610 COKTRIBUTIOXS TO OUR KXOWLEDGK OF SOIL-FERTILITY, iii., 



of vegetable matter, and tliere are probably man}' forms included 

 in tlie general name of humus. (Jne of these, xylan, has been 

 detected by Schreiner and Shorey* b}' means of its hydrolytic 

 derivative, xylose. Galactans, so far as I know, have never been 

 detected in soils. 



A rich, broNvn orchard soil from the Kurrajong was selected as 

 being most likely to yield a slime in quantity, and the method of 

 extraction was that employed by me in obtaining gum from 

 bacterial slimes. The soil was mixed with an equal volume of 

 water, and lieated first on the water-bath, and then in the auto- 

 clave at three atmospheres' pressure for some hours. The solu- 

 tion was filtered, and precipitated with an excess of alcohol. 

 Both the precipitate and the alcoholic solution were reserved for 

 examination. 



The j^recipitate was treated in water, and again precipitated 

 with alcohol. It consisted of a gelatinous precipitate of a pale 

 buff colour, which l)ecame black upon drying. Both the precipi- 

 tate and the alcohol soluble matter were boiled with 5% sulphuric 

 acid for some hours, when furfural was detected, and reducino- 

 bodies were produced. In each case, a blackish-l)rown, insoluble, 

 humic powder was slowly precipitated. 



The acid solutions were neutralised with barium carbonate, 

 evaporated to dryness, picked up with water, filtered, and heated 

 with phenylh^drazine mixture. The resulting osazones, obtained 

 as hot-insoluble and cold-insoluble precipitates from time to time 

 as heating progressed, were purified with water, alcohol or chlo- 

 roform, as occasion suggested, and fractionated into parts of 

 similar melting {)oint, and crystallised again and again from 

 alcohol of various strengths, and from water. 



The final products of the separation were found to be gluco- 

 sazone, galactosazone, and an osazone melting at ]74°C. The.se 

 were obtained both from the alcohol-insoluble gum, and from the 

 alcoholic filtrate. Partial hydrolysis had evidently taken place 

 during the autoclave treatment. 



* IJiiieau of .Soil.s. bulletin No.7-4, Dec. 19I0. 



