354 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Enghis man, the contemporary of the mammoth ; the third 

 was the diluvial, which includes the period of the reindeer 

 and a few other mammals, which have retreated toward the 

 north or into the high mountains ; and the fourth the mixed, 

 or Celto-Germanic, in which the implements of the Stone Age 

 are found, together with those of the Bronze andiron. 



As a memorial of its deceased member, the Academy of 

 Sciences of Belgium has added the following to the prize 

 questions of 1874: The polymorphism of the mushrooms is 

 attracting more and more the attention of botanists and 

 physiologists, and seems suited to furnish new elements for 

 the solution of the problem of life in general. First, a suc- 

 cinct and critical summary of the known observations of the 

 polymorphism of the mucedinse is demanded; second, an ex- 

 act determination, even if based upon a single species, of 

 what relates, first, to the proper nature of the plant (its spe- 

 cific energy), and, second, to the exterior (the conditions of 

 its development) ; third, the positive proof or disproval of 

 the fact that the fungi of ferments, such as micrococcus, pal- 

 mella, mycodermi, etc., under any circumstances, can be trans- 

 formed into the higher fungi. Bulletin Acad. Boy ale deBel- 

 gique, February r , 1872, 103. 



UTILITY OF THE WATER-PEST PLANT. 



The American water-plant {Elodea Canadensis), which, un- 

 der the name of Water Pest, has caused so much alarm in 

 Europe by its rapid propagation in canals and streams, it is 

 stated, serves a very important purpose as a purifier of water, 

 especially in destroying the taste and smell of sewerage. It 

 is admirably adapted, too, as a nutriment for young herbivo- 

 rous fish, and as a refuge for young fish of any kind, and can 

 be introduced to great advantage in fish-breeding establish- 

 ments. It also furnishes an excellent manure for soils poor 

 in lime and other inorganic constituents, as it contains an 

 unusual percentage of lime, soda, potash, magnesia, and silica. 

 The separation of these ingredients from the water tends to 

 purify it, and render it much softer and more serviceable in 

 domestic economy than otherwise. Indeed, the plant will not 

 thrive in water that does not contain lime, at least in an ap- 

 preciable amount ; and when planted in a pond, it dies out 

 as soon as the water is brought to a condition of approxi- 

 mate freedom from mineral ingredients. 2 C, April, 1872, 65. 



