Oct. 1, 1902.) THE TROPICAL /VGUrorTLTUPJ.^T. 
PLANT SANITATION. 
The advvntages tjaiued by sanitation, or prj- 
ventiva medicine iu pi-eaerviiig haraaa lifo and 
making it more vigorous are universally recognised 
facta and hafdly needed to be supported by d.ita 
to prove tliem. Two hundred years ago the mortality 
in Lioudou was 80 per l.HOO ; it is now about 2n ; and 
this has been brought about, not by the possession of 
knowlecige of disease and the means of oomtating it, but 
by continually putting suo'i kuowleige into practice. 
The introduction of sanitary methods is compara- 
tively recent. The first Public HeaUh Act was pro- 
mulgated in 1818, though local efforts had been 
made earlier, Sincj then the tendency of such legis- 
lation has been to place the regulation in the hands 
of the local authorities, subject to a general superin. 
tendence by a Government department. Still later 
has oorae the adoption of mea&ures in Britain to piotcct 
animals from disease. Until comparativc^ly recently 
lung disease (contagious pleui-c-pueumonia) and foot- 
and-mouth disease caased large and frequent losses 
of cattle, estimated at nearly 2,00i),00) per annum— 
a loss of perhaps £ 3,000,000 eiich year. Foot-and- 
mouth disease has bjeu almost exterminated. 
Glanders, which was responsible for the loss of largo 
numbers of cavalry horses, is now rare both in Iho 
Army and in private stables. Rabies will no doubt be 
at no distant date recorded iu the category of extinct 
diseases in Britain, if preventive measures are con 
tinuoufly and thoroughly carried ou'. 
Sanitation foe mankind was probably induced to 
some extent by fear ; for animals partly from motives 
of benevolence, but mainly for economic reasons. 
Plant sanitation also must be considered for economic 
reasons. Increase of population necessitates larger 
food supplies. The fight of the farmer in Britain 
and the planter in Gr^a^er Britain must become 
more strenuous as competition, cheapness of trans- 
port, and the opening up of new countries go on. 
Yet while many means of producing larger crops 
and improved varieties have been devised and made 
use of, no means for keeping cultivated plants in 
heal'h, or preventing the spread of epidemics, havo 
been to any extent practised in Bi-itain or encouraged 
by the State. 
That great loss of wealth has been suffered from 
diseases to plants, tigures have b^en frtqnently 
adduced to prove. The potato disease in Ircla-id 
caused immense losses and a disastrous famine. 
The phylloxera ou the vines ol! France reducfd 
the yield of wine by 90 per cent,, and spread to 
and affectpd other Qoutinental vine-growing counirie- . 
Estimates havo been carefully made to show taat 
in An^itralia wheat rust ciuaas a loss of nearly 
£(OU0,;O0 annuUly, In ISS2 the hop-apUis lost to 
Kent and Sussex alone about as much. In ludia 
the annual loss by wheat-rust has been calcu- 
lated at not less than 000,0. lO. In Amsrica 
in 1882 before any steps were taken to mitv^ate 
thpsp evils the Agrioirltural Commissioner estimated 
the enormous sum of from ,£.10,000,000 to £60,Ot)0,0C0 
as the amoant of waste due to insect di;eases 
alone Oevlon suffered to the extent ot probab.y 
ovei '£15,000,000 by the coflte kaf disease, whxcU 
29 
lei to the ruin of the Industry in that island. AH 
these estimates must from the nature of the data 
be only a))proximate ; but even if they err on the 
side of exat'giiration it is plUn that vast losses 
h ive occurred through diseases to cultivated plants. 
Can these losses be reduced or to any extent avoided? 
Tlio answer to this question is found in other landa 
mora than in our country, thou^di in some cases in 
Britain diseases have been treated with success, and 
the cultivator has benefited by his intelligent action. 
Germany and America are in the van in proving 
the v.ilue of knowledge gained and put into practical 
form in the use of sanitary measures for plants. The 
vine industry in France, Italy, Germany, Mtderia and 
other grape-growing cOMUtries was almost ruined by 
the phylloxera, until means were found to minimise 
the attacks, .I'ld varieties of the plants were dis- 
covered in other countries which were immune from 
the ravages of this destructive insect. The vines 
Were still suffering from phylloxera when a mildew or 
blight, due to a fiiogus, began to do serious damage 
to crops. Througli a fortumtte accident — the spiayiug 
of values bv the roadside with blue ttono to prevent 
pilfering of fruit — a fungicide was found for this 
disease, which prevsi.tad the extinction of the vine, 
a .d is still recognised as the most important substance 
for spiayiug in leaf diseases. I:i America, among 
other industries orange growing aad vine culture have 
been relieved from various diseases, and organised 
campaigns have kept the many insect and fungal 
enemies of these important cultivations iu check; 
and in many whoat produoing countries sterilisation 
of reed-corn before sowing has done much to exter- 
minate emut-diseases. 
The large bodies of workers in thesj countries 
are to a great extent helped and encouraged by the 
fact that the people for whom they are woiking 
liave an intelligent knowledge of the miithods and 
results of plant pathology and therapeutics. In 
America - where money's worth is required for money 
— .£000,000 per annum is spi^nt iu supp jrting a large 
staff of experts whose efforts are directed to the 
improvement of agricultural methods, crops and 
slock, the introduction ot new plants, and the pre- 
vention and cure of epidemic diseases. 
It is true that there are cases ot plant disease 
v;iiioh liave not been to any extent lessened or pre- 
veoted by science. But even in the much older 
scioncs of human medicine failures might be men- 
tioned, and yet these still unsolved problems of 
the doctor do not in any degree shake the faith 
of thinking men in the vilue of medicine and sur- 
gery. The plant doctor has frequently to submit 
to the halfhearted carrying out of preventive method?, 
or the refusal to do anything at all to interfere 
vjilh the progress ot a disease. I my -elf, when 
advising tlie proved and practicable remedies for a 
certain disease, have been mot with the remark: 
"Don't you think thai if I got rid "of this disease 
in my trees I should only get some other?" The 
n.iixturo ot ignorance, apathy and fatalism shown 
iu this reply is, to say the least, not enoouraging, 
Futtber, the plant ther,;pjutist does not possess 
one of the chief weapons of the doctor and the 
" vet " against contagious and infectious diseases — 
isolation. Where it possible in the case of a rusted 
wheatfield, a cankered larch plantation, or a blighted 
potato crop to isolate the diseased plants and prevent 
them from con tamiua' iiig their neighbours, the plnut 
doctor and the farmer would have a far easier 
bittle against these diseases. The agriculturist is 
wont to comnlain that the number of diseases by 
which his crops are affeoled is so great ; hut comparing 
any species of cultivated plants with man, the horse, 
the dog, or other domestic auninial, we do not find 
that the disea-es suffered by 'hem are less in num- 
ber than those we deplore in our plants. Plant 
diseases are on tho increase — for very evident reasons. 
In the economy c.f Nature the intermingling of 
species of plants with others differing iu structure, 
habits und iuheteat characters hiLd^rs the progress 
