( 295 3) 
Although hydrogen sulphide is volatile and most of it escapes during 
the boiling, the increase of the number of molecules formed during 
that action (however small this may be) is large enough to account 
for the observed difference. The fact that the deviation has been 
found larger in the case of toluene than with m-xylene as solvent 
is also in agreement with the observed fact that more hydrogen 
sulphide is evolved in the first than in the second case. 
Our research on the action of sulphur on p-xylene was not conducted 
merely with the idea of confirming the researches of ARONSTRIN and 
MEIHUIZEN (we were not quite sure whether the mm-xylene then used 
had been completely free from p-xylene) but also to throw more 
light on the mechanism of the process and particularly on the ques- 
tion of the primary formation of stilbene and the secondary forma- 
tion of dibenzyl. 
Chemical Laboratory of the Polytechnical School. 
Derrr, September 1902. 
Physiology of Plants. — “J/nvestigations of Glucosides in connection 
with the Internal Mutation of plants,’ by mr. Tu. Weevers. 
(Communicated by Prof. C. A. LoBry pr Bruyn). 
(Communicated in the Meeting of 27 September 1902.) 
The purpose I had in view in this investigation was to trace for 
some plants, whether the amount of glucosides remains unchanged 
during the development or not; and to investigate in the latter case 
by what conditions these changes are determined. 
At the same time the manner in which those changes took place 
formed another subject for study: whether glucosides were trans- 
ported as such, or whether a decomposition could be stated, and in 
the latter case what were the components in which this took place. 
Salix species and Aesculus hippocastanum lL. were especially used 
for the investigations; Gaultheria procumbens L. and Fagus sylvatica 
were also submitted to a prefatory study. 
The glucosides to be mentioned here are salicine for the Salix 
species, gaultherine for Gaultheria and Fagus, aesculine and more- 
over some glucosides not yet chemically determined for Aesculus 
hippocastanum. 
As for salicine the quantitative valuations were made as follows. 
The salicine was entirely extracted by boiling water from the parts 
to he examined: and the extract treated with basie lead acetate. The 
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Proceedings Royal Acad. Amsterdam. Vol, V. 
