Nov. 10,1913 
Alkaloidal Content of Belladonna Plants 
139 
RELATION OR THE ALKALOIDAL CONTENT OF THE LEAVES TO THE STAGE 
OF GROWTH OF THE PLANT 
Opinions have been expressed from time to time as to the proper 
stage in the growth of the belladonna plant at which the leaves should 
be picked in order to insure the greatest percentage of alkaloids. Owing 
to the standard required by the Pharmacopoeia, this is a question of no 
small economic importance. Gerrard 1 has found that the plant is 
not rich in alkaloids before flowering, but that the full development 
is reached at the period of flowering and is maintained in both the roots 
and leaves into the fruiting season. 
The large number of assays of the leaves of individual plants here 
involved presents exceptional opportunity for the study of the above 
question. The proper season for the picking of belladonna leaves does 
not, however, depend entirely on the percentage of active constituents 
present. This will become very evident when the data at hand are 
thoroughly interpreted. Table V shows in condensed form the number 
of plants in which there was an increase or decrease in the percentage 
of alkaloids in the leaves at the various pickings. 
Table V .—Number of belladonna plants which showed an increase or decrease in per¬ 
centage of alkaloids in the leaves at the second , third, fourth , and fifth pickings as 
compared with the preceding picking at Arlington Experimental Farm in ign and IQI2 . 
Stage of growth. 
Season of 1911. 
Season of 1912. 
Total 
number 
of 
plants. 
Number of plants 
which showed— 
Total 
number 
of 
plants. 
Number of plants 
which showed— 
Increase. 
Decrease. 
Increase. 
Decrease. 
Second picking. 
7 ° 
3 * 
32 
59 
16 
43 
Third picking. 
60 
25 
35 
53 
34 
29 
Fourth picking. 
54 
40 
14 
32 
20 
12 
Fifth picking. 
56 
8 
4 * 
23 
4 
*9 
Table V shows that in 1911 the leaves of most of the plants were 
richer in alkaloids at the second picking than at the first, which is in 
accord with the observations of Gerrard, already noted. In 1912, 
however, the opposite is true. It will be seen further that in the fourth 
picking of both years the greatest number of plants showed an increase 
in the alkaloidal content of their leaves. Referring to Table II, it is 
seen that in the fourth picking in 1911 the average quantity of alkaloids 
for the leaves of all the Arlington plants was 0.633 per cent, or more 
than one-tenth of 1 per cent than at the flowering stage. In 1912, at 
1 Gerrard, A. W. On the alkaloidal value of belladonna plants at different periods of growth. Year¬ 
book of Pharmacy, 1881-1882, p. 400-404, 1882. 
