93 
Dr. Featherstonhaugh adds the following testimonial: “We 
had the satisfaction of assisting, during the present month, to- 
gether with Professor Del Rio, at a repetition of curious exper- 
iments on vegetable substances, with vegetable and mineral poi- 
sons, conducted by Dr. Harlan, assisted by Dr. Moore, in the 
garden of the Philadelphia Alms-house Infirmary. Each of 
the poisons were separately introduced into the circulation of 
individual plants, by incisions made in the stems, under the 
leaves, and by similar, sep2irate applications of them to their 
roots ; by infusions, and by powder also, in the case of arsenic. 
In some instances the poisons were placed round the roots only, 
viz. corrosive sublimate, arsenic, sp. turpentine, and oil of tobacco. 
In none of these instances was any of the plants poisoned. One 
of tlie young geraniums faded after constant impregnation, for 
three days, of the earth about its roots, but this is evidently at- 
tributable to its soil being rendered unfit for the support of veg- 
etable life. We must therefore adhere to the reasonable opinion, 
that plants have the property of segregating from the soil or 
atmosphere those principles which are proper for their healthy 
state, and of rejecting those which are injurious to their organi- 
zation. If plants yield to the deleterious influence of those 
principles which are injurious to other organized bodies, it is 
because — as in the case of the young geranium — they cannot 
appropriate those salutary principles, upon which their existence 
depends, and which enables them to excercise their natural 
functions, one of which is, to reject that which is injurious to 
,.Jbcm. We speak now of the circulation of plants, and not of 
the mechanical application of poison to their parts. Oil of tur- 
pentine applied several days to the bark of many trees, and es- 
pecially the linden tree, will soften and eventually destroy the 
part ; but the experiments tried with the balsamina, or lady- 
slipper, the palma Christi, the cabbage, and tobacco plant, 
whose roots were liberally supplied with spirits of turpentine, 
prove that it did not affect them through their circulation.” 
We do not entertain a single doubt of the correctness of Dr. 
Harlan’s statement of experiments, here set forth; but, judging 
from these alone, we cannot admit the justice of the Doctor’s 
conclusion — namely “ That the experiments detailed by Pro- 
fessor Princep are erroneous.” As far as Dr. Harlan has de- 
tailed HIS experiments they cannot be taken as a total disproof 
H7 iCCTAEIUM. 
