THE BLADDERWORT 



the bodies of the drowning insects. The ferment resembles 

 the active principle of the gastric and pancreatic juices of the 

 human body, and, as acids are also present, the insect's body 

 becomes changed into nutritious juices which readily diffuse 

 into the plant.^ Dr. Macfarlane found that when the 

 pitchers were stimulated by being given insects, the liquid 

 inside them could digest fibrin to jelly in from three-quarters 

 to one hour'*s time.^ But certain insects have somehow 

 managed to educate their larvae to resist the gastric juices of 

 Nepenthes. 



Near Fort Dauphin, in Madagascar, I found great quanti- 

 ties of Nepentlies madagascariensis. Almost every pitcher was 

 one-third to two-thirds full of corpses, but in some of them 

 large, fat, white maggots, of a very unprepossessing appear- 

 ance, were quite alive and apparently thriving. These must 

 have been the larvae of a blowfly similar to that which has 

 been mentioned by others as inhabiting Sarracenia. At the 

 same place a white spider was very often to be seen. Its 

 web was spun across the mouth of a pitcher, and its body 

 was quite invisible against the bleached remains inside. 



It had suited its colour to the corpses within, in order that 

 it might steal from the Nepenthes the due reward of all its 

 ingenious contrivances ! 



A totally different arrangement is found in an incon- 

 spicuous and ugly little marsh and ditch plant called Utri- 

 cularia or Bladderwort. It is very difficult to see, for unless 

 it happens to be in flower it is entirely submerged in the 

 water. The flowers, which are purple, are conspicuous and 

 easily seen even at a distance. On these submerged leaves 

 there are hundreds of small bladders. They are about the 



^ Green, Vegetable Physiology, p. 203. 



2 Annals Botany, vol. 3, p. 253, and vol. 6, p. 401. 



345 



