4 
CAROLINE RUMBOLD 
grams for trees with 16-25 cm. diameter, cured apple trees of disease and 
insects. Mokrjetsky stated that he was carrying on more experiments as 
he beheved that the fertilization of plants with such injected salts often 
cured them at the same time of diseases. 
The best reports on tree injection so far printed are the Russian. Most 
of the experiments were made in the Crimea. Here many of the fruit trees 
appear to suffer from malnutrition, according to Mokrjetsky (14), and the 
iron sulphate appeared to act as a most efficient fertilizer. The dry, hot 
summer climate of this region favored the rapid consumption and transfer 
of the injected solutions, to which the trees reacted in a striking manner. 
No reports have been found as to the length of time the injected iron sulphate 
acts as a fertilizer, except a statement by Mokrjetsky that in the spring 
following the injection the buds on the fruit trees were numerous and large. 
The Russian experimenters appear to have stopped, unfortunately, before 
they had concluded their work. In 191 2 the writer received a letter from 
Shevyrev saying that he was unable to continue the injections and hoped 
that the work would be carried on in this country. 
A series of short papers by German, French, and American workers 
followed Shevyrev's publications. 
Roth (15) in 1896 described a method and apparatus for injecting trees. 
Mangin (16) in 1898 unfavorably criticized plant injection, especially 
the idea that grape vines could be protected from fungi by the injection of 
salts. He regarded plant injection impracticable in agriculture. 
Goff (17) found the injection of water into the roots of newly transplanted 
trees to be beneficial. He described his apparatus and method of injection. 
His experiments showed that this treatment hastened the initial growth of 
the trees. 
Bolley (18) in three reports described experiments in stimulating tree 
growth by injecting liquid solutions into the trunk. He successfully treated 
diseased apple and plum trees with a formaldehyde solution of 1/2 to 2 
parts per 1000 of water. He reported that the effect of injected solutions 
on parasitic diseases was inconclusive. 
Simon (19) reported that he successfully injected apple and peach trees, 
grape vines, and potatoes. Water solutions of purin and potassium nitrate 
and nutrient solutions were used. Copper sulphate injected into grape 
vines was at first injurious, but later the vines produced new leaves free 
from fungi. 
Fron (20), using Simon's method of injection, treated pear trees with 
solutions of iron sulphate and calcium nitrate. The vigor of the trees 
appeared to be increased, but the improvement was confined to portions of 
the trees only. He believed this method of little practical value in fruit 
culture. 
Coffigniez (21) experimented about the same time with iron sulphate 
and fruit trees in the control of fungus diseases. 
