Centralized District Schools. Grafting Nut Trees. 
Vol. LYIII. No. 2568. NEW YORK, APRIL 15, 1899. $1 PER YEAR. 
good time. In this case, the leaves are scorched on 
bright, sunshiny days, but the burning does no harm 
to the trees, as the leaves are nearly ready to fall any¬ 
way. We usually begin our outdoor work about the 
middle of September. We have, also, done some 
fumigating in March ; in fact, I am just preparing to 
begin some work the first week in April.” 
“ I understood you to say that the gas is lighter 
than air.” 
“ That is true, and the gas will replace the air in 
any inclosure, on account of its penetrating property. 
It diffuses so rapidly that it will fill even the lowest 
corner in a room in a moment. You can see from the 
position of that cat, how quickly and suddenly she 
was killed. The gas will readily pass out through an 
open door, window, or a flue put at the top of the 
room.” 
At the nursery of Peters Brothers, Wesley, Md., I 
found a fumigating house with a wooden flue running 
from the top so that the gas would pass away at the 
top of the building. One reason why this flue was 
built was because the inner door or window opens 
into the packing shed, and it was not thought advisa¬ 
ble to let the gas out where the packers were at work. 
Therefore, the slide in the flue may be opened, and 
the gas will pass harmlessly away into the air. All 
agreed that it is perfectly safe to enter a house or 
room after it has been open for 10 to 15 minutes. No 
one is permitted to enter under 10 minutes. 
A Perfect Remedy. —“ I notice that there is no 
change whatever in the appearance of those trees. I 
had an idea that, possibly, some chemical could be put 
with the cyanide so that the trees might be bleached 
harmlessly, and thus permit the buyer to know that 
they had actually been fumigated.” 
“ This gas has no bleaching effect upon the trees, 
and there is no absolute way of knowing, by its appear¬ 
ance, whether a tree has been fumigated or not. I 
do not know of any chemical or combination of chemi¬ 
cals that could be used with the gas to leave a harm¬ 
less residue, or bleach the tree. The buyer has only 
the guaranteed certificate of the nurseryman to show 
that the trees have actually been fumigated.” 
“ You do not know, then, of any gas, that will do 
the work as effectively as the hydrocyanic ?” 
“ No. In fact, it has all the properties we require, 
and it would be hard, if not impossible, to find a bet¬ 
ter. It is cheap, easy to apply, quick to diffuse, with 
sure killing properties to animal life. It is practically 
a perfect remedy. Bisulphide of carbon cannot be 
used with any degree of success. It would take too 
long to fill an inclosure with the gas, and it would re¬ 
quire from 10 to 24 hours for a thorough fumigation. 
The cost is, also, greater, the gas is 
not so deadly, and will not so quick¬ 
ly diff use itself as the hydrocyanic. 
Many other poisonous gases have 
been tried, but none has been found 
so effective.” 
“ Can this gas be used for many 
other insects ? ” 
‘ 4 1 feel very sure that it is destined 
to play a most important part in in¬ 
sect destruction. As I said before, 
we are now working with the Straw¬ 
berry aphis. As yet, I cannot make 
any positive statements, as we wish 
to know more about the effect of 
the gas upon the plant itself. The 
Black peach-aphis was very de¬ 
structive last season. The gas will 
make nearly a perfect remedy for 
this insect, as it winters as an adult 
upon the roots. Every one can be 
easily destroyed by fumigation in 
the house, before the trees are set 
out.” 
Mr. Harrison told me that they 
fumigate 10 or a dozen times a day. 
It is easy to back a wagon right into 
the room, take out the tongue, and 
shut the doors. The cost of one 
charge is about 14 cents. To do the 
work effectively, the cost would be 
the same for one tree as for 10,000, 
since a certain amount of cyanide 
would be needed in any case to fill 
the room with the gas. 
Trees and Their Food. —The 
trees we saw fumigated were peach. 
This part of Maryland is noted for 
its production of peach trees. The 
Harrison and the Peters firms pro¬ 
duce over a million and a half trees 
each year. The warm, open soil, when well fed, gives 
a fine root to the peach. Apples and pears do better 
on a heavier soil, but the peach loves a hot brick at 
its feet. 
I was surprised to hear Mr. Harrison say that there 
is a good demand this year for the Crosby peach. 
This variety has not been in very good standing for 
the past few years, but this year certain growers are 
after it again. The chief demand is from western 
Maryland, where it is said the Crosby grows to per¬ 
fection, with good size and appearance and an ex¬ 
quisite flavor. The heaviest demand is for Elberta 
and peaches of that type. Carman is considered a 
very promising variety. Down in this country, the 
Kieffer pear is a highly respected citizen. The trees 
are hardy and vigorous, and less likely to be injured 
by the scale than most others. The fruit grows as 
JAPAN CHESTNUT TREE, PARAGON. Fig. 112. See Rubalisms, Page 280. 
HOW MARYLAND FIGHTS SAN JOSE SCALE. 
FUMIGATION IN THE NURSERY. 
How and Why It Is Done. 
[editorial correspondence.] 
Part II. 
Sure To Kill.— The doors of the fumigating room 
had been open for about 15 minutes when we returned. 
A faint odor of peach pits still lingered in the room. 
The trees were unchanged in appearance, but the 
cat lay dead as a stake. She had barely reached the 
top of the pile, the first whiff of the gas evidently 
killing her. The whole thing was so simple, that one 
is at first inclined to wonder whether it is thoroughly 
effective. 
“ Are you absolutely sure that this gas will kill the 
scale ?” 
“ There is no question about it,” said Prof. Johnson. 
“ If this gas is properly generated 
and handled, it will destroy every 
scale upon the tree, whether there 
be 1 or 10,000. In 1897 we treated 
young trees of pear, peach, plum, 
cherry and apple. They were liter¬ 
ally covered with the scale when we 
put them into the fumigating house. 
We set them where we could watch 
them every week. Not a living insect 
has been observed on those trees 
since. They were alive with the 
scale before we fumigated them, and 
they have now been growing for 
two seasons. We duplicated these 
tests in the Spring of 1898, with the 
same results. We also took several 
badly infested trees, and placed 
them on the floor at the bottom of 
5,000 nursery trees in one house. 
These were watched closely during 
1898, and not a single insect devel¬ 
oped. We are now absolutely cer¬ 
tain that this terrible gas will kill 
every insect, if by chance they should 
be upon a tree. You may state 
positively that, when properly gen¬ 
erated and applied, no breathing 
thing can escape from this gas.” 
“But is there not danger of in¬ 
juring the roots of the trees ? ” 
“ No, you cannot possibly injure 
the roots of any kind of fruit trees 
with this gas. The chemicals would 
have to be used about eight times 
the standard strength, to affect them 
in any way. At the strength we 
now use the gas, trees should never 
be left in a house for less than half 
an hour. You may safely leave them 
for hours, or even overnight, with¬ 
out any injurious effect. Trees can, also, be fumigated 
two or even three times, without being injured, 
although once is sufficient.” 
Injury to Buds.—“ But would not the gas injure 
the buds after they have started ?” 
“ Yes, that would cause injury. The gas should be 
used on nursery stock only, when the trees are dor¬ 
mant, either in the Fall or Spring. This can be ac¬ 
complished readily, as nurserymen do not, as a rule, 
handle their trees after the buds begin to unfold. 
Most nursery stock is dug, fumigated and heeled in, 
where it can be conveniently packed later.” 
“When, then, is the best time to attempt to fumi¬ 
gate small trees outdoors ? ” 
“My outdoor fumigating is done mostly in the Fall 
and Winter. After the function of the foliage has 
been performed, and just before the leaves fall, is a 
