722 
Insect- Capture . 
[December, 
14 fed plants yielded 17 heads of blossom, whilst 16 unfed 
plants produced 7. The 14 fed plants had 90 seed-capsules, 
the 16 unfed plants only 20. An enumeration of the leaves 
could in this stage be no longer of importance, but a super- 
ficial census showed on 14 fed plants 194, and on 16 unfed 
plants 222. 
Of the thirty-six plants with which the experiment was 
begun there died altogether six, four fed and two unfed. If 
we are unwilling to ascribe this proportion to accident, it 
still does not affeCt the result. If, in nature, the number of 
the plants which die yearly is increased by the consumption 
of inseCt prey, this loss is covered by the more luxuriant 
fructification of the survivors. 
The last doubts as to the benefits of feeding in the case 
of Drosera rotundifolia were removed by a determination of 
the total weight of the plants when dried. The figures 
were : — For the fed plants 0*352 grm., for the unfed ones 
o*iio. The solid matter absorbed by the latter in the 
course of their development amounted therefore only to 
33*8 per cent of that assimilated in the same length of time 
with the aid of animal food. 
Herr Busgen has carried out several other series of com- 
parative experiments in which the conditions of nutrition 
were less favourable. Thus to one series of plants there 
was given, instead of the culture-solution, spring water and 
distilled water : in the second series there was used a liquid 
containing potassium chloride in place of potassium nitrate ; 
the results were, however, similar to those already given. 
In a communication to the “ Botanische Zeitung ” Herr 
Busgen summarises the results of his investigations as fol- 
lows : — We must regard it as demonstrated that the organism 
of Drosera rotundifolia is supplied through its leaves with 
animal matter which is of great importance for the develop- 
ment of the plant, and especially for its fructification. The 
necessity of this method of nutrition for the preservation of 
the species could only be proved by the cultivation of several 
successive generations. Its demonstration would, however, 
present little especial interest. The demonstrated advantage 
of the fed plants as compared with those not fed is sufficiently 
strikingto make the arrangements for this purpose intelligible. 
There can be little doubt that similar results would be 
obtained on careful experimentation with other insectivorous 
plants. 
