SCROPHULARINEÆ
=Foxglove= (_Digitalis purpurea_ L.). The Foxglove has been recognized
as poisonous for centuries, and one of its trivial names is Dead Men’s
Bells—a name suggestive of the consequences of taking it. It is the
source of the well-known drug; and cases of human poisoning have been
very common, though by no means always fatal—indeed, Esser says “seldom
resulting in death.” Animals are not known to touch this plant, but it
may possibly be included in rough meadow hay, though only one case, in
which two cows and a horse became ill after eating hay containing dry
foxgloves, has come to notice (_Veterinary Record_, 1906). Cornevin,
however, experimented on animals, and found the following amounts of
fresh leaves capable of causing death in the animals specified:—
Horse 120–140 grammes (4 to 5 oz.)
Ox 160–180 „ (5·5 to 6·5 oz.)
Sheep 25– 30 „ (0·88 to 1 oz.)
Pig 15– 20 „ (0·5 to 0·7 oz.)
The weight of dried leaves would be only one-fourth of these figures.
All parts of the foxglove are poisonous, but especially the seeds, and
the leaves are more active before than after the flowering period.
Cultivated varieties are stated to be less toxic than the wild species.
The effects of poisoning may terminate fatally in a few hours, or if
small quantities are taken regularly the poison may be cumulative and
induce chronic poisoning.
_Toxic Principle._ The foxglove contains several poisonous glucosides,
investigated by Kiliani, Schmiedeberg, Cloette, Bourquelot, Herzig, and
others. The following substances are toxic: _Digitalin_
(C_{35}H_{56}O_{14} or C_{36}H_{58}O_{14}) in the seeds and leaves;
_Digitonin_ (C_{54}H_{92}O_{28} or C_{55}H_{94}O_{28}) in the seeds;
_Digitalein_, only in small quantity; _Digitoxin_ (C_{34}H_{54}O_{11})
in the leaves; and _Digitin_. The toxic property of the foxglove is not
lost on drying or boiling.
_Symptoms._ Digitalis is an active heart poison, and causes nausea,
pressure in the region of the stomach, with diminished pulse, darkening
of the field of vision, dizziness, buzzing in the ears, and usually
dilated pupils.
According to Pammel the symptoms in animals are dullness, lassitude,
loss of appetite, nausea, flatulence, diarrhœa; infrequent, full pulse
(reduced 6–10 beats in the horse); and contracted pupils. In fatal cases
these symptoms are followed by severe colic and tympanites; rapid,
feeble, dicrotic, irregular or intermittent pulse (120–140 in horses),
while the heart may be heard and felt beating wildly and strongly, and a
systolic blowing murmur can frequently be detected. This is due to
mitral or tricuspid regurgitation caused by irregular contraction of the
columnæ carnæ. The pulse is imperceptible because of the failure of the
heart to fill the vessels. The extremities are cold, the eye is
protruding, and salivation occurs. Bloody diarrhœa is very often present
and the urine may be suppressed. The breathing finally becomes difficult
and death ensues within a few hours, or as late as several days.
The following account of the symptoms of poisoning in various animals is
collected by Lander:—
Horses. On the first day sleepiness, swollen eyelids, dilated pupils,
injected conjunctivæ, considerable swelling in submaxillary space;
respiration normal, temperature 103·5° F.; pulse full, between 65 and
75, very intermittent, being occasionally normal; the second heart sound
frequently obliterated. On the next day laboured breathing, head
immensely swollen, tongue greatly enlarged and protruding, pulse 80 and
most erratic, temperature very slightly up, great restlessness.
Respiration became more difficult and stertorous, tongue and buccal
membranes livid, jugular standing out.
A mare experimentally poisoned showed on the _third day_ dullness and
loss of appetite; _fourth day_ nauseated; nose, mouth, and ears cold;
abdomen blown, with colicky pain, and occasional pawing; pupil somewhat
contracted, pulse firm at axilla and heart, but not perceptible at jaw;
at 4.30 p.m. she was down, much pained, and attempting to roll; pulse
82, but unequal; _fifth day_, pulse, imperceptible at jaw, about 120;
respiration 25, and very much laboured: lips retracted and saliva
dripping from the mouth; enormous abdominal tympanites, and much pain;
rapid sinking: died _sixth day_.
Cows. Fed erratically, breathed hard, lay down after feeding. Pulse
almost imperceptible, contracted pupil, and excessive urination.
Pigs. Languid and sleepy: refused to eat or drink, attempting to vomit
and repeatedly passing small quantities of fæces. Urination was scanty
and strained.
In a case of poisoning among horses to which Müller refers the animals
had an exhausted appearance, there was loss of appetite, increasing
thirst, often also colic, and later diarrhœa, urination often in great
quantity, and staggering. Some of the animals died after a few days in
convulsions.
REFERENCES.
4, 16, 73, 76, 79, 81, 161, 170, 187, 190, 203, 204, 205, 213, 229, 252,
257.
=Lousewort= (_Pedicularis_, sp.). Two species of lousewort are involved,
_P. palustris_ L. and _P. sylvatica_ L., and though both are regarded as
poisonous the extent to which they are so is not well known. They have
an unpleasant smell and sharp taste, and are in general refused by all
classes of stock. _P. sylvatica_ may be eaten when young (Cornevin).
Lindley says that both plants are acrid, but are eaten by goats. _P.
palustris_ is regarded by Pott as an acutely poisonous plant, especially
for sheep. A decoction of these plants was formerly used against lice,
and hence the trivial name.
_Toxic Principle._ Very little appears to be known about the poisonous
principle, but, like _Rhinanthus_ and _Melampyrum_, they have been found
to contain the glucoside _Rhinanthin_ (see p. 96).
_Symptoms._ The plants are held to be emetic and purgative; to cause
inflammation of the digestive tract, and to cause anæmia in cattle.
Brugmann stated (_vide_ Cornevin) that if, pressed by hunger, animals
eat _P. palustris_, the first consequence is hæmaturia. Müller also
notes hæmaturia.
REFERENCES.
73, 76, 81, 190, 203, 213.
POLYGONACEÆ.
=Docks= (_Rumex_ sp.). In general it is probable that but little harm is
done by species of _Rumex_, but owing to the fact that Common Sorrel
(_R. Acetosa_ L.) and Sheep’s Sorrel (_R. Acetosella_ L.) contain acid
oxalates they may on occasion prove injurious. Instances have been
recorded in which children have suffered from eating the leaves of the
former species in considerable quantity, and both species have been
accused by veterinary surgeons of poisoning horses and sheep, some sheep
even dying. Pammel states that the Curled Dock (_R. crispus_ L.) induces
nausea, watery brown fæces, copious urination, dry spasmodic cough, and
perspiration; but no record of the death of animals has been found.
In regard to _R. Acetosella_ it is stated that in the _horse_ a
condition may be produced resembling drunkenness, with vacillating gait,
salivation, muscular tremors, dilatation of pupils, relaxation of
sphincters, and a feeble, slow, and intermittent pulse: then convulsive
contraction of lips, retraction of the eyeball, accelerated and
stertorous breathing, extreme dilatation of the nostrils, tetanic
contraction of the muscles of the neck, back, and limbs, abundant
sweating and falling. In bad cases after a period of extreme exhaustion,
these symptoms are repeated, and death occurs in convulsions (Cornevin).
The acid oxalates seem especially harmful to _sheep_, causing loss of
appetite, exhaustion, small and scarcely perceptible pulse, rapid
breathing, and constipation, and in many cases severe diarrhœa,
uncertain gait, and sometimes death (Müller).
The milk of affected cows is with difficulty made into butter (Pott).
REFERENCES.
73, 141, 190, 203, 233.
=Polygonum= sp. Several species of _Polygonum_ are said to have
poisonous properties. The chief among them is Buckwheat (_P.
Fagopyrum_), the grain of which is widely grown as a food for both man
and live stock. This plant, particularly the flowers, has given rise to
a well-known rash in man, cattle, sheep, and pigs, with congestion and
tumefaction—especially of the head and ears. There is also nervous
disturbance, with agitation and hallucination—sheep, for example, may
butt against objects. The affection of the nervous centres may lead to
fatal results, which have followed in cattle, sheep, and pigs. Little is
known of this so-called _Fagopyrism_, but after analytical and
spectroscopical researches on the colouring matter of the tegument Kurt
concluded that it is due to the chlorophyll.
Persicaria (_P. Persicaria_ L.) and Water-pepper (_P. hydropiper_ L.)
are also stated to be harmful, though the former has been considered a
nutritious plant and has been given to horses and cattle as a green
food.
Both species, however, are said to cause a rash, and to contain
injurious narcotic substances. Persicaria is stated by Müller to have
caused inflammation of the bladder and the digestive tract in pigs, and
Water-pepper to have caused hæmaturia; fatal results have followed. Pott
records similar symptoms. In regard to Persicaria it should be noted
that it varies considerably in general form, and may possibly vary also
in acridity. Bentham and Hooker state of _P. hydropiper_ that “the whole
plant is more or less acrid or biting to the taste.”
REFERENCES.
17, 19, 73, 190, 204, 213.
THYMELACEÆ.
=Mezereon= (_Daphne Mezereum_ L.) and =Spurge Laurel= (_D. Laureola_
L.). Both of these species are acrid and poisonous, and cases of the
death of horses due to the spurge laurel are recorded by Lander. In
general, however, animals will not eat the plants, and indeed, in one of
the cases mentioned by Lander the dried leaves were administered for
worms. Should they touch these plants most animals would probably refuse
them on account of their bitter taste. The berries are tempting to
children, and Pratt says “Death has resulted from eating but a few of
these berries (_D. Mezereum_); and Dr. Christison relates a case of a
child, in Edinburgh, who died from eating them, while another is
recorded by Linnæus of a young lady to whom twelve of the berries were
given as a medicine in intermittent fever, and who soon died in
consequence of their corrosive poison. Four berries produced thirst,
sense of heat in the mouth and throat, and also fever, in a man who ate
them; and they are proved to be poisonous to dogs and foxes.” Blyth
states that 30 grammes (1 oz.) of the powdered bark is a lethal dose for
a horse, but smaller doses of the fresh leaves may be deadly (Pammel).
_Toxic Principle._ All parts of these plants are acrid and poisonous,
especially the bark and berries. They contain the bitter, astringent,
and poisonous glucoside _Daphnin_ (C_{30}H_{34}O_{19}—or C_{15}H_{16}0_9
according to Van Rijn), an acrid resin (Mezerein), and a _vesicating
fatty oil_. (Pott remarks that Daphnin is believed to be harmless, but
that Mezerein has poisonous effects.) Drying does not destroy the
poisonous property.
_Symptoms._ The Daphnes are severely purgative, cause burning in the
mouth and throat, and in severe cases have narcotic effects and give
rise to convulsions.
Lander gives the symptoms as intense colic, constipation, followed by
dysentery and copious evacuations of fæces streaked with mucus, blood,
and intestinal epithelium. Drowsiness between the spasms.
According to Müller there is inflammation of the stomach and intestines
(with colic, vomiting, severe diarrhœa, passing of blood), inflammation
of the kidneys (with strangury, bloody urination), and in many cases
nervous symptoms (weakness, giddiness, and convulsions).
In a case observed by Lander, in the horse, there was abdominal pain,
staggering gait, anxious countenance, laboured breathing, pulse 80,
temperature 103·2° F., bowels normal. On the following day there was
excessive purgation, pulse 120, temperature 104·2° F., and death
occurred at mid-day.
REFERENCES.
73, 76, 81, 130, 141, 170, 190, 203, 213, 216, 240.
EUPHORBIACEÆ.
=Spurges= (_Euphorbia_ sp.). Many species of Spurge must be regarded as
acrid, purgative, and poisonous. Live stock are not likely to touch
them, owing to the acrid effect of the milky juice on the mouth.
The Caper Spurge (_E. Lathyris_ L.) contains an acrid, emetic, and
highly purgative milky juice, and the fruits have commonly been employed
by country folk as a purge, and also as a pickle, though they are
dangerous and should not be so used. Pratt records a case in which five
women ate the pickled fruits with boiled mutton, and all suffered severe
pain and burning in the stomach, and showed other symptoms attendant on
irritant poisoning—and though all recovered the illness was severe. Used
in this manner, indeed, they have given rise to serious cases of human
poisoning. Only very young animals are said to eat it, but cattle in the
United States are said to be “quite resistant to its influence, but they
are sometimes overcome.” According to Chesnut goats eat this plant
extensively, and it is said that their milk then possesses all the
venomous properties.
Petty Spurge (_E. Peplus_ L.) is somewhat similar to the Caper Spurge in
poisonous properties, and fatal poisoning has occurred through a boy
eating it.
Sun Spurge (_E. Helioscopia_ L.) is similarly poisonous to the preceding
species. It has caused fatal poisoning to a boy who ate it. In Germany
cows were poisoned through pasturing in stubble in which the plant was
growing, but there were no deaths.
_Toxic Principles._ The milky juice of these spurges contains highly
acrid poisonous substances, which have not been individually and fully
investigated. Drying may reduce the toxicity but does not eliminate it.
_Symptoms._ As regards _E. Lathyris_ Chesnut says that on the skin the
juice causes redness, itching, pimples, and sometimes gangrene. The
seeds when eaten inflame the mouth and stomach, cause vomiting and
intense diarrhœa, and if the illness is serious, nervous disorders,
unconsciousness, collapse, and death.
The _Euphorbias_ have an acrid effect on the mouth, and severe poisoning
may follow their use as aperients—burning mouth, swelling tongue,
stomach pains, cold skin, vertigo, fainting or syncope, and even death
in two or three days (Esser).
Similar symptoms are given by Cornevin, who states that the Euphorbias
have an irritating effect on the mucous membrane, especially at the back
of the mouth. In from three quarters of an hour to two hours after
eating the plant, or even longer, there is painful vomiting, followed by
diarrhœic evacuations, with a lowering of the temperature. If the
quantity ingested has been sufficient there appear also nervous
symptoms, vertigo, delirium, muscular tremors, and respiratory and
circulatory troubles which disappear after abundant sweating if the
poisoning is not fatal. If it is fatal the symptoms of superpurgation
and enteritis predominate, but are accompanied by nervous symptoms and
circulatory disorders.
Müller gives in addition loss of appetite, piteous whining (in goats),
groaning, colic and tympanites; and Pott, bloating, fever, palpitation
of the heart, and loss of consciousness. Cows gave a reddish or
sharp-tasting milk. Milk of affected goats caused diarrhœa human beings.
REFERENCES.
19, 52, 53, 73, 81, 82, 130, 141, 190, 213, 216.
=Dog’s Mercury= (_Mercurialis perennis_ L.) and =Annual Mercury= (_M.
annua_ L.). These two species may be taken together as they have similar
poisonous properties, and closely resemble one another, though the
former is a perennial and the latter an annual. The plants have a
somewhat unpleasant odour, and live stock are not likely to take them
unless pressed for readily available green food. The loss of one cow and
severe illness of four others was recorded by Blackhurst in the
_Veterinary Journal_ in 1896; Güssow mentioned the loss of cows in the
_Farmer and Stock Breeder Yearbook_, 1907; the loss of horses fed on
herbage cut from a hedge and containing _M. perennis_ was recorded in
the _Journal of the Royal Agricultural Society_ in 1898; the loss of
sheep was recorded by Henslow. As regards man, Ray records a case in
which a family of five persons suffered severely from eating _M. annua_
fried with bacon. Fishermen ate it with soup and all were seriously ill
an hour later, with symptoms of irritant narcotic poisoning; two
children died the next day. Cornevin saw _M. annua_ used, after boiling,
as a food for pigs, without ill consequences, in the east of France.
This is believed to be due to the poison being volatile and destroyed by
heat or boiling; hence in hay the plant is harmless, though Pott says
that even in hay stock avoid it.
_Toxic Principle._ The poisonous properties are said to be due to
_Mercurialine, Oil of Euphorbia_, a volatile toxic alkaloid. Esser
states that the stem and leaves of _M. annua_ contain _Trimethylamine_,
which may perhaps be a decomposition product of _Choline_, a poisonous
base.
_Symptoms._ Both plants are emetic and dangerously purgative, causing
irritant and narcotic symptoms. Veterinary observation has shown that
the poison is cumulative, and that it is usually after the weed has
formed part of the food for 7, 8, or 10 days that symptoms first appear.
In the case recorded by Blackhurst (see above) the cows suffered from
inflammation of the digestive tract, with severe purging and loss of
blood. The secretion of milk entirely stopped. One cow died, but three
recovered in about four days. The fifth was not convalescent for three
weeks and then had a permanently curved and injured neck, the muscles
being subsequently found rich in fibrous tissue, and the last three
joints partially anchylosed. Rabbits were tested by feeding two on the
leaves, two on the stems and roots, and two on the ground seeds mixed
with oatmeal; the first two were unaffected, but the other four died in
a few hours, showing drowsiness and suffering, while the post-mortem
showed gastritis.
The digestive and urinary tracts are affected. There is indigestion with
slight bloating, then colic of varying intensity, and at first diarrhœa
which may give place later to constipation; hæmaturia; micturition is
frequent, painful, and the urine is blackish and bloody; dullness,
weakness, loss of appetite and refusal of food; the heart beats very
strongly, the pulse is rapid, and the mucous membrane of the eye is
reddish-yellow in colour. There is no modification of respiration
(Cornevin).
According to Müller, however, the symptoms at _first_ include
constipation and _later_ severe and bloody diarrhœa.
In cattle Pott states that _M. annua_ causes inflammation of the stomach
and intestines, bloody urine, paralysis of bladder, fœtid diarrhœa,
abortion, and bluish coloured milk deficient in fat. Müller states that
there is occasionally blood in the milk. According to Lander there is in
cows excessive bloody purgation, cessation of lactation, temperature
105° F., pulse 90, and increased respiration. The illness is protracted
over several weeks, the animals being comatose after the first symptoms.
REFERENCES.
73, 81, 112, 130, 146, 170, 190, 205, 213, 255.
=Box= (_Buxus sempervirens_ L.). Farm live-stock may occasionally have
the opportunity of browsing on box, or clippings may be thrown to them
with other green herbage from gardens. Care should be taken that
clippings are otherwise disposed of. All parts of the plant are bitter
and have been proved to be poisonous. The bitter taste tends to prevent
animals eating sufficient of the plant to cause serious injury. Pigs
have died a day after eating the leaves. Horses also were killed by
eating 750 grammes (1·6 lb.) of the foliage.
_Toxic Principles._ Fauré found in the bark and leaves of box the toxic
alkaloid _Buxine_, but it was believed that there were other toxic
substances, since analysis showed the leaves to be less rich in Buxine
than the bark, while they are three times as active. Other substances
occurring in box are _Parabuxine_, _Buxinidine_, and _Parabuxinidine_.
_Symptoms._ Small amounts have an emetic and purgative action; with
average amounts, there are, in addition, nervous symptoms, lameness,
muscular tremors, vertigo, then a period of coma. Large amounts cause
death with intense abdominal pains, dysenteric flux, tenesmus,
convulsions, respiratory and circulatory troubles.
Pigs are chiefly affected after eating the leaves, exhibiting great
thirst, uncertain gait and delirium, while death occurs within
twenty-four hours.
Pott gives the general symptoms as sickness, diarrhœa, giddiness,
stupefaction, convulsive movements, and colic.
REFERENCES.
4, 16, 73, 128, 190, 205, 213, 235.
AMENTACEÆ.
=The Oak= (_Quercus_ sp.). Injury to stock from the Oak has been due in
the first place to the leaves, and in the second to the acorns. In
regard to the leaves no injury appears to have been recorded in Britain,
but Cornevin devotes attention only to poisoning by the leaves, which in
special circumstances have caused serious accidents to animals which
have eaten them. In France, cattle taken to the forests for grazing
purposes browse on the young shoots and leaves of the oak, and after
some days there arises a trouble long known as _Mal de Brou_ or _Maladie
des Bois_, which may end fatally, sometimes even in 24 hours (see
_Symptoms_ below). A case was also reported from Nebraska in 1903, ten
head of cattle having apparently died from eating oak leaves, the
trimmings from trees. The stomachs were full of the leaves, and the
intestines had the appearance of being burned in places. There was no
evidence of impaction. When the cut branches were removed no more cattle
were lost.
Serious losses have been caused through the ingestion of acorns by young
cattle not over about two years old, the years 1808, 1870, 1884, and
1900 being especially noteworthy in this respect. Cattle over three
years old have seldom been affected, while sheep and pigs, if not immune
to “acorn poisoning,” are but slightly affected. Müller, however, states
that horses, cattle, sheep, and goats are affected; 9 quarts (10 litres)
taken in four days were sufficient to cause poisoning in the case of a
bullock. It is believed by some observers that half-ripe acorns—_e.g._
acorns which may drop owing to drought—are more injurious than
thoroughly ripened acorns.
Some authorities appear to be of the opinion that “acorn poisoning” is
not actually poisoning, but a serious form of indigestion. If this be so
the symptoms must be regarded as exceedingly severe. There is no doubt
that “acorn poisoning” is not well understood, but a great deal has been
observed and written on the subject, and there is clear evidence that
acorns may reasonably be held to be poisonous. It must be pointed out,
however, that the poisoning does not usually follow on the consumption
of acorns in small quantities, but is commonly due to full meals of
acorns taken in periods when there is a dearth of herbage. By proper
preparation and storage acorns have been converted into a most useful
food for horses, cattle and sheep (_Jour. Bd. Agric._, Sept. 1914 and
Feb. 1916, and Leaflet No. 291 of the Bd. Agric., _The Food Value of
Acorns, Horse-Chestnuts and Beech Mast_). In Germany it has been found
that acorns fed to fowls caused diminished egg-laying, which finally
ceased, while the yolks of eggs laid were discoloured a dirty brown
(_Jour. Bd. Agric._, Dec. 1915, p. 902).
_Toxic Principle._ The facts as to acorn poisoning and oak-leaf
poisoning are not clearly known, and the actual toxic substance is
similarly not certainly known. It is probable, however, that it consists
of _Tannin_, or substances which give rise to Tannin.
_Symptoms._ In relation to _Maladie des Bois_ due to leaves, Cornevin
gives the symptoms as loss of appetite; less (and more difficult)
rumination; constipation, which increases; lying down, animals looking
at their flank as in colic, followed by rising and attempts to urinate,
with passing of rosy-coloured liquid in jets; loss of milk production,
which may drop to nothing; fever, trembling, enfeebled condition.
Three or four days after the commencement of illness rumination is
completely suspended; there is stamping of the feet, colic, retracted
stomach, pulse hard, heart agitated, accelerated respiration, violent
muscular shocks, and frequent urination. The urine is always dark in
colour, but varies from clear red to dark black, nut-brown being usual.
Cases are only serious when a fœtid, frothy, and abundant dysentery
succeeds constipation, in which case there is rapid emaciation and
death.
Usually the course of the illness is not rapid; but occasionally there
is immediate and bloody urination with violent colic and sometimes
intestinal hæmorrhage, death occurring in 24 hours.
In poisoning by _acorns_ there is progressive wasting, entire loss of
appetite, diarrhœa, discharge of an excessive quantity of pale urine,
sore places inside the mouth, discharge from the nostrils, and also from
the eyes, which are always sunken, giving the animal a peculiar haggard
expression. There is no fever; on the contrary, the temperature is
commonly below normal, though in some cases stated to be above normal.
Müller remarks on the severe constipation, followed by dysenteric
diarrhœa, caused by acorns, especially when eaten in the half-ripe
condition, horses, cattle, sheep, and goats being affected.
The experimental poisoning of a young steer and a young sheep by fully
ripe acorns was described in 1871 (_Jour. R.A.S.E._, 1871). In the steer
the symptoms were a semi-conscious condition, weak pulse, pallid
membranes, cold surface of body, torpid bowels, slow breathing,
twitchings of muscles, and a disposition to maintain a recumbent
position. Inflammation was entirely absent. The symptoms increased in
severity day by day; there ensued a copious flow of colourless urine; a
mucopurulent discharge from the eyes and nostrils. No impairment of
health followed the feeding of acorns to the sheep.
Thorburn (_Veterinary Journal_, Feb., 1902) mentions loss of appetite,
grunting, disinclination to move, prostration, icy coldness of
extremities, very rapid emaciation (this sometimes was particularly
noticeable), pulse very small and weak (in some cases almost
imperceptible), temperature high (105° to 107° F.,) and constipation
succeeded by watery diarrhœa.
Brookes and Yeomans described (_Veterinary Journal_, 1912) an instance
in which 30 animals were affected and 9 died. The chief symptoms were a
dull and depressed appearance, entire absence of appetite and
rumination, a weak feeble pulse, subnormal temperature and
disinclination to move. Three cases showed a mucous and blood-tinged
discharge from the nostrils and anus, and these all died, one eight days
after being seen and the other two the day afterwards. Obstinate
stoppage was noticeable in all cases, and the fæces were inky black,
stinking and very thick. Yeomans observed similar symptoms of acute
digestive disturbance; later the eyes had a sunken appearance, diarrhœa
set in, the fæces being dark coloured, offensive and bloodstained. The
temperature was at first normal and later subnormal, and in fatal cases
death took place in from 3 to 7 days.
REFERENCES.
4, 13, 20, 26, 29, 70, 73, 130, 144, 190, 240, 255.
CONIFERÆ.
The only Conifer which commonly causes poisoning of live-stock is the
Yew, but injury might more frequently occur were it not for the fact
that Conifers generally are unpleasant to the taste, and are hence
avoided by stock. Many species, however, contain _Tannin_, _Resins_ and
_Gums_, _Volatile Oils_, and an acrid substance which may cause
inflammation of the digestive and urinary tracts, while Tanret found in
the young shoots of _Picea_ the bitter glucoside _Picein_
(C_{14}H_{18}O_{7}H_{2}O); Kawalier and Thal found the intensely bitter
glucoside _Pinipicrin_ (C_{22}H_{36}O_{11}) in _Pinus sylvestris_,
_Thuja occidentalis_ and _Juniperus Sabina_; and Kubel isolated
_Coniferin_ or _Abietin_ (C_{16}H_{22}O_{8}), a slightly bitter
glucoside found in _Abies excelsa_, _A. pectinata_, _Pinus strobus_,
_Larix europæa_ and other conifers. It is not clear, however, whether
these substances are at all poisonous. It is quite possible that if
eaten in quantity the foliage of some Conifers may induce poisonous
symptoms and even death in the animals concerned. It is noteworthy,
however, that according to Pott the needles of _Picea excelsa_, _Abies
pectinata_, _Larix europæa_, and _Pinus_ sp. are, in the mountainous
districts of Steiermark, Kärnten, and Tyrol, extensively fed to cattle
and sheep, usually as a supplementary food, either fresh or dried and
ground up—chiefly perhaps as an appetiser, and in small quantities as a
dietetic; _Juniperus_ sp. are similarly utilised in some districts. It
is not known to what extent the foliage may be fed without harmful
consequences, but Pott states that large quantities can cause hæmaturia
and similar effects, and hence only small quantities should be used, and
even so may impart a bad flavour to the milk of cows. All green needles
frequently cause digestive troubles.
A case has recently (January, 1916) been reported to the author in which
a Douglas Fir was cut down and a small branch about 4 ft. long was flung
over into a field. Two sheep nipped off the bark and nearly died, but
both vomited and recovered. The farmer reporting this experience recalls
that over 30 years ago, after a gale, a lot of trees were blown down in
a small plantation, and in severe weather the sheep ate the bark to such
an extent that 80 of them aborted, while of the ewes which did not eat
the bark none aborted, so that it would appear that the bark of Scotch
Fir and Spruce was to blame for the loss.
The foliage of the Yew (_see_ below) is well known to be dangerously
poisonous to stock, and has caused many losses.
In regard to _Cupressus_ the only cases of poisoning which have been
traced are recorded in _The Journal of the Board of Agriculture_
(October, 1905). These cases were reported as follows:—
“Two instances have recently come before the Board in which the death of
cattle has been attributed to the poisonous effects of _Cupressus
macrocarpa_ and _C. nootkatensis_. In one case four bullocks died, and
on the internal organs being forwarded by the owner to the Royal
Veterinary College, Professor McFadyean reported that from the inflamed
condition of the fourth stomach and from the description of the symptoms
he had little doubt that the cause of death was irritant poison. Some
pieces of _Cupressus macrocarpa_ were found in their stomachs, and in
default of any other explanation it was suggested that this plant might
have some poisonous properties.
“In another case three heifers are stated to have suffered from irritant
poison; one of them died, but the other two recovered on removal to
another field. The veterinary surgeon in this case also attributed the
death to a Cupressus (_C. nootkatensis_) growing by the side of the
field.
“The Board have no information as to the poisonous properties of these
two species, nor can any record be found of any similar case which would
tend to confirm the suspicion that they are poisonous to cattle.”
REFERENCES.
4, 16, 76, 144, 213, 252.
=Yew= (_Taxus baccata_ L.). As stated above, the Yew is the only British
conifer that is likely to prove seriously poisonous to live stock. It
has unfortunately caused the death of many horses and cattle, while
asses, mules, deer, pigs, rabbits, and pheasants have also been
poisoned. Many cases of fatal human poisoning have also occurred. For
example, the poisoning of a horse, and of cattle, horses, and deer were
mentioned respectively in 1885 and 1893 (_Jour. Roy. Agric. Soc._).
“Through eating the poisonous leaves of a Yew tree, four cross-bred
cattle were found dead in a shrubbery at Elmswell, near Driffield”
(_Daily Mail_, 13th Dec., 1913). Many cases of poisoning and death of
animals due to eating the foliage direct from the trees have been
recorded in the veterinary journals—e.g. the death of 15 cattle in _The
Veterinary News_, 7th Dec., 1912. Tegetmeier recorded the death of
pheasants due to Yew leaves and seeds (_The Field_, 11th Nov., 1893). On
the other hand many cases have been recorded in which fatal results have
not followed the ingestion of the leaves, and it appears that the lower
branches of Yew trees in parks are constantly cropped by cattle without
ill effects. (_Trans. Chem. Soc._, 1902; _Jour. Bd. Agric._, 1903).
The bark, leaves, and seeds are all poisonous, the leaves usually being
the parts eaten. Henslow states that of 32 cases of Yew poisoning 9 were
due to the berries and the remainder to the leaves, while 20 of the 32
cases were fatal. In 1879 R. Modlen published a circumstantial account
of children poisoned at Oxford by the fruits, and demonstrated that the
arillus or scarlet mucilaginous cup surrounding the ripe seed is not
poisonous, but that the seeds are so. Apart from idiosyncrasy of
appetite stock are perhaps more likely to eat the dark green foliage of
the Yew in winter or during scarcity of green fodder than at other
times. The old leaves or shoots are the most poisonous parts.
By experiments with autumn and winter leaves Cornevin found that the
following quantities would be necessary to kill various animals:—
Horse 0·2 lb. per 100 lb. live weight.
Ass and Mule 0·16 lb. „ „
Cow and Sheep 1·0 lb. „ „
Goat 1·2 lb. „ „
Pig 0·3 lb. „ „
Rabbit 2·0 lb. „ „
Other authorities, however, quote much lower quantities as necessary to
kill the horse and ox, and Pott says that in the case of horses 150 to
180 grammes (0·33 to 0·4 lb.) is sufficient to cause death in
one-quarter to one-half an hour, without previous symptoms. Eaten by an
animal on a full stomach a small quantity of Yew may cause little or no
dangerous results.
_Toxic Principle._ The researches of Marmé pointed to the alkaloid
_Taxine_ (C_{37}H_{52}NO_{10}) as the toxic substance. Later
investigations of Thorpe and Stubbs confirmed this view, and it is
generally agreed that this substance is the toxic principle, though
doubts as to its being the only poison have been expressed. Taxine has a
bitter taste, is a heart depressant, and may cause death from
suffocation. The yew also contains a considerable quantity of _Formic
Acid_, and the acrid, irritant volatile _Oil of Yew_.
Thorpe and Stubbs (_Trans. Chem. Soc._, 1902) found in the fresh leaves
of the common Yew from 0·1 to 0·18 per cent. of Taxine. In an
investigation of the Irish Yew (_T. baccata_ var. _fastigiata_) Moss
found Taxine present as follows:—
Leaves from female tree, fresh 0·596 per cent.
Leaves from female tree, fresh 0·623 „
Seeds from fruit of same tree 0·079 „
Another female tree—leaves 0·323 „
Another female tree—seeds 0·082 „
In the leaves of the male common Yew Moss found 0·082 per cent. of
Taxine, or less than one-half the quantity found by Thorpe and Stubbs.
_Symptoms._ The Yew is irritant and narcotic, and the poison is not
cumulative, but on the other hand rapidly effective, so that animals may
die apparently suddenly, no previous symptoms having been observed.
When small quantities only have been taken the closest attention is
necessary to discern the symptoms, which simply consist in a little
excitement with a slight rise in temperature.
With larger (but not fatal) quantities the first symptom, excitement, is
more pronounced and is followed by nausea, and (where possible)
vomiting. There is a pronounced slackening of respiration and
circulation, the pulse being small, slow, and difficult to perceive, and
the movement of the flanks very slow; sensibility is diminished. There
is a fall in temperature, the skin and extremities being cold. The head
is lowered, the eyes are closed and there is decubitus. In some cases
pregnant animals have aborted. In the _horse_ there are muscular tremors
and frequent urination. In _cattle_ and _sheep_ rumination is suspended
and there is more or less pronounced tympanites, with eructation,
nausea, and sometimes vomiting. _Pigs_ bury the head in the litter and
sleep, their sleep being interrupted from time to time by nausea and
groaning; or the animals rise, stagger about, and lie down again.
With fatal quantities the foregoing symptoms may be followed by coma,
with death in two hours or more after the poisoning, but more generally
and usually in horses, asses, and mules (but also in cattle) there is no
period of coma, the excitement is less pronounced and often unobserved,
and death appears very sudden. The animals stop, shake their heads,
respiration is modified, there is falling, and death (sometimes with
convulsions) results from cessation of the heart’s action (Cornevin).
The symptoms given by Müller are roaring, torpidity, stupefaction,
laboured breathing, convulsions and death in from ten minutes to an hour
in the worst cases; or where the course of poisoning is slower, there is
salivation, nausea, vomiting, bloating, retardation of pulse and
respiration, great giddiness and stupefaction, diabetes and hæmaturia.
The rapidity of the poisoning is confirmed by cases noted in the
veterinary journals. Lander shows that the effects often only appear in
cattle when chewing the cud; whilst quietly chewing, they drop as if
shot. In some examples the animal died while eating the plant, or was
found to have fallen and died suddenly and without evidence of a
struggle. The animal in some cases will stop suddenly whilst working,
start blowing and trembling, stagger, fall on its haunches, then on its
side, and die quietly. Death occurs in about five minutes with symptoms
resembling apoplexy. A colt died after 16 or 17 hours; the plant was
taken on a full stomach, but paralysis of the alimentary system with
stoppage of digestion immediately ensued.
In the case of pheasants there was acute inflammation of the small
intestines (Tegetmeier).
REFERENCES.
4, 16, 49, 73, 81, 84, 100, 128, 130, 141, 144, 161,
170, 189, 190, 205, 213, 239, 240, 256.
AROIDEÆ.
=Cuckoo Pint= (_Arum maculatum_ L.). The well-known Cuckoo Pint, or
Lords and Ladies, is to be regarded as highly poisonous, and children
have died from eating the berries. Animals have exceptionally eaten the
plant, but no record of death has been found, as it does not appear to
be taken in sufficient quantity. Cornevin records that pigs have eaten
the roots, and suffered in consequence, though the results were not
fatal. All parts of the plant are poisonous, though the virulence is
lost on drying. The plant is acrid, and emits a disagreeable smell when
bruised. In Gerarde’s _Herball_ the following passage occurs: “The most
pure and white starch is made from the rootes of the Cuckowpint; but
most hurtfull for the hands of the laundresse that hath the handling of
it, for it choppeth, blistereth, and maketh the hands rough and rugged,
and withall smarting.” In Dorset the tuber-like corms have been
macerated in water, dried and powdered, and eaten under the name
Portland Sago or Portland Arrowroot, the poisonous property being
dissipated.
_Toxic Principle._ The Cuckoo Pint does not seem to have received much
attention in this connection, but the poisonous principle is believed to
be a _Saponin_.
_Symptoms._ The juice acts as an irritant when in contact with the
mucous membrane. When a _pig_ has eaten several roots rich in sap, the
mouth and tongue redden and tumefy, there is salivation, and swallowing
is difficult on account of the inflammation at the back of the mouth.
Introduced in small quantity into the digestive tract it acts as an
irritant and purgative, and sometimes causes vomiting. Severe intestinal
pains, excitement, some muscular contraction of the limbs, rocking of
the head, and superpurgation with tenesmus are also symptoms which have
been observed. The intestinal pains continue for some days and the
appetite is small. Cornevin states that animals never take a sufficient
quantity to cause _fatal_ poisoning, but according to Lander, if a
dangerous quantity is taken, convulsions, exhaustion, and death from
shock may possibly follow the foregoing symptoms.
A case in which a _horse_ was poisoned through a wound being washed with
a decoction of arum leaves is cited by Müller. There was much local
swelling, trembling, and rapid breathing, and the heart beat strongly;
the animal died on the third day.
REFERENCES.
73, 81, 130, 141, 170, 190.