Dec. 1, 1900.] THE TROPICAL AGRICULTURIST. 
383 
At present, no mention is made of other other than 
the pod disease in Trinidad, but the fact of a 
parasitic JVcrfn'a being present, necessitates the prompt 
execution of measures calculated to prevent the 
parasite from exteudiug its ravages." 
It vfill be seen therefore that the Kew authorities 
were of opinion that the Phytophtkora wa.s the csLUse 
of the destruction of the pods, and later evidence 
appears to coulirm this view. 
There is however considerable danger to be appre- 
hended from the spread of Nectria, or second species 
discovered. 
Subsequently another, and yet un-named, species 
of Nectiia has been found destroying the bark of 
cacao trees in Trinidad. Thus there are three dis- 
tinct fungi, which are known to attack cacao trees 
in Trinidad. 
It has been found that Phytophthora attacks pods 
at all stages of their development and frequently 
when partly ripe, and experiment proves that, owing 
to the attack of the fungus, there is a loss of weight 
of 25 per cent, in the beans produced, and, at the 
eame time, a very considerable fall in their quality. 
In the old authorities quoted, there is some 
evidence that a disease existed which was very 
destructive to cacao, but the exact nature of which 
was undetermined. It is further reported that it was 
impossible to grow the indigenous varieties and an 
imported strain was introduced which proved to be 
more hardy. 
Prom the results of the attacks recently experienced 
coinciding in some points with the old records it is 
probably to be inferred that the diseases of the 18th. 
century were similar visitations to those of recent 
years. 
There is distinct evidence, however, that the older 
kinds of cacao were not wholly obliterated, and that 
the introduced variety has since intercrossed with 
the original. It does not appear, however, so far 
as present imformation goes, that those strains 
bearing greater relation to the indigenous types, 
are more susceptible to disease than Forastero, for 
the latter appears to snfier equally with others 
from the attack of Phytophthora. 
The evidence in support of the view that the 
older "'blasts" and "blight." attacking the pods a 
century ago, are the same as those of to-day, is 
incomplete and wanting. The probability, however, 
that they are identical is an impression which is 
widespread. 
It would be no little satisfaction to the planter 
if they could be proved identical, as it would show 
the intermittent character of the pe5t, and relieve 
growers of the fear of constant attack. A fact, which 
favours their being identical, is their partial dis- 
appearance during the dry season of 1899 and 1900- 
This may however be due partly to the adoption of 
the measures of prevention which were recommended. 
So far as can be gathered from the evidence at present 
to hand, it would appear that although these fungi 
have only recently been discovered, and their life 
history and destructive character made known, it is 
probable that they have always been present, and, 
if sufficient care is exercised, may be kept within 
due bounds, and will not succeed in seriously damaging 
the crops. The character of the organisms and 
their mode of reproduction teaches that the care- 
less and untidy planter will be the greatest sufferer, 
when a succession of seasons are] experienced favour 
able to their growth , while he who keeps his cultiva- 
tion clean, and in good order may expect to escape 
with minor injuries. 
ANIMAL MANURES. 
A MALODOROUS subject is the dung-hill, withal it is 
one of great and growing importance to the agricul- 
turist and planter, I am afraid the best of us have 
more or loss lamentably failed in grasping its full im- 
port in the economy of Agr.^cuUu£e. As usaal ia 
matters of agriculture the Americans and Canadians 
are greatly to the fore in entering deeply into the 
subject. 
I should suppose there is nothing more distressing 
to read than a lot of laboured satisticsyet some statistics 
are really eloquent and interesting of such a kind I con- 
ceive those in connection with manures of animal origin. 
For example the U. S A. Department of Agriculture 
calculates there are in the States 16,000.000 horses, 
53,000,000 cattle, 45,000,00.» hogs and 45,000,000 sheep 
and if these animals were kept in stalls the year round 
the fertilising properties of the manure produced 
would amount to 2,071,400,000 dollars. This enormous 
total is derived from a consideration of the value of 
nitrogen, phosphoric acid, and potash as commercial 
fertilisers. 
I suggest very seriously to the Indian Agriculturist 
that while we keep the mere phrase manure, we at the 
same time come to a serious consideration of the three 
great ingredients of soil fertility, namely, nitrogen, 
phosphoric acid, and potash ; and look into the matter 
in the same eminently practical business-like way 
the Americans do. A man sells 2,000 pounds of wheat, 
in that 2,000 lbs. of wheat, he has also sold approxi- 
mately R21'8 worth of nitrogen, phosphoric acid, and 
potash ; that much of the fertility of his soil is gone in 
other words that much of his capital account is for the 
time being absolutely depreciated. And consequently 
unless such' an one means to deduct so much from cash 
account clearly he steadily works to nought, in other 
words he comes to a time when the sum total of the 
fertility of his soil is gone, save the indestructable 
residue, which will merely give the amount of crop 
derived from the fertilising properties of rain: and some 
consideration from rotation of crops, particularily 
legumes. This state of things may satisfy the Indian 
ryot, who apparently labours to merely live or rather 
exist, and who would not labour at all if by any 
means he could exist without it: but the European 
planter, the intelligent zemindar, and the agriculturist 
who see some thing in life more than mere existence 
should bestir himself to a much fuller appreciation 
of the commanding importance of animal manures in 
agriculture. Elaborate and conclusive investigation 
into the character of animal manures reveal a whole 
set of facts of great importance to the agriculturist ; 
and many of which are sadly neglected, resulting in 
great loss to the soil and considerable revenue to the 
producer. First, it is important to note that very 
quickly after being voided animal manures commence 
to ferment : horse and sheep manure very rapidly, and 
pig and cow manure more slowly. This ferment ia 
due to minute organisms belonging to two great classes 
those which demand an abundant supply of air and die 
without it, and those which grow without oxygen and 
die when exposed to it : known to science as aerobic 
and anaerobic ferments. In this matter of fermenta- 
tion lay a great deal, indeed all the possibilities of a 
rich fertilising manure, or a blackened mass of com- 
paratively worthless material largely depleted of its 
nitrogen, and phosphoric acid and potash. 
Dr. Voelcker's experiments show that manure pre- 
served in heaps under cover after a year had lost 14 
per cent of its nitrogen, the same exposed 30 per cent, 
and in thin layers exposed 60 per cent at the end o£ 
one year. Elaborate experiments by the Canadian 
Department of Agriculture show that after three 
months about, no advantage accrues from keeping 
manure, on the contrary a steady depreciation seta 
in. It would appear that by this time the micro- 
organisms of the manure and which, by the way are 
largely excreted with the manure have done their 
work of breaking up and simplifying the organic 
portions of the manure quite sufficiently and that after 
this period further decomposition out of the soil ia 
more likely to represent a loss than gain of soluble 
fertilising matter, particularly nitrogen. This apart 
the case is made out most abundantly for a system of 
preparing manure, so that it shall retain all or nearly 
all its fertilising properties, i.e. its nitrogen, potash, 
and phosphoric acid, and this can only be done to tii^ 
