1894. ] Anatomical and Physiological Researches. 285 
The importance of algal assimilation, for so long a time over- 
looked, is by no means inconsiderable, for it doubtless will 
enable one to harmonize many results that heretofore seemed 
inexplicable. Particularly is this true with experiments car- 
ried on in natural soils with non-leguminous phanerogams, 
where the nitrogen claimed to be assimilated is always rela- 
tively small. 4 f 
In regard to chlorophylless organisms, Berthelot * has 
recently studied several soil bacteria in pure culture, Asper- 
gillus niger, Altenaria tenuis, and a Gymnoascus, using for 
a culture medium, humic acid and kaolin. With these 
forms he was able to detect a marked increase in the nitro- 
gen content. The bateria of lupine tubercles grown in humic 
acid and Cohn’s solution increased the amount of fixed nitro- 
gen by fifty per cent. He also noted that when the amount 
of combined nitrogen becomes large, the organisms utilize 
this rather than continue to fix the elemental gas. 
Winogradsky ° has issued a preliminary paper upon the 
ability of bacteria to function as nitrogen collectors. He 
worked under bacteriological conditions, using for a culture 
medium a non-nitrogenous but fermentable solution (pure 
dextrin and specially prepared mineral salts). With this 
medium, he isolated one well characterized bacillus able to 
form gas and produce butyric acid in quantities. It would 
grow neither on gelatin nor on gelatinized silica to which 
Sugar had been added. In general, it bore a strong resem- 
blance to Fitz’s B. butylicus. 
While the evidence at hand as to the ability of lower or- 
fanisms to utilize atmospheric nitrogen seems to be fairly 
complete, it is not so definitely settled whether the same 1s 
true for higher plants, excluding of course the legumes. 
Frank has persistently maintained the view that the ability 
* fixing nitrogen was a function of protoplasm and was resi- 
dent in the higher plants as well as the simpler. Especially 
is this marked, he claims, in thrifty, vigorous plants in the 
Srowth subsequent to the seedling stage. He has found, re- 
Peatedly, a marked increase in the nitrogen content of soil 
and crop where non-leguminous plants such as rape, oats and 
po Sa which a fixation of .N was observed with oats, cress 
be 4 Sal vegetation flourished, but where this was excluded no gain 
4 etected. 
Comptes rendus Acad. 116: 842. 189 
s : 
Comptes rendus Acad. 116: 1385 3- 
189 
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