Ini Green Plants from certain Organic Compounds. 



17B 



" Humus Extract." 

 Experiments with Water Plants. 



(Method and apparatus as described on pp. 155 — 156). 



Solution used. 



Plants. 



Results. 



A. The culture solu- 

 tion diluted with 

 twice its volume of 

 j distilled water + 

 " humus extract " 



Sparganium natans (parts of 4 

 plants) 



Callitriche aquatica 



No starch formed. Plants 

 not injured after 10 days. 

 No bubbles of gas evolved 

 in bright sunlight after 

 six hours. 



B. Some humus-con- 

 taining soil which 

 had been heated to 

 low red-heat (10 

 hours) in a " muffle' ' 

 and cooled in a de- 

 siccator added to 

 above solution just 

 before transferring 

 the plant to solu- 

 tion 



Callitriche aquatica 



Ditto ditto 



No. 13. Experiments with the " Humus-like " product of Alkalies on 



Cane- Sugar.* 



Cane-sugar (saccharon)t was boiled with strong solution of KOH 

 for half an hour, and the whole solution diluted with water and then 

 acidified with HC1, which causes the separation of flocculent brown 

 " humus-like " substances. The precipitate was washed with dilute 

 acid, dried, and then boiled with water ; the aqueous extract so pre- 

 pared was used in these experiments after filtering through paper. 



The above aqueous extract contained about 2 per cent, of solid sub- 

 stances. 



* The chemical nature of these brown "humus-like" substances is very little 

 known, but they are generally assumed by chemists to be closely related to the 

 chief constituents of natural " humus," which must be chiefly derived from the 

 decomposition of cellulose and ligneous matter. (Compare Beilstein, ' Handb. d. 

 Org. Chem.,' 2nd Edition. — " Huminsubstanz.") 



f Compare Conrad and G-uthzeit, in ' Berichte Deutsch. Chem. G-esell.,' 1885, 

 p. 439. 



o 2 



