1918] CURRENT LITERATURE 199 
ship with the Amentiferae. In fact, this relationship is one argument for the 
primitive character of the Amentiferae.—J. M. C. 
Translocation of sugar.—MANGHAM® has attempted to show that adsorp- 
tion in the complex colloidal system of the protoplasm may play an important 
role in the translocation of sugar in the plant. The discussion is purely hypo- 
thetical, and it is rather hard to see how the main hypothesis is to be put on an 
experimental basis. A quotation from his summary will show the line of his 
reasoning. ; 
rption compounds of ceaeNe — = —* are arab Pot is ae 
gested that in vegetable protoplasm 
sugars from solution. For any given concentration of sugar present in the Hiquid 
phase of the protoplasm, and the cell sap continuous with it, there would be a definite 
concentration of sugar present at ~ adsorbing surface. fay —— = concentra- 
tion in either region would lead to which 
would be propagated as a wave Pons the system composed of the adsorbing particles 
and the solution immediately in contact with them. The rate of propagation of this 
wave would depend mey much ong the degree of dike Cees - et a under 
SSeS and Connecting 
reads are assumed to provide a continuous protoplasmic siaay, though they 
— restrictions varying with their frequency and tenuity. 
2 
Diffusion is generally recognized as being too slow to account for the con- 
siderable movement of sugars and other materials in plants. There must be 
mass movement to supplement molecular movements. MANGHAM’s hypoth- 
esis does not help us out in this respect because it must assume that “read- 
justment of concentration equilibrium” is brought about by diffusion so far 
as movement of the sugar molecule is concerned. The line between adsorption 
compounds and compounds due to chemical reactions is by no means a sharp 
one. In fact, it is one of the great battle lines in physical chemistry. One 
seriously doubts whether anything is gained by his assumption of adsorption — 
compounds. There is much more evidence to support his view that sugar 
travels from cell to cell mainly by protoplasmic connections rather than by 
passing through the ectoplast, which is almost impermeable to sugar.—W™. 
CROCKER. 
Physiological diseases.—BONCQUET”® claims to have solved the mystery 
of certain plant diseases of the so-called physiological type, such as curly top 
** MancHAM, SypNEy, On the mechanism of translocation in plant tissues. A 
hypothesis, with special reference to sugar conduction in sieve tubes. Ann. Botany 
31:203-311. 1917. : 
*® Boncguet, P. A., Presence of nitrites and ammonia in diseased plants. Jour. 
Boncquet, P. A., and Rowcooky: Mary, Presence of nitrites and ammonia in 
diseased plants. II. Oxidases and diastases; their relation to the disturbance. 
Jour. Amer. Chem. Soc. 39: 2088-2093. 1917. 
