe: 



1. That nitrification in the soil is caused by a distinct or rather by 

 two distinct organisms possessing certain definite characters. 



2. That these organisms will not grow in the presence of any con- 

 siderable amount of organic matter, and that all reported attempts 

 to cultivate them on ordinary organic media are without authentica- 

 tion. 



3. That the above nitrifying organisms are found abundantly in. 

 all cultivated soils, and that in ordinary soil water containing, be- 

 sides mineral salts, a due proportion of ammonium carbonate, sul- 

 phate, etc., they find a favorable medium for their development. 



4. That the result of such development is: (a) The conversion of 

 ammonia into nitrous acids through the agency of the nitrous organ- 

 ism; and (b), the immediate conversion of the previous nitrous into 

 nitric acid by means of the equally abundant nitric ferment. 



Understanding, therefore, that these two stages of nitrification are 



