60 



A heavy yellow precipitate separated on concentration but dis- 

 solved very largely in the fresh portions of the alcohol extract 

 The greater portion of water was finally removed by evaporating 

 four times with 93 per cent alcohol. More water, however, could 

 have been removed by evaporating with absolute alcohol. The 

 trace of clay, remaining after concentration, was filtered off on a 

 dry filter paper and the solution diluted to 500 cc. with 93 per 

 cent alcohol. The total nitrogen was determined on duplicate 25 

 cc. portions of the solution by the Kjeldahl method. The results 

 gave 0.1320 gram nitrogen in the total alcohol extract. 



Tests were made on portions of this alcohol extract for the 

 presence of proteins or protein-like substances. Precipitates were 

 obtained with phosphotungstic acid and lead acetate. A heavy 

 yellow precipitate formed on dilution with water. This yellow 

 precipitate was readily soluble in sodium hydroxide (suggests 

 presence of acids or phenols), and in concentrated hydrochloric 

 acid. The biuret test and Liebermann's reaction both gave nega- 

 tive tests, and Millon's reaction gave an extremely faint test (mere 

 trace). 



One 25 cc. portion of the alcohol solution was diluted with 

 water and extracted four successive times with chloroform, fol- 

 lowed by a single extraction with ether. The chloroform and ether 

 extracts were combined and evaporated to dryness in a platinum 

 dish on the steam bath and later in a hot air oven at 102 C. and 

 the residue weighed. The results indicated the presence of 0.3108 

 gram of organic matter, making a total of 6.2160 grams in the en- 

 tire alcohol extract. 



After the chloroform-ether extraction there remained a dark 

 brown granular insoluble substance. This was filtered off on a 5 

 cm. Buchner funnel and the filter and precipitate used for the 

 determination of nitrogen. The results indicated the presence of 

 0.0010 gram maximum protein nitrogen in this solution, leaving 

 0.1310 gram of non-protein nitrogen in the same extract. 



The negative color tests and the small amount of nitrogen 

 indicate that no protein is present in this soil that is soluble in 

 alcohol. 



Another 25 cc. portion of the alcohol extract was evaporated 

 to dryness on the water-bath in .1 platinum dish and subsequently 

 dried'in an oven at 96 C. with a short final heating at 103 C. The 

 organic matter amounted to 0.6126 gram, making a total content 

 of organic matter in the alcohol solution 12.2520 grams. From the 

 data given it was found that only 1.08 per cent of the organic mat- 

 ter in the 70 per cent alcohol ext -act of the soil was nitrogen. 



b. Extraction with absolute alcohol. A 100 gram portion of 

 the unleached soil was extracted with absolute alcohol for 60 

 hours in a Soxhlet extraction apparatus. The extraction flask had 

 a capacity of 500 cc. and all the joints of the apparatus were ground 

 glass. Several pieces of broken porcelain were placed in the flask 

 to prevent bumping-, as the amount of dissolved organic matter 

 increased. An alundum extraction thimble was used to hold the 



