Noteworthy anatomical and physiological researches. 
The fixation of free nitrogen by plants. 
A review of the question of the assimilation of free nitro- 
gen must of necessity be somewhat disconnected as different 
investigators approach the subject from such different stand- 
points, some dealing entirely with the economic phase while 
others treat its biological aspect. 
The present synopsis deals mainly with the literature of 
the year 1893, including only those papers of the previous 
year that throw light upon concluding investigations. 
Research on this question has not been as active during 
the past year as in preceding years, and in a number of cases 
papers are only concluding pieces of work undertaken earlier. 
The general trend of the whole subject, broadly considered, 
has been much more in the line of general physiological exper- 
iment than in the morphological study of the agent of nitro- 
gen fixation. 
Assimilation by non-leguminous plant organisms. 
Concerning the question as to what organisms are able to 
utilize uncombined nitrogen, several papers have appeared. 
rank’s contribution to the subject in showing that some 
of the alge possess this ability seems now to be — 
beyond dispute. Schloesing and Laurent? experiner 
upon this question, using both the direct and indirect meth- 
ods of nitrogen determination and found that not only ha 
the green alge able to fix gaseous nitrogen but that some be 
the mosses possessed this peculiarity in a marked nee 
Koch and Kossowitsch ? have repeated this work with gree f 
and blue green alge, using purely inorganic solutions an 
have arrived at the same conclusion. While the nu 
experiments upon this point seem to show conclusively et 
the lower green forms of vegetable life possess this pow? 
yet it would seem desirable if experiments were also er " 
out with pure cultures of various forms and thus pee es 
exclude all possible chance for misinterpretation of FAN 
a ag Inst. Past. 6: 110. 1892.-Comptes rendus Acad. 115: 732. 1892. j 
ot. Ztg. 51: 342. 1893. é approx” 
_ > Some of Schleesing .and Laurent’s experiments were carried out oD 
imately pure species but they were not grown in sterilized culture media. 
