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12,12. 01: 2b Lea 7030225 yar) 0. C0226. eT: HCN 
43: 4912.01. 2b lea O05 1S wrs a Os0501 ten AEN: 
10,1: 902) 25 AS va 0;0288 er. 1D: 0 0242 ror. HON, 
Le 
In the same manner. it could be ascertained that it was quite 
sufficient, after killing at 60°, to macerate during one day only, to 
obtain a complete splitting of the glucoside; also that the heating in 
200—300 em.” at 60°, at two different times or even once, had 
left no living portions in the plant-organs. 
The species studied were Prunus Laurocerasus L. and Prunus 
Padus L. It was chiefly my intention to follow the changes undergone 
by the prussic acid-compounds during the opening of the leaf-buds. 
As of both above named species the second is the earliest, and also 
yielded shoots a long time before the cherry-laurel, when cut bran- 
ches were placed in the hot house, it was with P. Padus that the 
most complete experiments were made, those with P. Laurocerasus 
rather serving to control the former. 
In the very first place, I asked myself the question whether the 
amount of HCN in resting buds — whatever might be the form of 
combination — did exhibit changes, when the buds began to grow. 
To know this, the estimation of the percentage in buds and young 
shoots issued therefrom is insufficient; one must compare the absolute 
quantity of prussic acid contained in a given number of buds with 
the amount in a same number of shoots. As the dimensions of both 
the buds and the shoots vary considerably, a satisfactory medium- 
value could only be obtained by the analysis of a great number of 
these objects, a precaution already made necessary on account of the 
buds being small. 
The amount of HCN contained in resting buds of P. Padus will 
appear with sufficient exactness by the following three estimations: 
10. 2. 02. 195 buds (Bot. G. Amsterdam); weight: 4,80 er.-HCN: 
0,0067 er, i.e. 0,14 °/,; in 100 buds: 0,0034 gr. 
11. 2. 02. 280 buds (B. G. Amsterdam); weight: 6,35 gr.-HCN: 
0,0094 er, i.e. 0,15 °/,; in 100 buds: 0,0034 er. 
20. 3. 02. 100 buds (B. G. Amsterdam; the buds are about to 
open, many show a green top); weight: 2,75 gr.-HCN: 0,0040 er., 
ie: 0,15 °/): an 100 buds: 00040 ser. 
In the first two analyses, the buds, as always was the case with 
the parts examined, in order to avoid losses of hydroeyanie acid, 
were immersed in water without being cut into fragments, and killed 
by heat. However, as it might be feared that the bud-scales should 
hinder the diffusion of glucoside and enzyme, the buds were, in the 
