CONSTITUENTS OF PLANTS. 



41 



manuring them with such substances as shav- 1 

 ings of horn, Sec. ; but after some years the ' 

 formation of the wood and leaves decreased j 

 to the great loss of the possessor, to such a | 

 degree that he has long had cause to regret 

 his departure from the usual methods. By 

 the manure employed by him, the vines had 

 been too much hastened in their growth ; in 

 two or three years they had exhausted the 

 potash in the formation of their fruit, leaves, 

 and wood, so that none remained for the fu- 

 ture crops, his manure not having contained 

 any potash. 



There are vineyards on the Rhine the 

 plants of which are a hundred years old, 

 and all of these have been cultivated by 

 manuring them with a cow-dung, a manure 

 containing a large proportion of potash, 

 although very little nitrogen. All the potash, 

 in fact, which is contained in the food con- 

 sumed by a cow is again immediately dis- 

 charged in its excrements. 



The experience of a proprietor of land in 

 the vicinity of Gottingen offers a most re- 

 markable example of the incapability of a 

 soil to produce wheat or grasses in general, 

 when it fails in any one of the materials ne- 

 cessary to their growth. In order to obtain 

 potash, he planted his whole land with 

 wormwood, the ashes of which are well 

 known to contain a large proportion of the 

 carbonate of that alkali. The consequence 

 was, that he rendered his land quite incapa- 

 ble of bearing grain for many years, in con- 

 sequence of having entirely deprived the 

 soil of its potash. 



The leaves and small branches of trees 

 contain the most potash; and the quantity 

 of them which is annually taken from a 

 wood for the purpose of being employed as 

 litter,* contain more of that alkali than all 

 the old wood which is cut down. The 

 bark and foliage of oaks, for example, con- 

 tain from 6 to 9 per cent, of this alkali ; the 

 needles of firs and pines, 8 per cent. 



With every 2650 Ibs. of firwood which 

 are yearly removed from an acre of forest, 

 only from (H14 to 0'53 Ibs. of alkalies are 

 abstracted from the soil, calculating the 

 ashes at O83 per cent. The moss, however, 

 which covers the ground, and of which the 

 ashes are known to contain so much alkali, 

 continues uninterrupted in its growth, and 

 retains that potash on the surface, which 

 would otherwise so easily penetrate with 

 the rain through the sandy soil. By its de- 

 cay, an abundant provision of alkalies is 

 supplied to the roots of the trees, and a fresh 

 supply is rendered unnecessary. 



* [This refers to a custom some time since 

 very prevalent in Germany although now discon- 

 tinued. The leaves and small twigs of trees 

 were gleaned from the forests by poor people, for 

 the purpose of being used as litter for their cattle. 

 The trees, however, were found to suffer so much 

 in consequence, that their removal is strictly pro- 

 hibited. The cause of the 'njury was that stated 

 ; n tbe text. ED.] 



6 



The supposition of alkalies, metallic ox- 

 ides, or inorganic matter in general, being 

 produced by plants, is entirely refuted by 

 these well-authenticated facts. 



It is thought very remarkable, that those 

 plants of the grass tribe, the seeds of which 

 furnish food for man, follow him like the 

 domestic animals. But saline plants seek 

 the sea-shore or saline springs, and the 

 Chenopodium the dunghill from similar 

 causes. Saline plants require common salt, 

 and the plants which grow only on dung- 

 hills need ammonia and nitrates, and taey 

 are attracted whither these can be found, 

 just as the dung-fly is to animal excrements. 

 So likewise none of our corn-plants can 

 bear perfect seeds, that is, seeds yielding 

 flour, without a large supply of phosphate 

 of magnesia and ammonia, substances which 

 they require for their maturity. And hence, 

 these plants grow only in a soil where these 

 three constituents are found combined, and 

 no soil is richer in them than those where 

 men and animals dwell together; where the 

 urine and excrements of these are found 

 corn-plants appear, because their seeds can- 

 not attain maturity unless supplied with the 

 constituents of those matters. 



When we find sea-plants near our salt- 

 works, several hundred miles distant from 

 the sea, we know that their seeds have been 

 carried there in a very natural manner, 

 namely, by wind or birds, which have 

 spread them over the whole surface of the 

 earth, although they grow only in those 

 places in which they find the conditions 

 essential to their life. 



Numerous small fish, of not more than 

 two inches in length (Gasterosteus aculeatus,} 

 are found in the salt-pans of the graduating 

 house at Nidda (a village in Hesse Darm- 

 stadt.) No living animal is found in the 

 salt-pans of Neuheim, situated about 18 

 miles from Nidda; but the water there con- 

 tains so much carboriic acid and lime, tbat 

 the walls of the graduating house are covered 

 with stalactites. Hence the eggs conveyed 

 to this place by birds do not find the condi- 

 tions necessary for their developement, 

 which they found in the former place.* 



* The itch-insect (Acarus Scabiei) is considered 

 by Burdach as the production of a morbid condi- 

 tion, so likewise lice in children ; the original 

 generation of the fresh-water muscle (mytilus) in 

 fish-ponds, of sea-plants in the vicinity of salt 

 works, of nettles and grasses, of fish in pools of 

 rain, of trout in mountain streams, &c., is ac- 

 cording to the same natural philosopher not im- 

 possible. A soil consisting of crumbled rocks, 

 decayed vegetables, rain and salt water, &c., is 

 here supposed to possess the power of generating 

 shell-fish, trout, and saltwort (salicornia.) All 

 inquiry is arrested by such opinions, when propa- 

 gated by a teacher who enjoys a merited reputa- 

 tion, obtained by knowledge and hard labour. 

 These subjects, however, have hitherto met 

 with the most superficial observation, although 

 they well merit strict investigation. The dark, 

 the secret, the mysterious, the enigmatic, is, in 

 fact, too seducing for the youthful and philosophic 



D 2 



