BOTANY. 421 



The acidity of the stems was foiiiul to ))e diminished from the summit downwards. 

 The acidity of the leaves, which is much greater than that of the stem, is in inverse 

 proportion to the age of the leaves, young leaves being the more acid. Within a 

 given leaf the acidity is greatest near the zone of growth. In the flowers the acidity 

 decreases from the bud to the fully expanded flower. In all the investigations the 

 younger i)arts were found to possess the greatest acidity. 



A simple method for demonstrating the translocation of starch, S. 31. B.vin 

 (Univ. Tennessee Becord, 5 {1902), No. 4, jyp- 2.59-262, jirjs. S). — While engaged in 

 studies on the effect of fungicides on the foliage of peach, plum, etc., the auth )r 

 found that by placing a number of small drops of a 3 per cent solution of copper sul- 

 phate upon the mature leaves of plums or peaches, if the leaves are allowed to remain 

 attached to the stem until the dead areas begin to drop out, the translocation of the 

 starch may be shown. The specimens should be put into alcohol on successive days 

 from the time of the a^jplication until the dead areas are (;onspicuous, and examined 

 in cross section under the microscope, using Schulze's solution for staining. Tt will 

 be noticed that rapid cell division has occurred at the healed margin, and by the 

 application of iodin distinct zones of starch accumulation will be readily discovered. 



Testing for mannose, F. H. Stoker {Bvl. Bu>isey Inst., 3 [1902), II, pp. 1.3-45). — 

 The author reports the presence of mannan in the trunk of sugar maple trees, espe- 

 cially in the wood of trees which were felled during the winter months. After the 

 formation of the leaves has begun the amount of mannan present rapidly diminishes 

 to a minimum. It is evident from the investigations reported that mannan is stored 

 as a reserve food in the wood of the sugar maple. Negative results were obtained in 

 testing the wood of the gray birch, poplar, and willow for this substance. It was 

 found present in the orange peel, but not in the seeds, and occurs in a small quantity 

 in the tuberous roots of the Jerusalem artichoke in connection with inulin. Mannan 

 was found present as an adjunct to starch in the seeds of the horse chestnut and also in 

 the storage roots of chicory, dandelion, and asparagus. Although the wood of the 

 white pine and Norway spruce contain mannan in abundance, it was almost totally 

 absent from the seeds of these trees. The author believes that in regard to wood of 

 trees, other substances wall be found comparable to starch and mannan which serve 

 as reserve food for the production of leaves and new wood in the spring. Detailed 

 directions are given for the testing and identification of this suljstance. 



The effect of acetylene gaslight on plant growth, F. W. Raxe {Ahs. in Science, 

 n. ser., 16 {1902), Xo. 395, p. 137). — According to the author, acetylene gaslight has a 

 marked effect upon plant growth, esjiecially upon plants grown under glass during 

 the winter months. Experiments showed that some plants were more influenced 

 than others by the stimulation of the light. 



Concerning the specific individuality of the root-tubercle bacteria of legum- 

 inous plants and the agricultural significance of the question, H. Buhlert 

 {Fuhlincfs Landw. Ztg., 51 {1902), Nos. 11, j)p. 385-391; 12, pp. 417-427).— kn account 

 is given of experiments in which peas and beans were inoculated with organisms 

 taken from tubercles found on the roots of peas, beans, horse beans, and Acacia spe- 

 ciosa. The seeds were sterilized in 0.2 per cent solution of corrosive sublimate and 

 grown in sterilized quartz sand, watered with distilled water, and fertilized with 

 phosphoric acid, kainit, and lime. All the organisms were cultivated in pure cultures 

 which served for inoculation material. The author concludes that all the organisms 

 are forms of Bacillus radicicola. The bacteria best adapted to a given species of 

 leguminous plant are those naturally found upon that plant. Inoculation with bac- 

 teria is possible within certain limits, and while pure cultures are desirable, yet, on 

 account of the difficulties connected with the obtaining and use of such materials, it 

 will generally be found best in agricultural practice to depend upon soil inoculation. 



The fixation of nitrogen by leguminous plants, T. Remy ( Chem. Ztg. , 26 { 1902), 

 JV'o. SO, pp, 945, 946) . — A brief discussion of some of the principal results of recent 

 investigations on this subject. 



