THE EPIDEMIC PHASE OF CHOLERA IN INDIA.

Cholera, may be studied from

static

a

dynamic

or

point of view. By the static method the disease is contemplated as manifested, and sundry conditions series for comparison in order to are ranged in determine whether the

anything special

or

manifestation coincided with

constant in these conditions.

If

coincidence is observed, a causative relation any is surmised or inferred. By the dynamic method the disease is studied as in process of manifestation, and such

the circumstances

its

accompanying

development

are

in order to ascertain whether any circumstance condition invariably precedes or is associated with its

noted, or

appearance. When any such association is established, The former process a causative influence is postulated. aims at

arriving

at causation

by

a

process

of indirect

exclusion, the latter by direct evidence and positive proof. Each method is legitimate when employed with due care and caution ;

observation and

a

system

of

but of the two the direct method is the

promising and less liable to fallacy. of the static method with which we

more

natural,

The best

example are acquainted, at any rate as concerns India, is the report prepared by Drs. Lewis and Cunningham on the relation of Cholera to certain physical phenomena, published with the thirteenth Annual Report of the Sanitary Commissioner with the Government of India. In for

May

and June last

ful and deta iled

we

criticism,

our

issues

subjected this paper to a careand we endeavoured to demon-

was liable to very serious fallacies the invalidated which conclusions, positive and negative, established by it. We have now before us apparently an able illustration of the other method of cholera in" quiry, the dynamic or direct, in a Report on the Epi-

strate that the method

THE EPIDEMIC PHASE OF CHOLERA IN INDIA.

1878.]

November 1,

demic of cholera of 1875-76 in the Central

Provinces, Townsend, F.C.U., Sanitary

by Surgeon-Major S. C. Commissioner, Central Provinces. with the

dynamic

or

311

unknown or hypothetical element facts the with attacked be success, its existence doubted, may its importance disputed, or its influence canvassed. Other unknown elements may be thrown in or the the

This report deals of cholera as in definite period of time conditions of the

epidemic phase

case altered, and, without changing the facts, aspect may be radically modified by and endeavours to the hypothetical component of the manipulating disclose, with a minuteness of detail and richness This is a perfectly legitimate and indeed theory. seldom of illustration equalled in India, how the It such material. disease arose and spread in the area under report, and necessary mode of handling either amounts to exhibiting the facts in another light, to point out to what agencies and under wha conditions

process of manifestation within a over a definite tract of country,

the

.

the origin and dissemination of the The

epidemic

took

place.

phenomena have been dealt with in another report recently published, in which Surgeon-Major J. L. BRYDEtf, M. D., Statistical Officer attached to the Sanitary Commissioner with the Government of same

narrates the cholera history of 1875 and 1876. Bryden's method also professes to be of the

India, Dr.

dynamic

kind,

direct

or

he does not limit his

but

view to Central India only, but embraces the cholera phenomena, which Dr. Townsend has more elaborately

displayed,

in

disease all

an

account of the manifestation

over

Ceylon during the two years possess the advantage of the

placed

on

record with the

establish the

tion, by two as regards

of the

the continent of Hindustan and in

etiology of writers

in

question.

We thus

phenomena being intention, namely to disease by direct observasame

same

the

of eminence.

The conclusions

causation arrived

at by the authors different, and it is an interesting and not unprofitable study to compare the reports and endeavour to arrive at an opinion as

of these

reports

are

very

which deductions from the same facts are most consonant with reason and probability, and best supported to

by the circumstances of the case. It is necessary to remember, however, that in the absence of positive evidence, a particular conclusion can only be accepted as provisional, and the arguments and illustrations upon constructive and inferenas rather and certain. This is demonstrative eminently the case with cholera. Until we isolate which it rests

tial

than

and

identify

the cholera

poison,

or

define with

precision

disease essentially the conditions upon which must necessarily be depends, all our reasonings the

imperfect can

and

subject

to

doubt and

to establish for

only hope degrees of probability, and

our

dispute.

We

conclusions differ-

highest description of proof that we can attain is moral certainty. As long as an unknown quantity remains, the conclusions arrived at fall short of positive or absolute certainty. The amount of the unknown or imagined, which it is found necessary to employ for the purpose of making our theory square with facts, constitutes a very ent

the

divesting them of the plausibility with which imagination has invested them, or posing them

the

in

a

attitude and trying whether they look more natural and lifelike under a different reflection. It new

is

highly necessary to distinguish the real and ideal in theories, to determine what is timber and what putty, how much is solid truth and how much mere padding. And, after all, the most that can be attained in the present state of science is different degrees of probability. This ought also to be considered, for cholera theories are sometimes criticised as if a positive or mathematically accurate demonstration were possible, whereas until the cholera poison or cause, whatever it is, is isolated and its natural history known, positive and complete evidence is impossible. cholera

On another page will be found Townsend's report, in which dissect his conclusions so

an

careful review of Mr.

a

endeavour

as

to

is made

distinguish

to

the real

hypothetical, and to bring the latter to the bar of probability. In the present article we shall merely sketch and contrast Mr. Townsend's and Dr. Bryden's interpretations of the same phenomena, and point out the amount and kind of padding which each has employed to give roundness and a semblance of solidity Mr. Townsend contends and truth to his theory. that the facts marshalled by him support the positive conclusions that cholera " belongs to the class of infectious epidemics, and that, when it spreads over a tract of country, human intercourse supplies the means by which the infection is conveyed," and that "its seasonal prevalence and its incidence on particular populations are determined by the presence of certain impure matters in the water used by the people, and that drought and rainfall are the chief agents in and the

rendering

the water

impure."

He endeavours at the

time to apply his facts destructively to other theories of cholera causation and development, and contends that the facts and considerations adduced same

in his

report support

(1.) That cholera is in which it occurs.

the

following

never a

product

conclusions

:?

of the soil of the

locality

fair gauge of

(2.) That the spread of cholera over and beyond India is not effected by the means of air-currents that have passed over the Gangefcic delta or other locality in which the disease is considered

same

to be endemic.

the value and truth thereof. The feature renders cholera conclusions peculiarly Without disputing open to destructive criticism.

(3.)

That cholera

belongs

to the class of infective

epidemics.

THE INDIAN MEDICAL GAZETTE.

g-^2 and that human intercourse

supplies

which it

the means by

the infective material of cholera may multiply or increase in water containing sewage or other animal organic matter in a state of decomposition. (5.) That the infective material of cholera, when introduced into the human organism, will not produce the symptoms which constitute the disease, unless a certain state of system suitable for its action in this manner has been previously induced. (6.) That in India this state of system is more commonly induced by the use of water charged with putrescent animal matter,

and that the seasonal prevalence so characteristic of cholera in this country is the result of drought and;rainfall in charging the water supply of the people with impurities of this kind. (7 ) There is reason to believe that the state of system suitable for the malefic action of the cholera infective matter may be induced by inhaling air in a confined space laden with emanations from a sewer or cesspool, or otherwise contaminated with putrescent animal matter ; also that it may be induced by errors of diet; and it is not improbable that it may occasionally arise through faulty action of the excretory and depurating organs, but in this

country these conditions

are not sufficiently common to affect the epidemic," Mr. Townsend succeeds in demonstrating that, when studied with sufficient minuteness, the manifestations of cholera in different localities are successive in point of time, and present, more or less perfectly, the

seasonal course of

aspect

of

an

in

origin

or

detail,

and illustrated

lines.

spread

series of maps.

a

in

an

The

assumption

in

great hypothat

is the agent of elaboration of the its of and conveyance from place to place. This

the human a

by

consists

thetical element

poison

series of centres and

a

This view is worked out in

circles

is

being

matter of

inference,

and must remain

so as

long

as

of the poison are unknown. The probability or likelihood of the inference depends, not on positive demonstration which is in the present state of science impossible, but on the manner and the nature and

qualities

degree in which the known phenomena are rationally explicable by the unknown assumption. But cholera only affects a certain section of the community, and that the smaller, and prevails more severely and widely at

some

seasons than others.

These facts demand asof conditions of another kind governing either

sumptions susceptibility of individuals the poison. Impure water is

the

or

the

development

of

held to be the main condition on which both these postulates depend. Communities or persons are therefore held to be liable to the accident of importation and the modifying influence of

impure water?modifying

predisposition,

and

conveyance of is worked out

respects individual

cultivation, poison. The

maturation

or

whole report these lines, and the phenomena

the on

the

as

expounded on these assumptions. In reading the report?and it is a report which every cholera student should carefully peruse?it is necessary to bear this in mind, and make allowance throughout for the tinge which the arrangement and explication of the subject derive from the hypothetical colouring are

Dr.

Bryden subordinates

known

spreads. (4.) That

interpreted

and

with which the facts

as

stated have been invested.

[November 1,

theory

which he has

the

same

facts to the well

prominently

so

1878.

tinaciously held for the last ten years, we believe, he is the sole expounder

and per-

and of and

which, adherent,

that the cholera poison is a malaria generated in the Gangetic delta and wafted throughout and

namely

India

beyond

by

aerial currents.

The facts upon which he relies are successive manifestations in different areas of the continent, and chronologically coincident appearances in different localities And the

and different years.

padding

consists of the

following hypothetical assumptions:?(1)?a poison ; (2) evolution of the poison from the soil; (3) conveyance of the poison by the air ; (4) distribution of the poison on the surface ; (5) dormancy of the poison ; (6) vivification or vitalization of the poison ; (7) a second and perhaps third dormancy and revivification or re vitalization ; (8) decay and extinction of the poison ; (9) susceptibility or the reverse on the part of localities and (10) persons ; (11) repression ; (12) oscillation, diversion and retrogression ; (13) sanitary defects, and (14) false diagnosis and faulty registration. In short, the only data which Dr. Bryden utilizes are figures in the shape of dates and cholera cases or deaths, the names of places and a souppon of meteorology ; the rest is entirely padding?matter He admits that human agency, of pure imagination. impure water, and other circumstances may aid in the

development and diffusion of an epidemic after it has distributed," so that the main point at issue

been

"

between

Mr. Townsend and him relates to the origin

of the first

epidemic. Now both are agreed that one of the places in which it broke out in 1875 was Nasik,

in the

Bombay Presidency,

where cholera Mr.

appeared

on

Townsend

shows that the wind had blown for months from the Central Provinces towards Bengal; that intermediate places the 22nd of March 1875.

were

free of cholera

Nasik

as a

:

and

points

to the

outbreak at

crucial failure of the wind-borne theory

to account for

a

clear and

prominent

fact in the

early

Dr. Bryden is, however, of this epidemic. He boldly asserts that the equal to the occasion. when the wind was fair in the cholera was distributed that the but conditions favouring of harvest 1874,

history

manifestation did not arise till 1875, the poison lying dormant meanwhile.

This deus

ex

machina is used to

solve two other difficulties in the report, and the paragraph in which the startling proposition is first made is thus of

areas

great motion,

marginally labelled,?" The occupation of Hindustan by an epidemic cholera

but unable to show its presence because distributed when it is incapable of manifestation, a fact." Dr. Bryden's notion of what constitutes a fact must be a very singular one ; and, in putting this marvellous hypothesis forward as a fact he simply places in

November 1,

REVIEW.

1878.]

and surrounds every other a fact with an atmosphere of dubiety. The manner in which he flounders on through dates and figures, laying down with an emphasis of assertion worthy of a stronger case statements which are devoid of a vestige of positive proof, piling himself

beyond criticism,

statement intended to

hypothesis

on

represent

hypothesis, speculation

speculation,

on

garnishing these with tropes and metaphors, writing vaguely of types, standards, homologues, &c.; inventing cholera fans, aerial walls, shadows, beacon fires, and what not, and flavouring the whole with an arrogant air of superiority and undisguised egotism, is one of the most remarkable

of modern times. Is material" to the distances possibility ? We suspect not.

phenomena

the conveyance of cholera

postulated

physical

a

"

particulate or gaseous. If doubt the power of any monsoon to If gaseous, it must obey the law waft it to Kabul. of diffusion, and becoming gradually diluted and

gig

be lost sight of. It is less bulky and makes smaller demands upon credulity in one case than the other; but its existence must not be overlooked, not

and it is proper to reserve a considerable grain of salt for the digestion of conclusions so composed. On the other hand, it is equally absurd to apply to theories founded on incomplete knowledge a critical analysis of too rigid a kind. We cannot, for example, absolutely declare that the undiscovered or unknown is non-existent. This is quite as serious an error as the opposite one of assuming that the creations of imagination are facts. Absolute affirmation or denial in such that

The material must be either

ly

we are

attenuated become

victim to oxygen and

a

sun

heat.

analogy of a vapour capable of precipitation by cold is hardly applicable, and it is the only physical The

analogue

that

we can

"We would not, however,

cite.

be understood to

depreciate the endeavour of cholera epidemics by means of

to

predict

historical parallels and recorded sequences. There can be no question that the features of successive epidemics to the

course

extent resemble each other ; it were very

some

indeed if such which

a

were

resemblance

manifestations of

a

strange

not the case ; and to the extent to can

be traced between the earlier

cholera epidemic and those of pre-

outbreaks, prediction of its future course is No one is better acquainted than Dr. Bryden with the history of cholera in India, and no one better able to apply the experience of the past so as to frame, as far as possible, forecasts and warnings for the future ; but why this method, simple and rational as it ought to be, even though empirical and uncertain, vious

possible.

should be combined with wild

a

loss to conceive.

contrast between the tation of events is

as

we

Space fails us to reports further. different

ludicrous

speculation,

imagery and bombastic asseveration

as

it well

are

quite

at

carry out the The interprecan

be.

Thus

"

Cholera did not spread Nasik." Mr. Townsend contends that it did spread from Nasik. The only reason which we can Dr.

Bryden

asserts

broadly,

from

discover in support of Dr. Bryden's statement is that the disease appeared in Syria on the same day, of the Bombay Presidency about Mr. Townsend works out his thesis in detail, and his interpretation of the phenomena

and in several the

as

same

parts

time !

presented

in his

report,

and

we

have

no

to discredit the substantial accuracy of the certainly to our mind more reasonable and

than the other.

Still,

the

reason

record,

is

probable hypothetical padding must

a case

urged

is

a

is

equally illogical plea of probability

We would not go

bility.

particulate,

we

be

can

far

so

The utmost or

improba-

to affirm absolute-

as

that Dr.

Bryden's postulates are impossible, though strongly inclined to maintain their extreme improbability. The truth of the matter seems to be that where we really know least we pretend to know

very

most,

tolerant

and there is

faith

no

faith in the

so

strong

or

in-

unknown if we can only get ourselves once to believe in it. So it happens that theories regarding cholera are held with peculiar tenacity and criticised with great asperity. There is really no reason, for example, why the evidence in support of its propagation by human agency should be more logically complete and conas

a

unseen

or

vincing than in the case of other diseases presumed It to be spread by similar means such as smallpox. is quite certain that, even with regard to it, difficulties in the interpretation of all its epidemic phenomena on that assumption exist, but very properly allowance is

made for them

on

the

score

of the

imper-

the circumWe may in a future numstances of its propagation. ber take up some of the special points raised in this interesting report. Meantime we would recommend every one interested in cholera to study it carefully, and we fection of

our

would fain

which

we

knowledge regarding

hope

that in

doing

so

all

the considerations

have adduced may aid in arriving at a proper regarding its merits and the value and sub-

judgment stantiality of its

conclusions.