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rent parts differs considerably, and secondly whether bad nutrition 
causes either an increase or a decrease of the variability for all 
characters, or an inerease for some and a decrease for others. 
With the object of answering these questions, I made some culture 
experiments in the botanical garden at Groningen in the summer of 
1903. The description and results of these experiments will be found 
in what follows. 
For the cultures four beds of 2 metres breadth and 6 metres length 
were prepared in April. Two of them were manured with hornmeal, 
about half a kilogram per square metre. The other two beds were 
dug out to a depth of about half a metre and filled with a very 
meagre loamy sandsoil, originating from Harendermolen, a sandy 
region in the neighbourhood of Groningen. In the middle of April 
on one of the manured beds and on one of sandy soil equal quan- 
tities of seed were sown of J/beris amara Linn., obtained from 
Haace and Scumpr at Erfurt, Ranunculus arvensis Linn., obtained 
from various botanical gardens and mixed, and of Malva vulgaris Fr. 
(Malva rotundifolia Linn.), obtained from the botanical garden at 
Leiden. The seeds of three other species, which were sown at the same 
time on the remaining two beds, did not germinate in sufficient 
numbers, so that about the middle of June we resolved to weed 
them all out and to sow afresh. This time Anethum graveolens 
Linn., from the trade, Scandix Pecten- Veneris Linn. and .Cardamine 
hirsuta Linn., both obtained from various botanical gardens were 
chosen, three species of which it might be expected that, although 
sown so late in the summer, they might still fully develop. This 
seed was sown in germinating dishes, each species partly in meagre 
and partly in fertile earth taken from the beds in the garden. In the 
course of the following days part of the germplants were placed 
into small pots with meagre as well as with manured earth, special: 
care being taken that no selection from the germplants should be 
made. At the middle of July the young plants were placed in the 
beds at such distances from each other that each could freely develop. 
Already at the beginning a considerable difference between the two 
cultures could be observed in all three species sown in the garden. 
The seed in the bed that had been manured with hornmeal came 
up sooner and the plantlets developed much more vigorously. With 
Malva vulgaris the difference between the plants’ of the two beds was 
at first very great. Those on the fertile soil showed already abundant 
leaves and flowers when the plants on the sandy soil had only 
formed few and small leaves. This difference remained till the begin- 
ning of July, when suddenly also the plants on the meagre soil 
