ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 101 



(1) In the normal plant the full exercise of its functions of growth 

 and a normal histological condition occur vvhen potash and chlorine 

 are relatively in excess, and lime is relatively wanting. (2) In the 

 diseased plant the imperfect nutrition and distribution of the reserve- 

 products, as also modifications of the cellular structure, are associated 

 with deficiency of potash and chlorine, and excess of lime. Chemical 

 analyses show that when the restoration from abnormal to normal 

 functional activity occurs, the chemical constituents change their 

 relations to those observed in healthy trees, i. e. the potash increases 

 in proportion to the lime. 



Food-material of the Ling.* — The ling, Calluna vulgaris, being a 

 plant remarkable for its indifference to condition of climate, altitude, 

 and soil, MM. P. Fliche and L. Grandeau have made a series of 

 observations on the composition of the ash, which they found re- 

 markably constant under varying conditions of soil. It is essenti- 

 ally a calcifugal plant, but is indifferent to the chemical composition 

 of the soil, provided it does not contain too much lime. Eequiring a 

 very small quantity of matter derived from the soil, it will flourish 

 on jjoor land, where scarcely anything else will thrive. 



Products of Assimilation of the Leaves of Angiosperms-f — 

 Herr A. Meyer has carried on a series of experiments for the purpose 

 of determining the question : In what chemical form is the assimilated 

 carbon chiefly stored up in the assimilating cells? Although un- 

 doubtedly far the larger part is in the form of carbohydrates, yet there 

 is nothing in the results obtained to show that a portion of it may not 

 be transitorily stored up in the form of proteids. It may also occur 

 in the form of fatty oils, though this is not very common, as these 

 substances are not as such capable of carriage from cell to cell. 



Herr Meyer demonstrated by experiment the power of leaves to 

 form starch out of sugar, even in absolute darkness, and of the non- 

 assimilating cells in young leaves to receive starch from the other 

 organs. As to the particular carbohydrate present in the leaves, he 

 found that, as a general rule, dicotyledons store up a large quantity 

 of starch, monocotyledons much less. 



He then enters into a very interesting discussion as to the relative 

 size of the molecules of the different carbohydrates. Of the glucoses 

 he concludes that dextrose or grape-sugar, levulose or fruit-sugar, and 

 lactose or galactose, have the smallest molecules of all the carbo- 

 hydrates ; probably they have all the same formula, Cg H,2 Og. Cane- 

 sugar must have a molecule about twice as large as that of glucose, 

 probably C,2Ho2 0n, since it can be split up by invertin or by dilute 

 acids into dextrose and levulose. Of nearly the same composition as 

 cane-sugar are gentianose and the rare melezitose and melitose, less 

 certainly also levulin. Lactosin and inulin form a group which must 

 have a molecule at least six times the weight, viz. GCe H|o O5. To 

 the same group probably belong also triticin and galactin, if these are 



* Ann. Sci. Agronomiques, 1885. See Bull. Soc. Bot. France, xxxii. (1885). 

 Kev. Bibl., p. 78. 



t Bot. Ztg., xliii. (1885) pp. 417-23, 433-40, 449-57, 465-72, 481-91 497-507. 



