( 300 ) 
DeGeNeER (Journal f. Prakt. Chemie 1879) could not be used on 
account of a flavon-like colouring matter not closer examined, and 
also precipitated by a basic leadacetate. So the method of Prof. BrHRENs 
to determine Indigo was followed. The sublimate of a solution of 
catechol of a known strength in absolute alcohol was compared with 
that of the alcoholic solution of the remainder of the ether evapora- 
ted dry. Now it was examined how much this liquid had to be diluted 
to obtain an equivalent sublimate. The sublimation was performed by 
means of the brass table described by Prof. Wisman. Under certain 
precautions the determination could be accurately made to milligrammes. 
The quantity of catechol of the leaves was in the evening 0.6 pCt. } with one 
M ee Hoo pee ap ay mOrning0. 1, speciitien 
pees with the 
ri nm „vp » bark y y» » evening0.6 , 
; ; same 
II I " i út I VA a morning0.4 " | ; 
specimen. 
So the quantity of the catechol here proved to change in reverse 
order as that of the salicine. In the leaves the salicine diminishes in 
the night, the catechol increases, and in the bark the catechol dimi- 
nishes and the salieine increases. Is there any connection between 
the extent of these changes? 
For that purpose for one and the same object catechol was deter- 
mined as well as salicine. 
200 halves of leaves 8 P.M. 225 mGr. salicine (4.5°/,) + 32 mG. catechol (0.65°/,) 
AN ies jn a) &eAoM. 162, ' (3.39), ) Adan 7 (1.05°/0) 
So 63 mG. salicine less, 20 mG. catechol more. 
The proportion of these values, given the degree of accuracy of 
the determination of catechol, pretty well agrees with the proportion 
of the molecular weights. 
A comparison was also made of the change in salicine with that in 
catechol for leaves budding forth in the dark. 
17 Gr. bark before budding 351 mGr. salicine 36 mGr. catechol 
Ly „ after 7 234 " Dy 1 
budding etiolated shoots DD a y 4 " " 
(a great increase in the bark, in the young shoots only a small 
part of the catechol thus formed to be found) 64 mG. salicine was 
used, 23 mGr. catechol was formed. 
These two values stand in the ratio of 36 to 100, the molecular 
weights in that of 38 to 100. 
So it is very natural to assume here a decomposition of the salicine 
into sugar and catechol with saligenine as intermediate stage (see 
