146 
Journal of Agricultural Research 
Vol. I, No. 2 
Tabus VIII .—Alkaloidal content of the leaves of belladonna plants , rich and poor in 
alkaloids , at various stages of growth , in igil and 1912. 
Plants with leaves of low alkaloidal content (per cent). 
Stage of growth 
(picking). 
No. 3. 
No. 23. 
3 
p 
No. 46. 
1911. 
1912. 
1911. 
19x2. 
1911. 
1912. 
1911. 
1912. 
First. 
0.384 
*375 
.277 
•549 
•451 
0. 496 
.366 
■341 
0-335 
o- 337 
.285 
.308 
.588 
*431 
0.418 
■334 
.480 
•483 
*314 
Second. 
0*393 
.448 
.448 
0.348 
•354 
.487 
*425 
0. 292 
• 520 
Third. 
• 526 
*532 
. 200 
Fourth. 
Fifth. 
Average. 
.407 
.429 
■403 
.401 
.414 
.406 
•390 
.406 
Plants with leaves of high alkaloidal content (per cent). 
Stage of growth 
(picking). 
No. 21. 
! No. 29. 
No. iw. 
No. 6w. 
No. 7W. 
1911. 
1912. 
1911. 
1912. 
1911. 
19x2. 
1911. 
1912. 
1911. 
1912. 
First. 
Second. 
Third. 
Fourth. 
0. 535 
•633 
. 669 
.684 
0. 732 
.719 
.781 
0.655 
.914 
.908 
• 547 
0.737 
.647 
• 729 
0.638 
•835 
*587 
.738 
. 612 
0.737 
.642 
• 777 
0. 596 
.879 
•925 
• 7 H 
. 722 
a 847 
* 747 
.882 
. 804 
.558 
0.558 
.831 
.832 
. 727 
•571 
0. 782 
.666 
.646 
.694 
•573 
Fifth. 
Average. 
. 630 
* 744 
• 756 
. 704 
.682 
• 7 i 9 
. 766 
. 768 
• 704 
.672 
SUMMARY 
From the point of view of the percentage of alkaloids present in the 
leaves and the quantity of material available, the leaves can be picked 
to best advantage from the time of flowering until the early berries begin 
to ripen. Although the leaves are richer in alkaloids later in the season, 
they are then too small and sparse for harvesting. 
Thus far nothing has been found to indicate that any correlation 
exists between the physical appearance of the plant and the alkaloidal 
content of its leaves. Luxuriant growth is by no means a criterion of 
the medicinal value of the plant. 
The variation of the percentage of alkaloids in the leaves of the dif¬ 
ferent plants is exceedingly large. This makes it a difficult matter to 
determine to what extent soil and climate influence the development of 
alkaloids. Where such wide variations exist among individual plants, 
the testing of a general sample from all plants collectively is not always 
a safe means of judgment. 
A considerable number of plants with leaves rich in alkaloids in one 
season are found to have equally rich leaves in the following season. 
Furthermore, they frequently manifest the same characteristics at the 
various stages of growth during the season in comparison with other 
plants. The same facts are true with regard to plants which bear leaves 
with a low percentage of alkaloids. 
