May SO, 18S9. J 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
435 
trees :—1, Frost rupturing the tissue locally, as in the example 
figured ; and when the soil is good and seasons genial the parts heal 
naturally. 2, Cold, heavy, and poor soil, as in Mr. Tonks’ case, the 
remedy then being amelioration of the staple and enrichment, as 
was carried out with such excellent results. 3, Corrosive matter in 
the soil, such as a large percentage of iron. “M. T.” (page 108) 
narrated an example of this with a cure for a time, and I have had 
the most conclusive proof that he is right. I have seen acres of 
trees ruined through an excess of iron in the land, and it fell to my 
lot to remove such of them as could be restored. About one in 
-fifty was selected for experiment, and some of these are now fine 
^bearing trees. The roots of the remainder were practically eaten 
away, and the branches were in much the same condition. But 
there was much more than a “ trace,” that is a measureless 
quantity, of iron in the soil. I should not in the least object to 
:2 or 3 per cent., but in the case mentioned there was at the least 
ten times the quantity, and tons have been extracted for commercial 
purposes. 
I have thus learned by somewhat long and varied experience that 
it is not safe to dogmatise on this subject of canker, and I think 
neither the insect theory nor the special food theory has more than 
local application. I suspect they cannot be connected with the 
Impney case, and I shall be very much surprised if they can be 
shown to have anything to do with the condition of three trees in 
Dr. Hogg’s garden. They are all of one variety, Dumelow’s 
Seedling, in a row across a narrow strip of land. One of them is 
practically ruined, one partially attacked, the main stem being eaten 
half through where no ligature has ever been, and the remaining 
tree is clean. What about the special wants of special varieties, 
or the preferences of insects of one variety over another in such a 
«case as this ? There was no difficulty in discovering insects in the 
Impney specimen when examined in London some days after it had 
fig. 70. 
been cut off the tree, and I have seen many like them in decaying 
wood without canker ; and as the healing process is apparent in the 
wound figured it would be at least as reasonable to say they were 
the cause of the cure as of the disease. We shall perhaps hear what 
the authorities say ; it is wonderful what can be proved in argument 
by able men. . , , 
Just another word on canker in the main stems or standard 
Apples on so-called Crab stocks. Not half of them are raised from 
FIG. 71. 
the English Crab, but from the “ marc ” or refuse from cider mills. 
These differ in variety and probably in hardiness; and I may 
venture to suggest the possibility of there being less canker in the 
stems if these were veritable hardy English Crabs. 
It will be seen by the figures how the stem thickened above the 
canker in consequence of the arrest of the returning sap. The 
healthy layers may be perceived creeping down and over the gan¬ 
grened part in fig. 70, and the free growth of the branch was due to 
the absence of canker from one side, fig. 71, and through this narrow 
channel the sap flowed in sufficient quantity, for the branch above 
the affected part did not differ in length, strength, or character 
from the others on the tree.—W. 
GARDEN ALLOTMENTS—THEIR ADVANTAGES 
AND UTILISATION. 
[Read at Nottingham by Mr. J. Wright.] 
(Continued from page 415.') 
Facts About Manures. 
We next pass on to see what must be added to the soil in the 
form of manure, for it is useless expecting full crops if the ground 
is not charged with fertility. Provide this, and have the land in a 
free, workable state, never allowing a weed to be seen, and every 
useful crop sown or planted at the right time will give a good 
return to the cultivator. What is manure ? Heaps of fermenting 
litter and decaying refuse from stables, cow houses, and piggeries 
is by some exclusively regarded as manure. This is called natural 
manure. Some of it is valuable, much of little value. It is good 
for what it contains. I do not want to be scientific, but can only 
make the matter plain by using what some of you may perhaps call 
fancy words. Well, I will only employ three. Natural manure, 
then, must contain nitrogen, phosphoric acid, and potash. If it 
