CONTENTS 
PAGE 
Review of literature concerning loss of nitrogen by growing plants... 7 
meee ol thespresent experiments. .... 006... 6. eee Se ec eee 14 
| _LETLAOG! WSSGLS . 5. 5 cae IRE Bem ee em 14 
re etlans metal lite el Onlemp aye see sire sc haces ssa ec cic sh ene 16) 
ERC ananione@iethe TASKS .:. ..% incase 2 de aod nue Gielen bo ee es 16 
Ree TRGOMOTOM 5 so osc fake hc ak ol a ge Ry Ok eee 16 
Seunugecotathe plants. ..........<..8 Nie Date tee ar rece ne et A ne i 
Rieiwyestmmenune plants 6-80.05. sss wes ele nae peso eb betas 17 
Analysis of nutrient solutions and residues in bottom of flasks.... 17 
Tests for the presence of organic nitrogen in nutrient solutions in which 
miamcromseveraiukinds had grown. -). 006 000.¢. 06052. 18 
Organic nitrogen present in nutrient solutions at successive stages in 
STMT OUAMOMIMMNALZOR 562). 2 sss s- 5 Ss eects Sa ae ae es ee ets D8) 
Total organic matter present in nutrient solutions in which maize 
Pernice ar bOmO wi Mr et) eo an eee ie ie ee eee oie 31 
Reducing and oxidizing substances liberated by plant roots. ........ 34 
BePivenemmotmliccratune <..% << 8) s.cs asec ences cn cede es 35 
Tests for reducing and oxidizing substances liberated by plant 
TROOUESIs o 9.0" DRO Ga IBG EON: or ESTAR Shearer ae ar dem eee 36 
ved M@elmeesUSlAN CES east or eos sence sti see ee ee AX 
VeEGUCHOMVOL MILTATES. a Wa. ine ee Ns ak eee: OM 
Oxtaizmorsulstances eco ps Aen ence ek alas jaa 39 
Possible coexistence of oxidizing and reducing substances... 40 
Nature of oxidizing and reducing substances.............. A() 
 LLELOSEP Sw oo 8 cach] eS ae ee ee ec reer cae ing org 40 
—._LEVESRE CLANS 5g eae tp Pec Ne A ge ee 43 
