16 DROSERA ROTUNDIFOLIA. (Cuap. I. 
least flourishing half of each culture was selected to be “ fed,” 
while the rest of the plants were destined to be “starved.” 
The plants were prevented from catching insects for them- 
selves by means of a covering of fine gauze, so that the only 
animal food which they obtained was supplied in very 
minute pieces of roast meat given to the “fed” plants but 
withheld from the “starved” ones. After only 10 days the 
difference between the fed and starved plants was clearly 
visible: the fed plants were of brighter green and the 
tentacles of a more lively red. At the end of August the 
plants were compared by number, weight, and measurement, 
with the following striking results :— 
Starved. Fed. 
Weight (without flower-stems) . . - 100 121°5 
Number of flower-stems . . . «. + 100 164°9 
Weight ofstems . . . « 2 6 100 231°9 
Number of capsules . . . . + 100 194°4 
Total calculated weight of seed . . . 100 5379°7 
Total calculated number of seeds. . 100 241°5 
These results show clearly enough that insectivorous 
plants derive great advantage from animal food. It is of 
interest to note that the most striking difference between the 
two sets of plants is seen in what relates to reproduction— 
i.e. in the flower-stems, the capsules, and the seeds. 
After cutting off the flower-stems, three sets of plants were 
allowed to rest throughout the winter, in order to test (by a 
comparison of spring-growth) the amounts of reserve material 
accumulated during the summer. Both starved and fed 
plants were kept without food until April 3rd, when it was 
found that the average weights per plant were 100 for the 
starved, 213-0 for the fed. This proves that the fed plants 
had laid by a far greater store of reserve material in spite of 
having produced nearly four times as much seed. 
In Kellermann and Von Raumer’s experiments (loc. cit.) 
aphides were used as food instead of meat—a method which 
adds greatly to the value of their results. Their conclusions 
are similar to my own, and they show that not only is the 
seed production of the fed plants greater, but they also form 
much heavier winter-buds than the starved plants. 
Dr. M. Biisgen has more recently published an interesting 
paper* on the same subject. His experiments have the 
* “Die Bedeutung des Insectfanges fiir Drosera rotundifolia (L.),” ‘ Bot. 
Zeitung,’ 1883. 
