824 EXPERIMENT STATION EECORD. 



account of the results obtained by the author from experiments with chloroform 

 and ether on Spirogyra and Tradescantia discolor as exhibited by their absorp- 

 tion of coloring matters. 



In the case of Spirogyra, the narcotized portions showed decidedly less per- 

 meability than did the normal portions of the same threads. Experiments with 

 Tradescantia were held to show that the iTermeability of sodium nitrate (which 

 is easily soluble in water, but sparingly so in chloroform and ether) is lessened 

 by narcosis. The author claims that the decrease in permeability of plasma 

 membranes by narcosis tends to support a hypothesis previously advanced by 

 him that in the medium of the plasma membrane fatty bodies— perhaps lecithin 

 and cholesterin — are to be found; also, that the manner of diffusion of salts 

 and other bodies easily soluble in water is similar to that of anesthetics. 



On the phototropic results of bilateral illumination, O. Hagem {Bergens 

 Mus. Aarholc 1911, No. 1, Art. 3, pp. 1-lS, pi. 1, fjfis. 3).— This is a study along 

 lines already marked out by Wiesner of the positions taken by plants illumi- 

 nated from 2 directions. The principal findings are as follows : 



Bilaterally illuminated seedlings tend to place themselves so that their curves 

 lie in the vertical plane of the resultants of the 2 light intensities. This posi- 

 tion can be calculated by graphical representation of the intensities as forces. 

 The amount of their curvature appears to depend upon the value of such result- 

 ant. Experimental results conform closely to theoretical values. 



Contributions on the morphology and biology of the tubercle bacteria of 

 legumes, H. Zipfel (Oentbl. Bakt. [etc.], 2. AM., 32 {1911), No. 3-5, pp. 97- 

 iS7), —Besides noticing briefly the conclusions of other investigators in this con- 

 nection, the author gives the results of his owm researches, some of which may 

 be stated as follows : 



The bacteria of the root nodules of legumes will thrive in cultures of legume 

 decoction, or in weak solutions of animal or vegetable albumin. They are not 

 very sensitive to the reaction of the culture medium, which may vary from 

 weakly acid to slightly alkaline without checking their growth. The zone of 

 optimum temperature is between 18 and 20° C. ; the limits of growth are 3 and 

 45° ; and the upper limit of life is from 60 to 62°. They are not pathogenic as 

 regards animals and are claimed to be not simple varieties of one species 

 but of several distinct species the relationships of which are not yet clearly 



ascertained. 



The assimilation of atmospheric nitrogen through thermophilous bacteria, 

 H. Pringsheim (Centbl. Bakt. {etc.], 2. AM., 31 {1911), No. 1-4, pp. 23-27).— 

 The author claims that the heat-loving bacteria isolated by him were able to fix 

 atmospheric nitrogen in considerable quantities, employing glucose as a source 

 of necessary energy, but only when to the Winogradsky culture medium was 

 added a decoction of soil, although what part this latter plays he did not ascer- 

 tain. He reports also, as in his previous experiments (E. S. R., 23, p. 30), to 

 have found that the lower concentration of glucose seemed to favor the higher 

 utilization of energy material. It was strikingly noticeable that the fermen- 

 tation and accompanying assimilation of nitrogen by the thermophiles proceeded 

 much more rapidly than in the case of the anaerobic nitrogen-fixing bacteria. 



Nitrogen compounds in growing mustard, Densch (Mitt. Kaiser Wilhelms 

 Inst. Landw. Bromherg, 3 {1911), No. 5, pp. 387-393).— K report of a quantita- 

 tive study of the several compounds of nitrogen present in mustard during its 

 growth, and preliminary to a contemplated more general study of nitrogen trans- 

 formations in cultivated plants. 



The behavior of Pseudomonas radicicola in the soil, B. M. Duggae and 

 M. J. Pbtjcha {Ahs. in Science, n. ser., 35 {1912), No. 893, p. 229).— A prelimi- 

 nary report is given showing the effects of conditions, especially drying, on the 



