126 MAINE AGRICULTURAL EXPERIMENT STATION. 



Sola-num tuberosum (4 pes.) — grams of nitrogen in seed 0.022; 

 in crop, 0.2186. 



Another experiment with Sinapis alba detailed in the same 

 paper, also indicated a certain amount of nitrogen fixed. These 

 results with mustard were apparently confirmed by Liebscher,* 

 but in both cases the methods of analysis were lacking in accu- 

 racy and the factors of growth were not carefully controlled. 



Lotsyf in 1893, after a very careful study of the subject, using 

 both sand and water cultures in sterilized and unsterilized con- 

 ditions, asserts positively that neither Sinapis alba nor 5". nigra 

 are able to live without combined nitrogen. Schloesing and 

 Laurent have also showni that white mustard, oats, cress and 

 spergula were unable to assimilate free nitrogen. 



In 1890, Petermann§ announced that barley was as efficient 

 as beans in collecting nitrogen. After repeating his experi- 

 ments, however, under more careful control, he was obliged to 

 retract. r 



In 1893, Frank,** in summarizing the results of his experi- 

 ments, repeated his assertion that, "the non-leguminous organ- 

 isms can assimilate free nitrogen," and cites examples of fungi, 

 algae and mosses, as well as oats, buckwheat, spurn-, turnip, 

 white mustard, potato and maple. 



Xobbe and Hiltneryf conducted a series of experiments with 

 mustard. The plants were grown in sand to which varying 

 amounts of nitrogen were added from time to time. The total 

 yield of nitrogen kept pace with the varying amounts of soil 

 nitrogen, but there was no increase due to assimilation of free 

 fiitrogen. 



In another experiment!:: with peas, mustard, buckwheat, and 

 oats, it was found that the peas alone were able to acquire the 

 nitrogen of the air, while the others showed a decline in spite 

 ot the increased amount of nitrogen in the soil. 



Frank's discovery that certain algae are able to utilize uncom- 

 bined nitrogen has been repeatedly confirmed by Schloesing 



*Jour. f Land-sv. 41 : ISO (1893). 



-Bui. 18, O. E. S., U. S. Dept. Of AgT. 



;Ann. Inst. Past. 6: 114 (1892). 



5 Mem. Acad. Roy. de Belg. 44: 1889. 



•"Bui. Acad. Roy. de Belg. 25: 267-276, 1893. 



**Bot. Ztg. 51: 139 (1893). 



tfLandw. Vers. Stat. 45 (1894), 155-159. 



Qltrid. 



