946 EXPEEIMENT STATION EECORD. 



pU. 4, figf<. 5). — A l3rief review is given of tlie field trials with Nitragin prior to 1900, 

 and the tests for that and the succeeding year are reported upon at considerable 

 lengtli. Of the tests conducted in various parts of the country during 1901 it is 

 claimed that 54 per cent of all reported gave very favorable results. The experi- 

 ments conducted at the Dahlem Station under the authors' direction gave almost 

 uniformly increased growth when inoculated with pure cultures. Experiments were 

 made in which the relative efficiency of treating the seed and the soil with solutions 

 containing pure cultures was compared. A number of laboratory experiments are 

 reported showing the effect of various factors on the development of root tubercles. 

 Among the factors studied were the influence of the materials found in the endo- 

 sperm of the seed; effect of grape sugar; various nitrogenous su))stances, such as salt- 

 peter, asparagin, ])eptone, and combinations of these sul)stances with grape sugar; 

 the effect of phosphoric acid used alone and in combination with other substances; 

 and effect of organic acids, etc., upon the root-tubercle organism. The value of pure 

 cultures of the physiologically specialized organisms is also reported upon at consid- 

 erable length. The paper concludes with some brief references to the investigations 

 conducted during 1902 l)y the authors on the perfection of methods of inoculation. 



Observations on some algae causing "water bloom," N. P. B. Nelson [M'm- 

 nesota Bot. Studies, 3. ser., 1903, pt. 1, pp. 51-50, pi. 1). — On account of the sanitary 

 importance of some algfe in the sources of water supply the author has made a study 

 of the species which produce the condition known as "water ]>loom" in a number 

 of localities in Minnesota. So far as known there is no record of the occurrence of any 

 of these injurious algse to any great extent in the rivers or lakes supplying drinking 

 water to the cities and towns of the State, but in several instances the death of cattle 

 and other animals has been attributed to the presence of these organisms. As a result 

 of the author's investigations 7 species of blue-green algfe which form water bloom are 

 known to occur in the State, the species being as follows: GlardrieJiia p>is<.wm, Ccelos- 

 phivrium kuetzingianum, ApJianizomenon floH-aquic, Clathrocijstis a?rnginn.<<a, Annhena 

 circindlis, A. flos-aqmv, and A. mendoUe (?). In several instances it has been almost 

 conclusively proved that the presence of one or more of these sjaecies in drinking 

 water used by stock has caused fatal results. 



The suspension of life at low temperatures, A. Macpadyen and S. Rowland 

 {Ann. Bot., 16 {1902), No. 64, pp. 589, 590). — An abstract is given of a paper pre- 

 sented by the authors before the British Association for the Advancement of Science, 

 showing the results of experiments with various bacteria and other organisms, when 

 subjected to the temperature of liquid air and licjuid hydrogen. Altogether 10 

 organisms were cooled to a temperature of —190° C. for 7 days without producing any 

 appreciable depreciation of their vitality either as to their growth or their other 

 physiological or pathogenic properties. Later the organisms were subjected to 

 temperatures of —252° C. by means of liquid hydrogen. In this case a number of 

 different pathogenic and other organisms were subjected to this temperature for 

 a period of 6 months and in no case was any reduction in the vitality of the 

 organisms detected. After this period of subjection to low temperatures yeasts gave 

 good growth and exhibited unaltered powers of fermentation. Typhoid bacillus 

 retained its pathogenic and other properties while the other bacteria responded to 

 the various tests applied to them. It appears that the ordinary manifestations of 

 life cease at zero, but at —190° C. it is believed that even intracellular metabolism 

 ceases as a result of the withdrawal of all heat and moisture from the organism. 



The necessary presence of bacteria in cultures of Myxomycetes, Pinoy 

 {Bui. Soc. Mycol. France, 18 {1902), No. 3, pp. ^88, 289; abs. in Bot. Centbl., 90 {1902), 

 No. 11, p. 303). — The author claims that it is nearly, if not quite, impossible to secure 

 cultures of many Myxomycetes in pure media, but when the cultures are mixed in 

 the presence of Bacilhis Inteus he has been able to successfully grow various stages of 

 Didymium effusuni and other forms. 



