8I2 
Journal of Agricultural Research 
Vol. XXIV, No. 9 
we will reserve further discussion of the matter until the results of experi¬ 
ments in sand, in which the culture solution contained large amounts of 
sodium chlorid, have been reported. 
The percentages of calcium (Ca) in the ash of the leaves and shoots of 
the soil culture were higher than for the sand cultures; the trunk and 
roots contained, approximately, the same percentages respectively in all 
three cultures. The calcium in the total ash varied from i8 to 30 per 
cent in the various parts in both sand and soil cultures. The percentage 
content of calcium in the leaves of the sand cultures was considerably 
lower than that of the soil culture, while the potassium relation was the 
reverse of this. These as well as previous analyses have shown that citrus 
trees have a large capacity for absorbing calcium. Coville with the aid 
of Breazeale (3) has reported the percentage of calcium oxid in the ash 
of other trees as compared with that of citrus. They have found that the 
percentage of CaO in dried freshly fallen leaves ranged from 1.73 per 
cent in Red Oak (Quercus rubra) ^ to 6.77 per cent in orange (Citrus 
aurantiurn) with 10 other species of forest trees having intermediate 
values, basswood (Tilia Americana) attaining the second highest per¬ 
centage, or 4.50 per cent. 
It is of interest to note the consistently low percentage of magnesium 
(Mg) in the ash of the various parts of the trees in the sand and soil 
cultures. 
The percentage of aluminum (Al) in the ash of the trunk, root, and 
rootlets is greater than that of the leaves or shoots. The small per¬ 
centage of aluminum in the ash of the leaves and shoots indicates that 
these parts of the trees were thoroughly cleaned from adhering dust. 
As the nutrient medium used in the sand cultures contained no aluminum, 
we would expect the trees in these cultures to contain but little. 
The percentage of iron (Fe) in the ash of the various parts of the three 
trees ranged from 0.2 to 0.9 per cent. The percentage of manganese 
(Mh) was usually very low. The percentage of chlorin (Cl) in the ash 
ranged usually below 1.2 per cent. The percentage of sulphate (SO4) 
present in the ash was considerably higher than that of chlorin, being 
2 to 5 per cent, although the rootlets in the sand culture showed over 8 
per cent. 
The percentage of phosphate (PO4) in the ash of the shoots was con¬ 
siderably higher in both the sand and soil cultures than that of the 
leaves, with a decrease in the trunks and an increase in the roots. The 
ash of the rootlets in the sand cultures contained about 17 per cent 
phosphate as compared with 8 per cent in the ash of the shoots and 4 
per cent in that of the leaves. 
It is of interest to note the high percentage content of K, Ca, and 
PO4 in the ash of the rootlets in the sand culture, constituting over 50 
per cent of the ash of the rootlets, with a marked reduction in the per¬ 
centage of CO3. The perceiftage of silica-free ash in the rootlets ap¬ 
proaches that in the leaves and is much greater than that in the shoots, 
trunk, or root. 
The percentage of PO4 in the ash of rootlets was greater than for any 
other portion of the tree. The largest percentages of mineral constitu¬ 
ents appear to be deposited in those parts of the tree in which the assimi- 
latory processes are most active. 
The sap of citrus leaves possesses the power to neutralize considerable 
base. Kelley and Cummins (6) have shown that 10 cc. of normal leaf 
sap required 3 cc. of N/io alkali for neutralization, while mottle-leaf 
