改良魯桑

市平

多胡早生種

桑苗

採葉

(the experimental total volume of the bundle) = the practical specific gravity. 3) As a method to test the strength of the stems of the mulberry trees with a view to experimentally testing their durability when bent with our hands, we made an instrument for this purpose. First we fixed the both ends of a stem to the instrument, them we moved forward one end of the instrument, and measured the distance traversed by this one end of the instrument in its motion until the stem was bent and broken. The distance thus measured we termed the breaking strength of the mulberry stem. Each specimen was tested in this manner. The following equation shows the calculation of what we termed the "Estimating factor":? (the length of the stem used for estimation)

(the area of the cross section of the stem) = FK. In the estimation, we used the diameter, instead of the area, of the cross section of the stein, and used the following formula as the experimental length of the stem in the estimation of the breaking strength:? The diameter of the stem x Fk. 4) The length of the stem and the weight of the mulberry trees became shorter and ligher respectively than the "control" in proportion to defoliation and the repetition of defoliation. Generally, the internodes became small; the diameter, the specific gravity, and the breaking strength of the stem became small; the ratio between the diameter of the pith and the diameter of the stem, and also the parts that winterkill became larger than the "control" in proportion to defoliation and the repetition of defoliation. This was true of all the varieties of mulberry trees we studied. 5) The water and the ash contained increased, and, consequently, the dry matters and the organic matters decreased in propotion to defoliation and the repetition of defoliation. This was true of all the varieties of mulberry trees we studied. 6) The nitrogen compounds, such as the total nitrogen, the albuminoid nitrogen, the non-albuminoid nitrogen, and, among the non-albuminoid nitrogen, the nitrogen precipitated with phosphotungstic acid, etc. decreased in the day and fresh matters in proportion to defoliation. 7) In the case of the carbohydrates, the total carbohydrates converted by dilute hydrochloric acid decreased in proportion to defoliation. Of these, the cold water soluble carbohydrates, the reducing sugars, etc., that is to say, the sugars that form most part of them, showed, a tendency similar to the total carbohydrates converted by dilute hydrochloric acid in the roots in which nutrients are preserved. In the stem, however, the cold water soluble carbohydrates showed no appreciable change, but the reducing sugars tended contrary to the total carbohydrates, converted by dilute hydrochloric acid, except, generally, when defoliation had been repeated three times. Consequently, the higher class carbohydrates, that is to say, the preserved carbohydrates that form of most part of them, decreased largely, as compared with the "control," even in the stem, in proportion to defoliation. 8) The increase of the water and the ash, that is to say, the decreased of the dry matters and the organic matters respectively, and also the decrease of the total carbohydrates converted by dilute hydrochloric acid, were larger in the the roots than in the stem in proportion to defoliation. 9) In proportion to defoliation, the mulberry trees became inferior not only in external forms and in weight, but in their physical properties and contents of chemical constituents. 10) In the case of the mulberry trees defoliated once for the August silkwarm culture on the 15th of August, that is, the period of the most vigorous growth in length of the mulberry trees, the outward forms, that is, the length of the mulberry trees, the outward forms, that is, the length of the stems, their diameters, etc, and also their .absolute weight became shorter and lighter respectively than the "control." There was little winterkilling, and the specific gravity, the breaking strength, and the contents of chemical constituents in the dry and the, fresh matters, generally showed no appreciable difference as compared with the "control." In the case of the mulberry trees defoliated once for the September culture on the 15th of September, that is, the season in which the mulberry trees are usually most active for the accumulation of nutrients, the outward forms, that is, the length of the stems, their diameters, etc. and also their weight generally showed no appreciable difference as compared with the "control," the defoliation in this season not impeding the growth of the trees in length. But the ratio between the diameter of the pith and the diameter of the stem, and also the parts that winterkill became larger than the "control." The physical properties and the contents of chemical constituents became inferior, and the preserved nutrients generally decreased in proportion to defoliation is this season. 11) Although the mulberry trees defoliated once for the September silkwarm culture showed no appreciable difference in form and weight, that is, in outward appearance, as compared with the "control," their real value was found to be greatly impaired by defoliation.

1, 改良鼠返, 改良魯桑, 市平, 多胡早生種につき育苗中採葉したる場合桑苗に及ぼす理化學的影響につきて研究せり。2, 比重の測定は枝條を2糎宛の切片としたるものを細絹絲にて束ねて計騷圓筒中の水中に細針金にて上より押し沈めて知り得たる實驗的の枝條切片全容積にて重量を除し其の商を以て比較比重を表せり。3, 枝條の張さを見る一方法として兩手にて枝折る場合の耐久力を實驗的に見んとし, 之に用ふべき測定器を作製し, 枝條の兩端を測定器に固定し, 測定器の一方を前進移動せしむる時に枝條が彎曲切斷する迄に要したる移動距離を測定し其の歎値を比較試驗し枝條の折の強さと命名せり。且つ測定に當りては…………(測定に供すべき枝條の長さ)