AGRICULTURAL BOTANY. 1145 



serves for the synthesis of albumin and the oxalic acid, precipitated by the calcium, 

 remains without further influence, If this hypothesis were true, in the absence of 

 calcium Baits the oxalic acid formed would not be neutralized, and, being injurious 

 to plants even in small quantities, would hinder the assimilation of the nitrate 

 nitrogen. 



To determine this Bubjecl the author carried oul '■> scries of experiments with 

 leaves of grapes, Paulownia imperialis, and Ailanthus glandulosa. In these experi- 

 ments the author used one side of the leaves of grapes and Paulownia and the leaf- 

 lets on one side of the raehis of A ilant hns, the other portions remaining a- a cheek. 



The nitrate nitrogen was determined by the Schultze-Tiemann method. 



In the first series of experiments some <>f the leaves were placed \<>v L'l hours in a 

 0.2 per cent solution of calcium nitrate ami others in a ill' per cent solution of potas- 

 sium nitrate. At the end of the experiments only traces of nitrate nitrogen were 

 found in the leaves receiving the calcium solution, while the leaves placed in the 

 potassium solution contained an appreciable quantity of nitrate nitrogen. This 

 seems to indicate that in the leaves receiving calcium the nitrate was consumed by 

 the plaid. 



In the second series of experiments the leaves were placed in a 0.2 per cent solu- 

 tion of potassium nitrate ami were then cut in halves, some of which were used as 

 controls while others were placed in various solutions. The results show that in the 

 leaves which had received calcium salts the nitrate disappeared, being assimilated, 

 while where no calcium salt was present the nitrate remained unaffected. The 

 author concludes from this that calcium is indispensable for the assimilation of 

 nitrate nitrogen. — p. fireman. 



The morphology and biology of nitrogen-assimilating organisms, J.. Lrrz 

 (/,-.-• microorganismes fixaleurs d'azote. Paris: ./. Lechevalier, 1904, i>i>- 187, figs. i'<; 

 abs. In Cenibl. Bakt. [etc.'], 2. AbL, 15 I 1905), No. 15-16, />/>. ;;;, 478).— The author 

 gives a critical review of the literature relating to nitrogen assimilation by bacteria 

 and other micro-organisms and practically givesa summary of the present Btatus of 

 knowledge on the morphology and biology of nitrogen-assimilating organisms. 



After a historical resume, the author gives an account of the attempts to cultivate 

 tin- nitrogen-fixing organisms, particularly the experiments of \Vino<_ r radski and 

 Beijerinck, and of the cultures known as Alinit. The general conditions for fixation 

 of nitrogen in the soil and factors limiting it are described, after which especial 

 attention is given the morphology and physiology of the tubercles on the roots of 

 the Leguminosse and of the organisms which they contain. The literature on the 

 culture of these organisms is reviewed at considerable length, and suggestions are given 

 for the growth of the bacteria in nitrogen-containing and nitrogen-free media. The 

 biological forms and physiological characteristics oi the organisms are described and 

 the various factors controlling nitrogen assimilation are reviewed. Accounts are 

 given of various attempts in the utilization of the bacteria by applying them to 

 practical use in the Held, particularly on the use of pure cultures. 



In addition t<> the Leguminosse the author shows that tubercles ot a Bimilar nature 

 occur on the toots of alders, Eleagnus, Podocarpus, Myrica, Datisca, etc. 



A chapter is devoted to the fixation <>f free atmospheric nitrogen through sym- 

 biosis between algae and bacteria by mo>v ( . s . etc. 



An extended bibliography oi literature completes the volume, about ">l><> titles 

 being cited. 



Effect of differences in solar radiations on the transfer of albuminoids in 

 wheat, .1. Dumont {CompL Rend. .!"/</. Sci. [Paris], I'd [1905), No. is, pp. 686- 

 66'8).~ It having been claimed that light is necessary for the formation of albumi- 

 noids in plants and that the more refrangible rays are most active in this respect, the 

 author investigated the subject and reports experiments carried <>n during 2 different 



