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vellow ; and in those the amount of HCN could also be shown to 
have diminished considerably. 
Branches in hot house 26. 12. Ol. Leaves yellow and falling off 
22. 1. 02. ; weight: 20,10 gr-HCN: 0,0089 er.; i. e. 0,04°/,. 
Moreover, the same is the case with certain leaves directly taken 
from the shrubs grown in the Botan. G. 
27. 4. 02.; 15 yellowish leaves are picked; weight: 24,95 er 
HCN: 0,0158 gr. ; i. e. 0,06°/, ; in one leave: 0,0011 er. 
The figures for fresh leaves, mentioned formerly, show that but a 
small part of the HCN normally present had been retained here. 
As the hvdroeyanie acid was also observed to disappear from the 
cut leaves, when they became yellow, it seems very probable that 
this substance — or its Compounds — are not transferred from the 
leaves to the branches, but must have undergone a chemical trans- 
formation. 
The budding however, at least in the first periods that I examined, 
has no influence whatever on the quantity of prussic acid in the 
leaves and twigs. For instance, 30. 4. 02 were gathered, on the 
cherry-laurels of the Bot. G. Amsterdam, 10 leaves, one year old, 
each being inserted below a well grown young shoot; weight: 
11,60 gr.-HCN: 0,0251 er.; 1. e. 0,22°/,; in one leaf: 0;0025 er: 
These figures are of quite the same order as were yielded in December 
by the same shrub. 30. 4. 02 also were cut, below opening buds, 
twigs one year old; I chose intentionally twigs which though they 
bore numerous, and fairiy big shoots, had no more leaves, these being 
cut or having fallen off at an earlier period, before the budding ; 
weight: 8,25 er-HCN: 0,0086 ger, i. e. 0,10 °/. I have found 
however, in twigs one year old, taken from the different shrubs in 
the Bot. G., during winter, a percentage of HCN ranging from 0,06 
till O11 °/,. It is clear that there was no diminution after the opening 
of the buds. 
Neither was this the case after the budding in the dark. Branches 
having been placed in the hot house, under darkened boxes, 29. 4. 02, 
leaves were cut 4. 5. 02, below etiolated shoots. The percentage: 0,14°/,, 
was the same as leaves from the same shrub had yielded before. 
Finally, it could be shown in P. Padus that, though the young 
branches issued from the winter buds are already considerably deve- 
loped, and bear numerous leaves of fair size, the amount of HCN- 
compounds in the internodes below is still the same as before the 
budding. 
This was observed 25. 4. 02, when 130 internodes of P. Padus, 
from the year before, were taken below long shoots, well furnished 
