Wl SCHREINER &• REED-OXIDIZING POWER OF ROOTS 359 



ordinary laboratory distilled water treated with carbon black. The 

 ater was distilled from a copper boiler, condensed in a block-tin 



, and collected in a tin-lined copper tank. This method of 



filiation rives verv good water for ordinary chemical work, but 



worm 



does not free it from 



exert a toxic action as was described by Livingston' » and the 



It has been found that these deleterious substances may 



treating the distilled water with some 



removed oy urea Ling 



finely divided solid which possesses a strong absorbing power such 



as ferric hydrate, or carbon black. The procedure usually followed 



was to shake up a small quantity of the carbon black in the water 

 . ^ n . ". . .i ;,.«,*;«« rsi that, time 



minute 



the water was filtered through ordinary filter paper and was ready 

 for use. This treatment has been found to be as efficient in pro- 



with 



potassium 



permanganate 



.. 



The varieties of wheat used in the experiments were Umi an 

 tarvest Queen." The seeds were germinated on floating perto- 



LlVlNGSTOX 



«wu pmies, accorciing 10 uic mcuiuw ^^ * fmm 



in Bulletin 40 of this Bureau. The seedlings were «^ T f™™ 

 Ae perforated germinating plates to the cultures just as the MS 

 feaf was beginning to emerge from its sheath. 



The plants were held in notches cut in the edge of a cork a 

 Scribed by Livingston. In this way the seed in which en/.™ . 

 *<*e acting upon reserve food materials were kept out 01 _ 

 tions and the enzyme effects observed were ascribable to substances 



• ft 



^mg from the roots. , M ru i 



c 1 . % . ^f i-n cc w r ere used as cui 



Salt-mouth bottles, having a capacit> of 2^0 , wc ^ ^ 



ur e jars, and ten wheat plants were grown in each jar. 



te * two cultures containing 20 wheat plants were ^^J^oftol 



^ comparison was made with an equal number *££££* 



,n Pure distilled water under the same conditions, ai - 1 



** conducted in a greenhouse. During the season ot . 



17 Bur. Soils, U. S. Dept. Agr. Bull. 3 6 - l 9°l- 



,S B 



Ag 



"Plant World 9:13. 1906. 



