o 



76 



Marvels of the Universe 



termed " bladders," and are borne amongst the 

 leaves, of which they are modified portions. 



In the accompanying photo-micrograph they 

 will be seen to be somewhat pear-shaped structures 

 supported on short footstalks. The entrance is 

 at the narrow end, and is closed with an elastic 

 valve which opens inwards. \Mien the prey is 

 scarce the valves act very promptly, giving way the 

 moment they are touched, and precipitating the 

 inquiring water-flea, or other animal, into the 

 interior, and then immediately closing again. It 

 is quite impossible for the captive to escape, as 

 the valve cannot be opened from the inside. Around 

 the entrance of the bladder are several branched 

 bristles, which probably serve to conduct the prey 

 to the vicinity of the valve. 



The bladder often contains several water-fleas 

 or similar organisms, which will sometimes remain 

 alive for two or three days, but eventually they 

 perish and begin to decay. Inside the bladders, 

 too, are numerous living animalculje which seem 

 to thrive on the decaying prey. Whether these 



Phut^. (,»] {J. J. Ward. F.E.S. 



THE BL.ADDERWORT-S TRAPS. 



A few of the bladders that constitute the traps by 

 means of which the plant catches its food, on a scale of 

 magnification which shows them twenlj times larger than 

 life size. 



Photoliy-] {J. J. Word. F.E.S. 



THE BLADDERWORT. 



A portion of the plant, natural size, showing the 

 position of the bladders in which minute aquatic animals 

 are entrapped and done to death. 



are to be looked upon as parasites on the plant's 

 preserves, or whether they in turn serve as further 

 nourishment for the plant, is a difficult point to 

 decide. On the inside walls of the bladders are 

 innumerable minute glands (which are visible as 

 little points in the photo-micrograph), and it is 

 these organs which supply to the plant its nitro- 

 genous food. They absorb the material after it has 

 reached the condition of a liquid manure, and do 

 not, so far as Charles Darwin's experiments showed, 

 digest their prey in the manner of the Sundew and 

 Butterwort previousl}' considered. 



\^'hat is perhaps the most curious point regard- 

 ing the Bladderwort is what induces the tiny prey 

 to go so readily to its slaughter. It may be the 

 naturally inquisitive characteristics of these or- 

 ganisms for penetrating crevices that lead them 

 into trouble ; but the valve of the bladder is 

 transparent, and possibly that may be the attrac- 

 tion. It may create a bright spot which acts as a 

 lure, and so draws the victims to the entrance. 

 Then, shordd they stumble against the valve, they 

 are immediately entrapped. 



