I02 



in the absence of glucose there is but a slight assimilation of this 

 element by algae. 



Neither in the presence nor in the absence of glucose or of 

 mannite did fixation occur when urea, glycocoll, asparagin or 

 ammonium sulphate was supplied as the source of nitrogen. 



All of these experiments on green algae confirm the old in- 

 vestigations of Frank (7), who cultivated many species of 

 Chlorophyceae, first in unsterilized media, then in sterilized 

 media free from nitrogenous compounds, reaching the conclusion 

 that algae assimilate the free nitrogen of the atmosphere. 

 Identical results were obtained at the same time by Gautier and 

 Drouin(8). 



The most recent work published on the assimilation of free 

 nitrogen is that of C. B. Lipmann and J. K. Taylor (9). These 

 authors cultivated wheat plants in nutrient solutions, either 

 without nitrogen or containing nitrogenous compounds. In 

 both cases these solutions were so prepared as to have approxi- 

 mately the same concentration throughout , regardless of whether 

 or not nitrogen was present. In the case of the solution con- 

 taining no nitrogen, twelve jars were employed, six of them being 

 kept in the greenhouse until seeds were formed. AH of the other 

 plants were grown for a period of six weeks only. At the end of 

 the experiment, the authors found that all of the plants had 

 assimilated nitrogen from the air in quantities varying from 13 

 to 2 1 per cent of the total amount of nitrogen found in the plant. 



The publication in question is of a preliminary' nature in which 

 many details are lacking, and the authors do not state whether 

 or not the cultures were sterile, but it is to be presumed that they 

 were, as otherwise the work would be of much less interest. 

 The authors announce that they also have cultures of barley^ 

 legumes, etc., under experimentation which promise to yield 

 similar results to those obtained with wheat. 



The authors of this interesting work, who are well known in 

 the scientific world for their competence in matters relating to 

 agricultural physiology, express in conclusion the following 

 opinion: 



"There can be no question now, however, that the teachings 

 of all our books and nearly all our teachers of the subject to-day 

 are erroneous and must be changed completely to accord with 

 the facts presented by us, and by the other investigators whom 



