AGRICULTURAL BOTANY. 37 



may be drawn because of possible stiuuilation or retardation due to certain 

 conditions. Attention is called to the desirability of studying the conditions 

 which cause the irregularities in the relative transpiration of plants before 

 satisfactory methods for the use of this factor in determining soil fertility can 

 be definitely described. 



Notes on the nature of nitrogen fixation in the root nodules of leguminous 

 plants, J. GoLDiNG (Rpt. Brit. Assoc. Adv. ScL, 1910, pp. 582, 5S3). — "Previous 

 work is summarized, indicating that it is not only the acidity of the root sap, 

 but also the removal of the products of growth, the supply of carbohydrate, and 

 the slime production which must be regulated before artificial cultures of the 

 organism can be expected to fix nitrogen to an extent comparable with that 

 which talies place in the nodule. The ready adaptation of the organism to its 

 environment must also be borne in mind. 



"A new method described and demonstrated for the first time indicates that 

 it is the reaction of the medium which plays an important role in nitrogen 

 fixation. The cultures also disclose previously unobserved properties of the 

 nodule organism." 



On the cooperation and practical value of micro-organisms in the sup- 

 plying of nitrogen of the soil and of the plant, B. Heinze (Jahjcsber. Ver. 

 Angew. Bot., 8 (1910), pp. 29-18, p?s. 2). — The author reviews the present 

 knowlegde of the subject, witli particular reference to the results of his own 

 work previously reported (E. S. R., 24, p. 326). He emphasizes especially 

 the importance of bacteriological studies, particularly as regards the nitrogen 

 supply of the soil, expressing the opinion that the clearing up of tlie question 

 of soil hunuis in its biological relation to nitrogen assimilation is one of the 

 most important, and at the same time one of the most difficult, problems of soil 

 bacteriology. 



Abnormalities of stump growths, G. H. Chapman (Massachusetts Sta. Rpt. 

 1910, pt. 1, pp. I.'i9-160, pis. 2). — A study has been made of various malforma- 

 tions and abnormalities of the lei'.ves of sprouts growing from stumps, with the 

 hope of discovering the cause of these peculiarities and their relationship to 

 other iihysiological diseases. 



The abnormal condition of leaves shown by severe distortion and increase in 

 number as well as size may be classed under the malnutrition diseases, due to 

 functional derangement. It is brought about by conditions somewhat analogous 

 to those i)roduced by excessive use of nitrates or overfeeding, and is not allied 

 to mosaic disease, which it somewhat resembles. The trouble does not appear 

 to be of a permanent character, but seems to be due to an attempt on the part 

 of tlie leaves to correlate their functions with a I'oot area many times larger 

 than normal. 



The clogging of drain tile by roots, G. E, Stone (Massachusetts Sta. Rpt. 

 1910, pt. 2, pp. .'i3--'i6). — Accounts are given of the clogging of drain tile by tree 

 roots, iilgio, etc., and a descrii)tion is given of a pear root that was found to 

 have clogged a 12-in. drain tile. A preliminary account of this has been noted 

 elsewhere (K. S. R.. 25, p. 228). 



Experiments relating to the prevention of the clogging of drain tile by 

 roots, G. E. Stone and G. H. Chapman (Massachusetts Sta. Rpt. 1910, pt. 2, 

 pp. 35--'f2). — The authors have for the past three years carried on experiments 

 to study the effects of various antiseptic substances in preventing roots of dif- 

 ferent kinds from entering drain tile. In one series of experiments tiles were 

 inserted in boxes and the .joints calked with antiseptically treated fibers, in 

 the second the bottoms of pots in which plants were grown were filled with 

 chemically treated fibers of various kinds, and in the third series boxes were 



