152 Scientific Intelligence. 



demonstrated that root tubercles are not produced by only one 

 species of bacterium, varying, as some have thought, according 

 to the kind of soil in which they occur. 



Although much advance has been made in the direction of 

 settling some of these disputed points, a great deal remains to be 

 learned in regard to turning the observations to practical account. 

 Two of our southern plants, the so-called "Cow-pea," in its mul- 

 tiform varieties, and Arachis, appear to be the best subjects of 

 research in this department. The increasing utility of the for- 

 mer as a direct or indirect fertilizer, and of the latter in its new 

 applications in the production of a food, after the extraction of the 

 oil, indicates the desirability of experiments at the southern sta- 

 tions. G. L. G. 



3. Modifications of the Cell-icall. — There are two recent com- 

 munications relative to changes in the cell-wall which may be 

 conveniently considered together. Van - Wisselingh points out 

 numerous differences between the formation and character of 

 Suberin and Cutin, of which we here recount only the most 

 important. Suberin is always laid down at a later period than 

 Cutin, and appears on the inner side of the cell-wall, in direct 

 contact w T ith protoplasmic matter, whereas Cutin arises on the 

 outside of epidermal cells, and possesses between itself and the 

 protoplasm a layer of well-marked cellulose. Suberin is more 

 easily saponified by potassic hydrate that Cutin is, and the pro- 

 ducts of saponification differ in appearance from those arising 

 from Cutin. 



The other paper deals with the mucilaginous modification of 

 the walls of cells. Margin (Bulletin Sec. Fr., xli) classifies 

 mucilages into simple and complex, dividing the former again 

 into (t) cellulose mucilages; which are rather rare (a good 

 example is afforded by Salep), (2) pectose mucilages, common in 

 Malvacece, Tiliacece, and certain algre; (3) callose mucilages, 

 confined in the higher plants to the sieve tubes. The second 

 group of mucilages, the mixed, or complex, belong to various 

 seeds. Here we find the cellulose and pectose-mucilages com- 

 mingled in different amounts. 



According to Guiraud, the mucilage in Malvacece is found to 

 some extent in all organs, and comes from the breaking down of 

 the walls of certain cells in the secondary parenchyma. It may- 

 be retained in special cells, or it may overflow from them. 



The existence of nitrogen in the so-called mucilage of at least 

 two species of Dioscorea may be regarded as settled by the work 

 of Ishij, of Japan. The mucin here found is essentially like that 

 occurring in animals. G. l. g. 



4. On the accumulation of sugar in the root of the Beet. 

 (ComptesRend., 2 Dec. 1895.) — L. Ma quenne calls attention to the 

 difficulty of explaining the equilibrium which exists between the 

 leaves and the root of beets, considering the chemical composi- 

 tion of the two. It is easy to understand how the carbhydrates 

 elaborated by the chlorophyll-bearing cells reach the root by 



