( 193 ) 
Botany. “The physiological significance of certain glucosides” 
By Dr. Th. Weevers. (Communicated by Prof. F. A. F. C. Went). 
In the Proceedings of the ordinary meeting of the Mathematical 
and Physical Section of September 27 th 1902 there appeared an 
account of some investigations on glucosides in relation to plant 
metabolism, and of this the present paper is to be considered a 
continuation. 
It was shown at the time that both salicin from Salix purpurea L. 
and the glucosides from the seeds of Aesculus Hippocastanum L. 
are reserve materials; the former substance is used in the opening 
of the buds, the latter in germination. 
At the opening of the buds of Salix purpurea saligenol 1 ) appears, which 
points to a hydrolysis of salicin; the quantity found was, however, 
so small, that the actual aromatic product must be another substance, 
and as such I regarded catechol, which can be demonstrated in all 
parts of the plant. When the salicin diminishes, the catechol increases 
and in various cases the change in the amount was found to be 
roughly proportional to the molecular weights. These quantitative 
experiments induced me to suppose that catechol, after hydrolysis ot 
the salicin and transport to other parts of the glucose thus formed, 
remains localised in the cell and again combines to form salicin 
with glucose, which is brought from elsewhere or has been formed 
on the spot by assimilation. Thus Pfeffer’s. hypothesis wonld be 
confirmed, that the compounds of benzene derivatives with carbo¬ 
hydrates serve to form substances not easily diffusible; in the present 
case catechol would form with the transport substance, glucose, the 
reserve substance salicin. 
In the later investigation the validity of this supposition was tested 
on another giueoside, namely arbutin, which accompanied by small 
quantities of methylarbutin, occurs in numerous Ericaceae. Similarly 
the occurrence of fairly large quantities of hydroquinone, the aromatic 
product of arbutinhydrolysis is recorded for these Ericaceae. Ex¬ 
periments with Vaccinium vitis idaea L. showed, however, that the 
latter statement is not quite correct; generally the amount of free 
hydroquinone is very small, and in autumn it is even zero; it 
increases, however, considerably during the formation of the young 
shoots in spring. 
Arbutin is rapidly hydrolysed by an enzyme, which 1 obtained 
from Vaccinium vitis idaea, so that only those quantitative deter- 
l ) Saligenol — salicylalcohol; catechol = orthodioxybenzene. 
