48 REMARKABLE PROPERTIES OF PLANTS. 



form of carbonates. The action of all alkaline bases is alike, and all 

 plants must contain them, though it may be in different forms : at 

 least similar quantities of inorganic matter are always found. Corus 

 or vines can thrive only on soils containing potash. Potatoes grown 

 where they are not furnished with earth form a very poisonous alkali 

 in their sprouts. The ashes of the potato is, as compared with oak wood 

 1,500 to 250, and with pine 83, and rye 440. 



JBy sprinkling plants of certain kinds, or the soil in which they 

 grow, with the juices of others, they manifest the properties of those 

 plants from which the juices are taken. The soil of the hyacinth 

 sprinkled with the juice of the American night shade will exhibit the 

 white blossoms in an hour or two of a red color ; but the jnice under- 

 goes no chemical change. So with others whose roots are steeped in 

 solutions of some of the salts. Plants have the property, however, 

 of returning to the soil all things unnecessary to their growth, or which 

 are hurtful to their existence. The nature of soils suitable for plants 

 must be selected with reference to the proportion of these salts found 

 in their ashes. Thus on sandy and calcarious soils containing little 

 potash, grass will not thrive. The leaves and small branches con 

 tain the most potash. 



Some plants are remarkable, particularly those of the grass tribe, the 

 seeds of which supply man with food, in their habit of following him 

 like domestic animals. Some plants require common salt, others require 

 ammonia and are attracted to dunghills. Corn seeds require a large 

 portion of phosphate of magnesia. Hence such plants grow only 

 where these elements are found ; and, as no soil abounds with them 

 so much as that where men and animals dwell, there they are attracted. 

 Saline plants, for like reasons, seek the sea shore, or salt springs. Al- 

 though seeds are carried in various ways to different places, yet the 

 plants will not grow unless they meet with the elements essential to 

 their growth and existence. 



The original generation of plants of peculiar kinds in the vicinity 

 of places affording peculiar substances essential to their life, as sea 

 plants near salt works, &c., is not doubted. So also the generation of 

 fresh water muscles in fish ponds, fish in pools of rain, trout in moun- 

 tain streams, &c., are not deemed improbable circumstances by philos- 

 ophers. Hence a soil consisting of rocks of particular kinds, decayed 

 vegetables, rain and salt water etc., are considered as possessing 

 the power of generating such particular plants as saltwort &c. Plants 

 thrive best by such manures as have completely lost the property of 

 giving color to water. All plants die in soils containing no oxygen. 

 Stagnant water on marshy soils excludes air, but if the water be with- 

 drawn and free access is given to air, a marsh may be changed into a 

 fruitful field. 



In perennial plants a new process of vegetation takes place after the 



