March 1, 1904. J Sujjplcmeni to the " Trujjical AgricuUuri:4." 
647 
parnf-ites, v\ithouf, at the same time, exercising 
uny injui'ioLis or retarding effect on growth or on 
the production of fruit. 
From amor.g tlie various substances tested, sul- 
phate of coppf-r (Cu SO4) alone met all the above- 
mentioned requirements. 
The following is an outline of the mode of treat- 
ment of plants rendered immune by the use of 
sulphate of copper : — 
The cucumber and tomato seed was sown and the 
plants grown throughout in a stove, having a 
mean temperature of 75 degrees Fahr., the humi- 
dity varying between 79 degrees and saturation 
point. The potting, watering, spraying, and 
general treatment were left entirely to a gardener, 
and consequently was conducted along the lines 
followed in establishments where the fruit is grown 
forsale Three hundred cucraberseed- 
lings and an equal number of tomato seedlitigs were 
subjected to experiment, fifty of each kind being 
used as check plants. When the seedlings were a 
fortnight old, riie cucumbers were grouped round 
eight large cucumber plants badly attacked by 
Cereospora melonis, Cke., and Vendnjphiuni como- 
sum, and the tomato seedlings were arranged round 
a tomato plant bearing numerous blctches on the 
leaves caused by Cladosporium fuioum. At this 
period the specific course oi treatment commenced, 
which consisted in watering the plants every third 
day with a solution consisting of one part of 
copper in 7;000 parts of water. The check plants, 
which were not watered with the copper solution, 
were indiscriminately mixed with the treated 
plants. The watering was done during the after- 
uoon, and the quantity used for each plant was 
suflScient to so;ik the soil tlioroughly. 
After a month's treatment all the tomato plants 
•were perfectly free from disease. On the other 
hand, one or both cotyledons of thirty-four cucum- 
ber plants showed blotches of the disease. At the 
same time, a considerable number of tiie untreated 
check plants, both cucumbers and tomatoes, were 
badly diseased. 
At this stage both treated plants and checks were 
sprayed with water containing the spores causing 
their respective diseases, and this was continued 
weekly until the end of the experiments. Under 
thisdrastictreatment all the untreated check plants 
were badly diseased during thefollowingtwo weeks. 
After six weeks' treatment with the solution of 
sulphate of copper of the strength indicated above, 
the strength was increased to one part of sulphate 
of copper in H,000 parts of water, and the soil was 
soaked every fourth day until the end of the ex- 
periments, which lasted eleven weeks. At the ex- 
piration of this period, both tomato and cucumber 
plants were bearing a good crop of well-growu 
mature fruit. 
Not a single one of the tomato plants treated 
with the sulphate of copper solution showed a 
trace of disease ; and in the case of the treated 
cucumber plants the disease never extended beyond 
the cotyledons, and this notwithstanding the iact 
that badly-di.-eated plants were growing amongst 
the treated plants during the whole period. . , 
It now simply remained to ascertain whether any 
of the copper takeu up by the roots of the plants 
had been deposited in the fruit. Specimens of 
tomatoes and cucumbers borne by the treated 
plants were examined in the Government Labora- 
tory by Dr. Thorpe, C.B., F.B.S., and he re- 
ported that there was no evidence that the amounts 
of copper present were sensibly greater than are 
found in the fruits obtained from the non-treated 
plant?!. Tlie p;iper concludes with 
PRACTICAL DIRECTIONS FOR TREATMENT. 
Commence watering cucumbers and tomatoes, 
when a fortnight old, every third day with a 
solution consisting of 1 oz. of sulplinte of copper 
dissolved in 59 gallons of water. After treating 
for six weeks as above, commence watering every 
fourth day with a solution consisting of 1 oz. of 
sulphate of copper in 3-5 gallons of water. The 
sulphate of copper should be pure, and rain water 
should be u;ed if possible. 
-5, 
THE PAPAW FRUIT. 
We know a good deal about the papaw orp'ipaj'a 
(erroneously called "popoy" by some people) 
seeing that the fruit is so common with us, but 
the following article from the American Journal 
of Pharmacy tells us a lot that we fancy most 
people have never heard before : — 
Quite universal is the knowledge of the unique 
properly that has given to the papaw its world- 
wide famp,viz., the power of its milky juice to 
soften and dissolve tough meat. The statement 
has passed current in our journals that the 
emanations from this tree will dissolve and digest 
albumen, and that it is the custom of natives to 
hang meat and chickens ia the branches of a tree 
to render them tetider and edible. The natives 
often go further than this ; they state that if male 
animals browse under the papaw tree, they there- 
by become emasculated. If we compare this 
statement with the alleged property of the roots 
as a generative tonic, we shall have a marvellous 
combination of an aphrodisiac and an aaapbrodisiac 
in the same plant. 
It is needless to urge that such stories are 
exaggerations of the pepsin like properties of the 
fruit. 
The native usee of the papaw are numerous and 
varied. The bark is u^ed in the manufacture of 
ropes ; the fruit ia edible, and according to the 
local conditions, may be sweet, refreshing, and 
agreeable, or in other localities it is sickly, sweet, 
and insipid. The fruit finds a large consumption 
by the natives, and is considered very nutritious. 
At the corner of a sugar-cane field, where the 
ragged canes bend over in a wild green, brown, and 
yellow tangle, there will be stauaing a papaw-tree, 
and, if the time of the papaw tree has quite come, 
beneath the tree will be assembled a half-dozen 
negroes. 
The ripe fruit is eaten as we eat melons. Salt 
enhances the flavour, and some users add sugar. 
The melons must be perfectly ripe when eateu 
raw, as the green fruit contains a strongly marked 
acrid principle. The colour of the ripe fruit is 
more or less that of our very yellow musk-melon. 
The sweetness of its resinous, pulpy juice clings to 
the touguy and remains prevalent for some hours, 
