NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
90
Scientific Memoirs by
the lethal value of the sample of venom in use being such that 0.006 gramme in
0.5 C. C. of water caused violent general convulsions and death in fowls of
1 kilo. in weight within ten minutes. Slight local muscular action ensued, and
during the rest of that day and the whole of the following one, conspicuous
lameness was present. The animal became very dull, refused all food, and
remained almost constantly lying down for four days. On the fifth day after
the injection it appeared to be livelier, and once more began to feed. Nine days
after the first injection, and when complete recovery appeared to have occurred,
a second dose of 0.01 gramme of dried venom was administered. Conspicuous
dulness was present during the whole of that day and the following one, but
on the latter the animal began to feed again. A week later it received a third
injection of 0.015 gramme, and after this at intervals of four or five days' dura
-
tion, a series of steadily increasing doses was administered, until six weeks after
the beginning of the experiment the dose amounted to 0.055 gramme. The
animal did not bear the treatment nearly so well as the fowl of the previous
experiment did, for a certain amount of dulness and loss of appetite continued
to manifest themselves after each injection, and a continuous and progressive
loss in condition occurred, which had become so marked at the time at which
the injection last alluded to was administered that it appeared to be undesir
-
able to push the treatment further for the time being. An interval of nearly
three months' duration was accordingly allowed to elapse, and an injection of
0.05 gramme, or an amount only a little less than that which had been last
employed, was administered. Conspicuous local irritation ensued, as evinced
by a large amount of swelling around the site of the injection, and the usual
dulness was present for some time, but the animal began to feed again after the
lapse of a few hours.
The principal value of this experiment is to demonstrate that, in the case
of habitual treatment with viperine venom, just as in the case of similar treat
-
ment with colubrine venom, the resultant immunity is not a mere temporary
one, like that arising under the influence of the introduction of extraneous anti
-
venene, but persists over very considerable periods and must, therefore, be owing
to correspondingly persistent reactive manufacture of antivenene by the system.
E.—Experiments dealing with the natural immunity of the Common
Mungoose (Herpestes Mungo ) to the action of Snake-
venoms.
Experiment I.—A mungoose, weighing 1,160 grammes, received an injec
-
tion of 0.0075 gramme of dried cobra-venom, i.e., a minimal lethal dose for fowls
of about one kilo. in weight.
Medical Officers of the Army of India.
91
No symptoms of intoxication followed the treatment.
Four days later the animal was treated with an injection of 0.01 gramme of
the same dried cobra-venom without any result. After an interval of three days
it received an injection of 0.01 gramme of dried daboia-venom in 0.5 C. C. of
water, or a dose equivalent to 2½ minimal lethal doses for fowls of one kilo. in
weight. No symptoms of either acute or chronic intoxication followed.
Experiment II.—A mungoose, weighing 910 grammes, was treated in pre
-
cisely the same fashion as the animal of the previous experiment, and with
exactly the same entire absence of any symptoms of intoxication.
There can be no question whatever that these two individual mungooses
were endowed with a very marked relative immunity to the action of both
cobra and daboia-venoms, as they completely resisted doses which, in the case
of the cobra-venom, amounted to about 14, and in that of the daboia-venom, to
about 2½ minimal lethal doses for fowls of like weight. As, however, both the
animals were mature ones of unknown previous history, it must in the meantime
remain uncertain whether this immunity were of congenital or acquired
nature; whether it had been transmitted to them hereditarily or had arisen
gradually as the result of frequently recurrent inoculations by sub-lethal doses
of venom occurring during the course of conflicts with cobras and daboias.
This is a question which can only be determined by means of experiments of
a nature which have not as yet been conducted, in which the animals employed
have been bred in captivity, or, at all events, have been acquired very young,
and have subsequently been kept under continuous observation under such
circumstances as to preclude the possibility of their coming into contact with
venomous snakes. In the meantime, however, it must remain uncertain
whether the conflicting statements which have been published in respect to the
presence or absence of immunity to snake-venom in various species of
mungooses are to be explained as depending upon the existence of an incon
-
stant and variable acquired exemption, or on the presence of a congenital one
of relative, not absolute degree. If the exemption be an acquired one, it is
clear that it may be entirely absent in certain cases and present in very varying
degree in others, just in proportion to the extent to which opportunities for the
occurrence of antecedent inoculations have been present. If, on the other hand,
it be a congenital one, but of relative, not absolute degree, it is only natural that
it should prove insufficient to equilibrate the effects of excessive doses of venom.
The doses of venom to which such active animals as mungooses are likely to be
exposed during the course of conflicts with snakes must necessarily as a rule be
much smaller than those which they receive when they are forcibly subjected in
a passive state to the bite of venomous snakes, and consequently the mere fact
that death frequently occurs in individuals which have been subjected to such
treatment affords no valid proof that they were absolutely devoid of exemption.
N 2
92
Scientific Memoirs by
This concludes the record of the experiments directly dealing with the
question of the efficacy of antivenene and of cobra-serum as antidotes in cases
of snake-bite and with that of the means of establishing artificial immunity to
the action of snake-venoms, which have been conducted during the course of the
past season. The most important conclusions to be derived from it would
appear to be of the following nature:—
(1) The serum of the blood of animals, which have been artificially im
-
munised to the action of lethal doses of snake-venoms by means of
habitual and cumulative treatment with the latter, unequivocally
possesses antidotal properties, and hence may fairly be denominated
antivenene.
(2) The term antivenene is, however, of generic, not specific value, for
the antidotal material contained in the blood of animals which have
been artificially immunised against colubrine venom is inert against
viperine venom and vice versâ.
(3) The amount of active antidotal material in the blood of artificially-
immunised animals would appear to bear a definite and direct
relation to the amount of venom against which immunity has been
established, the actual quantity of antidote present in the system
in any case being apparently little in excess of that requisite to
equilibrate the toxic action of the amount of venom, under the
influence of which it has been elaborated.
(4) In consequence of this, treatment with crude antivenene is only
adapted to secure recovery in cases where minimal or, at utmost,
slightly supra-minimal lethal doses of venom are opposed by re
-
latively large doses of the serum of highly-immunised animals.
In order to secure recovery after the access of any given dose of
venom to the system, the quantity of antivenene which must be
employed will necessarily vary with the degree of immunity which
has been established in the animal from which it has been derived.
In cases where the degree of immunity has been very high,
relatively limited quantities of antivenene may be capable of
conflicting successfully with small doses of venom; but, as in
order to conflict successfully with any given dose, an amount of
antivenene equivalent to the entire, or almost entire, antivenene
content of the blood of an animal which has been immunised
against a like dose is necessary, in dealing with large doses of
venom the amount of the remedy requisite to secure recovery
must almost inevitably become prohibitive, and treatment with
crude antivenene little better than treatment by transfusion of
blood.
Medical Officers of the Army of India.
93
(5) Treatment with crude antivenin, more especially in combination
with other remedial measures, such as ligature and free incision
and injections of solution of bleaching powder or gold chloride
at and around the site of injury may, therefore, be of some practical
value in dealing with cases in which minimal lethal or slightly
supra-minimal lethal doses of venom are in question, but unless
the really active constituent can be separated from the rest of the
serum, its curative value must remain strictly limited.
(6) The superiority of antivenene over other remedies in dealing with
small doses of venom lies in the fact that its action is not a purely
local one, but one which continues to be exerted subsequent to
absorption into the circulation, so that it is capable of dealing
with venom which has been already absorbed, and may therefore
be an important aid to means which only act locally in reducing
small lethal doses of venom to sublethal ones.
(7) Whilst the serum of the blood of animals which have been artificially
immunised possesses antidotal properties in relation to the venom
in connection with the action of which the immunity has origi-
nated, this is not the case with the serum of the blood of the
snakes which produce the venom, and consequently the natural
immunity of venomous snakes to the action of their own venom
cannot be essentially dependent on any process of auto-inoculation
or, in other words, on the constant and normal presence in their
blood of any material of the nature of the antivenene elaborated
in the bodies of artificially-immunised animals.
(8) The protective effect attending the introduction of antivenene
into the system is a very transitory one, whilst that attending
the habitual introduction of venom is persistent over prolonged
periods, and therefore, whilst in the latter case the protection
would appear to be dependent on persistent, reactive, systemic
manufacture of an antidote, in the former it is seemingly merely
dependent on the introduction of a ready-made antidote, which,
because it is a blood derivative, is capable of remaining for
some time unaltered within the system.
(9) The ingestion of large quantities of cobra-venom, either habitually
or on a single occasion, neither necessarily induces any toxic
effects nor any appreciable protection against the action of the
venom when it enters the circulation.
(10) Mature specimens of the common mungoose certainly may be
characterised by a relatively high immunity against the action of
both colubrine and viperine venoms, but in the meantime it
94
Scientific Memoirs by Medical Officers of the Army of India.
remains uncertain whether the exemption is of hereditary or
acquired character.
In addition to the above experiments dealing with the antidotal properties
of antivenene and the establishment of artificial immunity, another series was
devoted to testing the efficacy of various other reputed remedies, and a third,
and very extensive one, to the investigation of the action of cobra-venom on
the blood. The reputed antidotes which were dealt with consisted of a fluid,
denominated " Viperina," which was sent out to this country by the India
Office for trial, and which is said to have a high reputation in certain parts of
South America ; of a preparation manufactured by a jogi in Western India
and supplied by a Forest Officer of the Bombay Presidency, who had a great
faith in its merits ; and of a local remedy, prepared and supplied by a lady,
named Mrs. Baptiste, residing in the neighbourhood of Calcutta. It appears,
however, to be unnecessary to enter into any detailed record of the results
attending their trial, as they were of exactly the same nature as those which
have been previously recorded in connection with trials of other popular, but
futile, reputed remedies.
In conclusion, I have only once more to record my deep obligations to the
Superintendent of the Zoological Garden, Babu R. B. Sanyal, C.M.Z.S., without
whose willing and intelligent co-operation it would have been a matter of
extreme difficulty to have conducted these investigations satisfactorily.
The 15th July 1896.
On certain diseases of Fungal and Algal Origin affecting
economic plants in India.
BY
BRIGADE-SURGEON-LIEUTENANT-COLONEL D. D. CUNNINGHAM, C.I.E., F.R.S.
The following pages contain an account of what I have hitherto been able
to ascertain regarding the nature of certain common forms of vegetable blights
affecting plants of economic value in India. The materials from which data
were obtained are derived from various sources. Most of those illustra
-
tive of blights affecting potato crops were supplied by district officers and
officials in the Agricultural Department ; the specimens of tea and opium blights
were forwarded to me by Dr. George King, to whom they had primarily been
submitted ; those affecting Pinus and Deodar were supplied by Mr. J. S. Gamble
of the Forest Department ; those on Lucerne and Brinjal by Mr. Mollison,
Superintendent of Government Farms, Bombay ; whilst those illustrating the
blights of the Teak and Terminal Catappa were obtained direct from trees
growing in and around Calcutta.
It must at the outset be confessed that the information contained in the
present paper regarding most of the blights dealt with is very imperfect. With
regard to some of them all that has hitherto been ascertained is that they are of
unequivocally fungal origin, and, in hardly any case, has the life-history of the
parasite been fully ascertained, owing in part, at all events, to the fact that in
very few instances is the disease native to the locality in which it was studied.
It is only, then, as a step towards the acquisition of fuller information, and as a
means of aiding those who may subsequently have the opportunity of fully
working out the subject, that it has been deemed justifiable to publish the data
as they stand. It is never satisfactory to put forth incomplete results, but this
appears to be one of the occasions on which utility ought to be preferred to
inclination and the desire for completeness.
The subject-matter of a paper of this nature might be arranged according
to two distinct methods : the various diseases might be grouped according to
the nature of the parasites which give rise to them, or of the host-plants in which
they occur. The latter method has here been preferred as being of more
practical utility to those who have to deal with the matter from an economic
rather than a purely scientific point of view, and, one similar grounds, the host-
96
Scientific Memoirs by
plants have been arranged, not in the order of botanical taxology, but according
to their relative local agricultural importance.
1. Smut-blight of Rice.
This form of blight, which is dependent on the attacks of a Ustilago which
fructifies in the ovaries of the grains, apparently only prevails abundantly at
comparatively rare intervals, for it produces such very conspicuous effects that it
is very unlikely to escape the most casual observation when present in any
amount, and yet I have only twice had specimens of it submitted to me for
determination,—once several years ago from Chittagong, and again during the
course of the present season from Orissa, where it was supposed to be dependent
on the action of some insect. In all the specimens, moreover, which I have
seen, only one or two grains have been affected in any ear, so that it appears to
be not improbable that the rice-plant is not the sole or even the specially
favourite host, and that it is only under the influence of certain special climatic
conditions which tend to retard growth at a very early stage of development
that it is liable to be affected to any appreciable extent.
The grains which are the subject of attack become very conspicuous from
the great enlargement which the ovary undergoes as the fungal tissue accu
-
mulates within them. They frequently attain dimensions of 0.38" or more, and
as the spores mature and accumulate on the surface, acquire a deep greenish-
brown colour, variegated with orange where the immature mycelia tissue is visible,
(Plate III, Figs. 7-8). The proper ovarian tissues are ultimately completely
destroyed and replaced by a dense web of mycelial filaments which, as they
mature, become converted into masses of spores. The latter are spherical,
coarsely tuberculate, of a greenish-brown colour, and with diameters of about 8
micromillimetres (Plate III, Fig. 9).
The disease, owing to its apparent rarity and limited extension, would seem
to be of comparatively little practical importance, but, were it to make its appear
-
ance anywhere to any serious extent, there can be no question that the best way
to combat it would be to adopt the measures which have been found by
practical experience to be most efficacious in Europe in dealing with blights of
similar nature affecting grain-crops. As infection of the host-plants can occur
only at a very early stage of their development, the occurrence of the blight in
certain individuals of a crop is no source of general infection for their compeers,
as it is in the case of a disease of uredinous origin. It is, no doubt, desirable
to remove and destroy the affected plants ere the fructification of the parasite
has matured, not with any view of preventing further infection of the existent
crop, but in order to protect subsequent ones from liability to infection. As
the masses of spores mature, they are readily disseminated by the wind in the
98
Scientific Memoirs by
and representing the rudiments of the flowers ; and hence, just in proportion to the
rapidity with which the growth of the host primarily occurs, there will be a
diminished likelihood of the blight successfully establishing itself. The fact
that rice is so much primarily cultivated in seed-beds in place of being sown
broadcast in the fields, is thus probably one reason for the very limited extension
of the disease, as under such a system of cultivation the conditions providing for
very rapid initial growth are, as a rule, generally present.
NOTE.—Since the above was written, Professor Oscar Brefeld of Munster has published a paper in the
Botanisches Centralblatt, * showing that this disease is not caused by a member of the Ustilagineae, but by
an Ascomycete, closely related to Claviceps purpurea, which gives rise to ergot in Rye and other Gramineae.
As, however, this discovery does not practically affect the measures for prevention which have been
recommended, and as true Ustilagineous disease frequently prevails amongst the grain crops in this country
to a serious extent the text has been allowed to stand as it originally was.
II.—Blights affecting Potato-crops in India.
a. The common Potato disease of Europe.—This blight, which, as every
-
one is aware, is dependent on the action of Phytophthora infestans, de By
one of the peronosporic group of oomycete fungi, has, of recent years, not
unfrequently appeared in epidemic and destructive form, and, in certain parts of
the country, such as the Khasi hills, in which the cultivation of the potato has
come to a great extent to replace that of indigenous crops, has occasionally
seriously affected the food-supply of the population. The introduction of the
parasite into the country would certainly appear to have taken place only
comparatively recently, and was no doubt effected by means of well-meant but
injudicious importation of large quantities of seed-potatoes from Europe, without
sufficient precaution that they were not derived from infected stock.
The distinctive characters and the life-history of the parasite, so far as
this has as yet been ascertained, are so well known that it is unnecessary to
enter into any details regarding them here. Specimens of the disease have
reached me from the Khasi hills, from the Darjiling district, and from Kumaon,
but none as yet have been obtained from any portion of the plains of India. So
far, then, the disease would appear to prevail epidemically only in hill-areas.
This fact is no doubt to be accounted for by the differences in the external con
-
ditions to which the crops are exposed within the two areas. When cultivated
in the hills they are constantly liable to be exposed to those conditions of atmos
-
pheric humidity which permit of the development of the aerial fructification
of the parasite. (Plate. I, Fig. 12), of the continued vitality of the sporangia, and
of the general diffusion of the zoospores ; whilst in the plains, as cold-season
*'Der Reis-Brand and der Setaria-Brand, die entwicklungsglieder neuer Mutterkornpilze. Von Oscar
Brefeld. Botanisches Centralblatt., Band LX V, 1896.
Medical Officers of the Army of India.
99
crops, they are not exposed to such conditions, and consequently, even if the
disease is actually imported into a locality, its diffusion must necessarily remain
limited. The phenomena are, in fact, precisely parallel to those which we find
occurring in Europe, where general epidemic diffusion of the disease is practically
regulated by the annual variations in atmospheric humidity.
b. Root-blight caused by the invasion of the tissues by a species of Pythiu
m.—This, like the previous disease, is dependent on the presence of an oomy
-
cete fungus, but, unlike it, it occurs in crops cultivated in the plains. Specimens
of it have been obtained from Saharanpur, Gurdaspur and Batala, in the
Gurdaspur district. The fact of its occurring in the plains, and not, like the
Phytophthora disease, being confined to hill-areas, is related to differences in
the habit of the two parasites. In the case of Phytophthora the fungus, al
-
though occurring in the tubers and roots, finds conditions for extensive diffusion
only when it invades the stems and leaves, and having done so encounters
an atmosphere of sufficient humidity to permit of the development of aerial
fructification. In this case the parasite is limited to the subterranean portions
of the host, and here, under the influence of the excessive irrigation to which
the crops are ordinarily subjected in this country, finds all the conditions per
-
mitting of rapid extension. It is not a pure parasite as Phytophthora is, but is
capable of existing saprophytically, and it produces large numbers of oospores, a
form of fructification which, if it occurs at all in Phytophthora infestans is
so rare that it has never yet been met with, and which is capable of lying dormant
during prolonged periods of unfavourable conditions and of subsequently
assuming activity when no longer exposed to them. There are thus various
reasons explaining the extension and persistence of the disease within areas,
such as those of the plains of India, in which Phytophthora is incapable of
producing any appreciable mischief.
All the specimens of the disease were obtained in February and the early
part of March, 1893. In none of them did the foliage or haulms show the faint
-
est trace of the presence of Phytophthora, and the tubers were perfectly
healthy, the only peculiarity being that in some specimens of red-skinned ones
a narrow zone of bright pink was present in an area corresponding with that in
which the fibro-vascular bundles are distributed, an appearance which, as will
subsequently be shown, is sometimes mistaken for that characterising the tubers
in the so-called " Bangle-blight," but which is not dependent on any morbid
textural changes, but merely on the presence of a certain number of cells con
-
taining a red colouring matter, like that present in the cortical tissues.
The disease was certainly associated with, and presumably caused by, the
presence of a species of Pythium the mycelium and fructification of which were
abundantly distributed throughout the cortical and medullary tissues, and, in
minor degree, within the deeper portions of the fibro-vascular bundles of the