1846.] Spontaneous Changes of Organized Matter. 211 



as these combine with the albumen of the juices and render them 

 insohible, and the wood will be protected from decomposition. 

 When the roots, leaves, &c., are left upon and in the soil, they 

 are converted into a substance which partly by their power of 

 absorbing oxygen are converted into a substance which contri- 

 butes powerfully to the growth of the succeeding race of plants, 

 and thereby constitute the essential element of every fertile soil. 

 Turf or peat, as it is usually called in this country, contains hu- 

 mous and humic acids; the latter is remarkable for its strong at- 

 traction for ammonia, so much so, that it is with difficulty that it 

 is separated from it by any reagent whatever. 



It is found in the black turf which is submerged beneath water, 

 and from its strong attraction for ammonia is an important ele- 

 ment in the formation of composts. Two other bodies differing 

 from the preceding are also found in the organic matter of soils, 

 viz., crcnic and apocrenic acids. Their name simply implies that 

 they were obtained, or derived from, 2i fountain or spring. These 

 are azotized acids, and are also the products of animal as well as 

 vegetable matter. They are known to exist in the softer rocks 

 as the polishing slate of Germany, and from the fact that it con- 

 tains animal matter, it has been used for food in times of scarcity. 

 We have obtained the same acids from a much older system of 

 rocks in New York, as may be seen from the articles in this and 

 the preceding number. 



Crenic acid is described in books as a pale yellow gummy 

 mass, of an astringent taste, and slightly bitter, very soluble both 

 in alcohol and water. Exposure to the air converts it into apo- 

 crenic acid, which is brown and also astringent, but is much less 

 soluble in alcohol or water than crenic acid. 



The composition of crenic acid is represented by the formula, 

 N. C. 14, H. 16, 0. 12, and apocrenic acid by N. 6, C. 28, H. 

 14, 0. 6, from which it will appear that the latter contains more 

 nitrogen than the former. Now, manures have been proved to be 

 valuable in the direct ratio of the quantity of nitrogen they con- 

 tain; hence these substances possess fi-om their composition an 

 intrinsic value over and above those which are destitute of i^ 



