Arsenical Poisoning of Fruit Trees. 
39 
According to this analysis, the amount of phosphoric acid pres¬ 
ent is scarcely good but the supply of other plant food is very fair 
That this soil contains arsenic is assumed as the orchard has been 
sprayed for years. The carbonic acid, CCh, present corresponds 
to about 19.38 per cent, of carbonate of lime. The preceding is a 
surface soil. 
One of these marly subsoils had the following composition: 
ANALYSIS OF MARLY SUBSOIL. 
Insoluble . oo.bbd 
Soluble Silica . 2.86G 
Chlorin . trace 
Sulfuric acid . trace 
Carbonic acid . 12.444 
Sodic oxid .,.. 0.390 
Potassic oxid . 0.360 
Calcic oxid . 16.538 
Magnesic oxid . 2.438 
Ferric oxid . 3.428 
Aluminic oxid . 1.326 
Manganic oxid (br) . 0.260 
100.033 
We have here about 28.28 per cent, of carbonate of lime or 
marl. This subsoil was taken at a depth of twenty-three inches, and 
though representing the subsoil of a sprayed orchard I deemed it of 
sufficient interest to determine the arsenic that it might contain and 
found 15.33 parts arsenic, calculated as arsenic acid, per million. I 
scarcely think that the spray applied to the trees would find its way 
down into this marl. This orchard had been given surface cultivation 
only, still I acknowledge the question as an open one whether this 
arsenic is an original constitutent of the marl or an adventitious 
one arising from the practice of spraying. Personally I believe that 
the marl itself has always contained the arsenic. 
I will give an analysis of a marl from still another place. This 
sample was not taken in the orchard itself but from an adjoining piece 
of land belonging to the same owner as the orchard. I will state that 
this orchard showed a pronounced case of rosette. 
ANALYSIS OF A MARL. 
Insoluble . 24.098 
Soluble Silica . 8.269 
Sulfuric acid . 0.350 
Carbonic acid . 27.115 
Calcic oxid . 34.525 
Magnesic oxid . 2.942 
Iron and Aluminic oxid . 1.960 
Manganic oxid (br) . 0.180 
99.439 
