202 The Romance of Wild Flowers 
he was further drawn by its well-known relation- 
ship to the Butterworts. Mr. Holland’s observation 
and supposition were fully supported, not only by 
Darwin, but also by Cohn, who in 1875 published a 
memoir on the subject. Speaking of the first 
observations made by him and his son, Darwin says: 
“My son examined seventcen bladders, including 
prey of some kind, and eight of these canes 
entomostracan crustaceans, three larve of insects, 
one being still alive, and six remnants of animals 
so much decayed that their true nature could not 
be distinguished. I picked out five bladders which 
seemed very full, and found in them four, five, eight, 
and ten crustaceans, and in the fifth a single much 
elongated larva. In five other bladders, selected 
from containing remains, but not appearing very 
full, there were one, two, four, two and five crustaceans. 
A plant of Utricularia vulgaris, which had been 
kept in almost pure water, was placed by Cohn one 
evening into water swarming with crustaceans, and 
by next morning most of the bladders contained 
these animals entrapped and swimming round and 
round their prisons. They remained alive for 
several days; but at last perished, asphyxiated, as 
I suppose, by the oxygen in the water having been 
all consumed.” 
