60 BOTANICAL GAZETTE [JANUARY 
EI. 
DATA FOR EXPERIMENT V. 
Culture no. Meatum ao) aos 
on ek er : aapedel st = mi sie POO cr. ne ote ewe ASG ian a |! —codnape 
ee Mise sachs wean pete Do. ROC oe tee ae 471 = 200 
Bcad mops tae Extract 3 Cet clay, POOR sx ccsta vec P srs WOT scan Wy eed ieees 
AD cess ae ney th Sica] Oe UE DORN LEE OTOO 5. ooo. ssa Jonnie oh aces Sesh maee 477 “ize? 
[Ser eS eee Extract of Leonardtown loam, good.. a! ee eee ee 
irae, ogee Ceara SN TRMOTEE S Scw re emo ope eee 407 +13.4 
ype eres Ea ract of ie te loam, poor.. DRL ea «tte average 
Buea sae Do carbon filtered si. i465 sien ees 349 + 28.7 
was not improved by treatment with carbon where the latter is filtered 
out. All the others were im- 
proved, although the improve- 
ment in the case of good Leon- 
ardtown loam was not as marked 
as that in case of the poor. The 
leaf development and _ general 
appearance of the plants were 
essentially in proportion to their 
transpiration. The roots showed 
__ the same acceleration with carbon 
~ treatment and filtering that had 
been observed in experiments in 
which the solid was left in the 
solution. Fig. 3 shows the roots 
of cultures nos. 1, 2, 3 and 4. 
es 
part at least ‘of the injurious 
matter which is removed by car- 
bon black is in the soil extract 
at the start. 
: A number of experiments were 
: glee pede igi ee grown carried out, using water twice 
Ae ee be ed water; 2,thesame, redistilled, first from potassium 
dichromate and sulfuric acid, then 
from alkaline eens permanganate, both in glass boilers, con- 
