288 
Solutions from sound and blighted pears were also tested 
with Soleil’s saccharimeter, but without securing suffic- 
1ently uniform conditions to make the results worth record- 
ing. All that need be said is that both solutions were 
found to_be levo-rotatory, with a less percentage of sugar 
in the solution from blighted fruit. 
Can the common expression of horticulturists, that blight 
is connected with a ‘‘ poison” or ‘‘ poisonous sap,” be taken 
literally? To find an answer to this question, freshly and 
thoroughly blighted Bartlett pears (inoculated July 6 and 
gathered six days after) were tested for ptomaines, with 
Mr. Ladd’s assistance. Two such pears were digested with 
alcohol acidulated with tartaric acid, then with pure alcohol, 
the two solutions put together, filtered, evaporated to a 
syrup, and redissolved in ether. The following reagents 
were then successively employed—gallic acid, iodine in 
iodide of potassium, ferric potassic-cyanide, concentrated’ 
sulphuric acid, platinic chloride, potassio-mercuric iodide, 
and phospho-molybdic acid—without securing any ptomaine: 
reaction. It is therefore sufficiently proven that no ‘real 
poison exists in connection with this disease. 
blight bacteria in dead matter.—Experiments have shown 
that the germs retain their vitality for a considerable time 
in limbs cut from the tree and thrown upon the ground. 
The most interesting result came from cultures started with 
the inner bark of a blighted limb that was cut from the 
tree in midsummer and thrown into a tank of water in the 
garden. In the fall the water was drained off, but the 
sediment remained moist till spring, the examination taking 
place the middle of April. After a period of nine months 
under these circumstances the bacteria were found to be 
alive, and in a growing condition. 
A solution was made by treating soil with boiling water, 
filtering and sterilizing. This gave a nutritive solution in 
which the bacteria grew with moderate readiness, produc- 
ing a pellicle and zodglosa. A culture of this kind started 
with germs from the quince, reproduced the disease in a 
Bartlett pear tree by inoculation. 
The two facts that blight bacteria may retain their vigor 
in dead limbs from one season to another, and that they 
can thrive in garden soil, make it evident that itis the part. 
of cautious treatment to burn all blighted limbs when taken 
from the trees, and to remove affected limbs before they 
drop the exudation that may convey the germs to the soil. 
Index to literature of pear blight.—Probably no disease of 
plants has been more written about in America than the 
pees blight. The list of authors, which is being prepared 
y the writer, already contains several hundred names, al- 
though still quite incomplete. Taking the whole range of 
