74 



THE AQUARIUM, OCTOBEIi, 1893. 



without doubt. He describes this fluid 

 as having a styptic taste, being poison- 

 ous, or at least liaving a narcotic influ- 

 ence on insects. Insects that have fall 

 en into this fluid lose the power of 

 motion in half a minute, but will re- 

 cover if soon removed from its influence. 

 The process of digestion, he claims, is 

 nothing more than a form of decom- 

 position. The juices of the many 

 varieties of pitcher jilants found in 

 greenhouses have been examined by Dr. 

 Hooker, and he found that their prop- 

 erties of digesting boiled albumen, 

 raw meat, cartilage, etc., was really 

 wonderful. The pieces were fully dis- 

 solved in from two to three days and 

 that more readily in the pitcher shaped 

 leaf, than when the fluid was put in a 

 glass vessel. Dr. Hooker, therefore, 

 comes to the conclusion that the glands 

 on the interior of the leaf secretes a 

 fluid containing a substance similar to 

 pepsin of the animal stomach. This 

 characteristic trait of preying, seems to 

 be limited to the small family of sun- 

 dew plants, to which class Venus' fly- 

 trap belongs. 



The head gardener, B. Stein, of Ber- 

 lin, noticed a plant in the South of Eu- 

 rope with the same characteristics. This 

 plant was introduced from India about 

 the same time as the Drosera. The name 

 it received is Aldrovanda vesiculosa. 

 (See illustration in last number.) He 

 found this plant growing in ditches in 

 great masses, not far distant from Ry- 

 brink, and convinced himself that every 

 closed leaf contained an insect. This 

 2)lant showed that in water of a tempera- 

 ture of (30° C.) 86° Fahrenheit, to be the 

 most sensitive of the whole family, be- 

 cause he only had to touch the leaf with 

 a wire to make it close itself along the 

 central rib most energetically. A pin 

 thrown on tlie surface of the leaf was 



caught and held from 18 to 20 hours 

 before it was again let fall. This high 

 degree of sensibility was only noticed in 

 a very warm atmosphere. At a low 

 temperature several of the leaves re- 

 mained closed, and this also occurred 

 when the plant was removed from the 

 water. Since this Prof. Cohn, of Bres- 

 lau, has discovered in a plant found in 

 the ditches of meadows in Germany sim- 

 ilar phenomena. This plant, the Helm 

 or Bladderwort ( rfricularia vuhjaris), 

 (which, by the way, is very abundant 

 in several species in many parts of the 

 United States), possessed small bladders 

 or dilatations on the thread-like leaves 

 under the water. The bladders have 

 valve-like openings, which can only be 

 opened from the outside, giving easy en- 

 trance to small animals, but j)revent- 

 ing all escape. These bladders, when 

 opened, are filled with the skeletons of 

 water fleas, worms, smallest >jf crabs and 

 waterbugs, the softer parts of which hav- 

 ing been absorbed by the plant. We can 

 obtain a very excellent description of 

 these plants of prey in a book, f i-om the 

 masterly pen of Emii Schmidt. In 

 conclusion, we would draw the atten- 

 tion of the readers to the pleasure that 

 can be derived from the observation of 

 the chase and waylaying of these plants. 

 They may be found in swamps in any 

 warm climate. Taking these plants 

 from the swamp with considerable of 

 the earth or moss adhering to the roots, 

 and planting them in a pot containing 

 the same sort of soil, they may very 

 readily be kept for some time. We have 

 amused ourselves for weeks with these 

 plants, which always showed the dew- 

 like exudation and retain their sensi- 

 bility. We can find no finer ornament 

 for our Terraria than this sun-dew. 

 What pleasure it is, after feeding the 

 Gold-fish in the morning, to also present 



