122 
FLORIDA STATE HORTICULTURAL SOCIETY. 
chapter of the agricultural chemistry of 
the future, for which only scattered and 
unharmonized data have been gathered, 
the tolerance of plants for unsuitable 
fertilizers. 
To illustrate: Some twenty-five years 
ago when I first began orange culture 
on my own account, when the spring 
growth was pretty well matured, some 
time in April, I dumped about four quarts 
of brine from a mackerel kit near the 
trunk of an orange tree that could carry 
a box of oranges, as an experiment, to 
see what effect it would have as a fer¬ 
tilizer. 
In a week's time all the leaves had 
dropped from that tree and most of the 
new growth was dying. It was two 
months before the tree had got back half 
its foliage again and the effect was as 
bad as a severe freeze. This was a most 
striking example of the tolerance of an 
orange tree for chlorine and soda. I say 
chlorine and soda because it is a well 
known chemical fact that there are points 
of saturation in common salt solutions 
in which the chlorine and soda are in 
very loose combination and there might 
be some separation in the sap of a tree. 
Some people have an idea that plant 
rootlets have considerable power of se¬ 
lection of the solutions with which they 
come in contact and take only what they 
need or is beneficial. This experiment 
convinced me plants have to take what¬ 
ever is offered them in the soil water 
and that plants with green foliage or in 
a growing condition are continually sus¬ 
ceptible to sap poisoning. 
In the case of the orange tree and the 
brine it is evident that as the brine as¬ 
cended in the sap to the leaves and was 
evaporated from them a point of satura¬ 
tion or crystalization was reached that 
killed the life principles of the sap and 
the leaves dropped off. 
In this most simple case a chemical 
analysis of the leaves for salt and a com¬ 
putation of the total foliage on the tree 
would have determined the extreme tol¬ 
erance of a tree of that size for chloride 
of sodium. After the leaves were all 
fallen there still remained the salt solu¬ 
tion in the twigs, branches, trunk and 
roots. As the fresh growth of twigs had 
an evaporation function partly as great 
as the leaves the solution was strong 
enough to kill most of them also. 
The solution in the branches, trunk 
and roots being weakest of all had proba¬ 
bly to be mostly excreted by the roots 
and the solution in the soil leached out 
at one-half the cost of imported nitrate 
by rains before the tree could grow again. 
This brings us to the root excretions of 
plants. 
Root excretions of plants have long 
been recognized-but so far as I know no 
exhaustive experiments have been con¬ 
ducted to determine their character and 
effects. It is well known that many 
crops cannot be grown successively on 
the same ground without losing so much 
vigor as to be unprofitable or suffering 
from disease. 
In my opinion the study of diseases has 
drawn attention away from the specific 
salts and humic acids these plants may 
leave in the soil that are poisonous to 
succeeding crops of the same variety. 
There is also, of course, the natural 
acidity of some soils that is detrimental 
to many crops unless corrected with lime 
and it may be lime would be a good ap¬ 
plication for root excretions. Lime has 
succeeded in some cases where tomatoes 
grown successively nave been affected 
with blight. Tomatoes will not do well 
