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I 



riability itself of différent parts differs considerably, and 

 secondly whether bad nutrition causes either an increase 

 or a decrease of the variability for ail characters, or an 

 increase for some and a decrease for others. 



With the object of answering thèse questions, I made 

 some culture experiments in the botanical garden at 

 Groningen in the summer of 1903. The description and 

 results of thèse experiments will be found in what follows. 



For the cultures four beds of 2 mètres breadth and 6 

 mètres length were prepared in April. Two of them were 

 manured with hornmeal, about half a kilogram per square 

 mètre. The other two beds were dug out to a depth of 

 about half a mètre and filled with a very meagre loamy 

 sandsoil, originating from Harendermolen, a sandy région 

 in the neighbourhood of Groningen. In the middle of April 

 on one of the manured beds and on one of sandy soil 

 equal quantifies of seed were sown of Iberis amara Linn., 

 obtained from H a a g e and S c h m i d t at Erfurt, Ranimculus 

 arcensis Linn., oblained from varions botanical gardons 

 and mixed, and of Malva vulgaris Fr. [Malva rolundifolia 

 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 ail out and to sow afresh. This 

 time Anelhum graveolens Linn., from the trade, Scandix 

 Pecten-Veneris TÂnn. 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 germinatlng dishes, each species partly 

 in meagre and partly in fertile earth taken from the beds 

 in the garden. In the course of the foUowing days part 

 of the germplants were placed into small pots with meagre 

 as well as with manured earth, spécial care being taken 



