158 BOTANICAL GAZETTE [FEBRUARY 
more and more come to be regarded as a branch of physiology proper. The 
theory of representative particles must be relegated to the class of formal hypothe- 
ses whose usefulness is largely outlived; and while it may still play a part in specu- 
lations on heredity, the author believes that it will come to be generally recognized 
by those who use it as a mere matter of convenience of terminology, and not as 
an explanation of the phenomena described in its terms.—J. M. C. 
The rdle of glucosides.—WEEVERS continues his researches on the glucosides 
of plants, with investigations of arbutin and salicin, and their allies.t* He reports 
that both are to be considered as reserve foods, the combination of benzol deriva- 
tives with glucose serving to form compounds of low diffusibility, and therefore 
suitable for the accumulation of sugar in the cells. Arbutin in Vaccinium Vitis- 
idaea is localized in the leaves, and is used in the spring when the shoots develop, 
being split by an enzyme into glucose and hydrochinon. The latter remains in 
the leaves and is used again to combine with the glucose formed by photosynthesis, 
none being free in autumn. Pirus communis contains a glucoside which is prob- 
ably identical with arbutin, and behaves in the same way. In Salix purpurea 
and Populus monilijera there appears to be a complex of enzymes, of which one, 
salicase, splits salicin into saligenol and glucose; another, saligenase, destroys 
saligenol and produces catechol; and a third breaks up catechol, forming a black 
amorphous insoluble pigment. This catecholase, however, gets at catechol only 
on decay of the tissues. All summer, salicin is formed daily in the leaves; nightly 
it is hydrolyzed and the glucose is carried away to the cortex. When in autumn 
the salicin content of the cortex approaches that of the leaves, this process stops- 
Populin is another product common to the two genera, but more variable 
in behavior. Populase forms catechol from it also.—C. R. B 
Hindi cotton.—Coox”? has published a statement in reference to Hindi cotton,” 
the interest of which extends beyond the immediate cultural problem. The name 
is applied in Egypt to an undesirable type of cotton that injures the high-grade 
varieties by infesting them with hybrids. The introduction of Egyptian cotton 
into the United States has introduced also the problem of Hindi cotton. There 
has been much speculation as to the nature and origin of this pernicious type, the 
name having suggested an origin from India. Experiments with Egyptian cotton 
in Arizona resulted in the appearance of the so-called “Hindi” variations, eg 
comparison with other types show that Hindi cotton is of American origin. Its 
not identical with any of the upland varieties of the United States, but is to be 
associated with upland types indigenous in Mexico and Central America. Egyp- 
tian and other Sea Island types also have originated in tropical America, and the 
author concludes that “‘it becomes possible to view the Hindi variants as 
tt WEEVERS, TH., Die physiologische Bedeutung einiger Glycoside. (Fortset- 
zung.) Recueil Trav. Bot. Néerl. 7:1-62. 1910. 
12 CooK, O. F., Origin of the Hindi cotton. ‘Circ. 42, Bur. Pl. Ind., U. S. Depart 
Agric. pp. 12. figs. 2. 1909. 
