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Full text of "Medical Jurisprudence And Toxicology"

SNAKES                                                         605

pain, irritation, redness, swelling and inflammation at the seat of injection
of the venom. These are~followed after an interval varying from fifteen
minutes to one to two hours by giddiness^Jefliargy, muscular weakness and
a feeling of intoxication. Nausea an^Tvomiting are sometimes the early
symptoms. Weakness of the~muscles increases, and develops intopcygl^sis
of the lower limbs, so that the victim staggers or falls if he attempts toittml
or walk and lies down. Paralysis then spreads to the trunk, and affects the
head which droops. The muscles of "the lips, tongue and throat become
gradually paralysed. As a result speech and swallowing become difficult, f
and saliva collects in the mouth. The^ victim is often seen trying to
remove the viscid saliva from his mouth witEThis fingers. Breathing becomes
slow and laboured, until it stops altogether, the heart continuing to beat for
some minutes. Consciousness is retained till the end. In a bite from a krait
violent abdominal Jssifis~ahd convulsions may precede death.

If recovery occurs, the skin and subjacent cellular tissues surrounding
the bitten area die and lead to the formation of a slough. Later, the slough
separates and leaves a big ulcer.

In the case of a bite from a viper, such as a daboia or echis, the local
signs are a good deal of pain, swelling, discoloration and ecchymosis in the
immediate neighbourhood of the seat of the bite and oozing of a bloody
serum from the apertures caused by the bite. Within a few seconds to fifteen
minutes after the bite nausea, vomiting and the signs of collapse supervene
with the cold, clammy skin, a small thready, imperceptible pulse, and dilated
pupils which are insensible to light. These are followed by complete un-
consciousness. If the patient recovers from these effects, haemorrhages occur
from the mucous membranes of the rectum and other orifices of the body.
Extensive local suppuration, sloughing and gangrene, and malignant oedema
or tetanus may supervene or death may occur from septicaemia.

In some cases of snake bite death occurs from shock due to fright before
the poisonous symptoms commence.

Snake venom, whether colubrine or viperine, has a haemolytic action on
the blood, and reduces the power of its coagulability with the result that a
bloody serum continues to ooze out from the wound for many hours. This
oozing is more pronounced in viperine poisoning than in colubrine poisoning.
The absence of the oozing of the bloody serum shows that the venom has
not been injected into the wound.

Fatal Dose.—Fifteen to twenty milligrammes of the dried cobra venom
and 40 milligrammes of the daboia venom. The amount of the dried venom
yielded by a cobra in one bite is 200 to 370 milligrammes, and 150 to 250
milligrammes by a large daboia. From experiments conducted by Knowles 8
it was found that the amount of cobra venom injected at a successful bite
averaged from 172 to 211 milligrammes, while in the case of one cobra the
amount of the venom injected at a single bite was 587 milligrammes or about
40 times the minimum lethal dose for man,

Fatal Period.—Death occurs from twenty minutes to thirty hours after a
bite from a colubrine snake and in two to four days after a bite from a vipe-
rine snake, but it may occur instantaneously or within a few minutes if the
venom is injected into a vein* A case is recorded where the bite of a king
cobra caused death in convulsions in three-quarters of an hour,0

Treatment.—Apply at oixce a ligature with a thick India rubber band,
a piece of cord or a strip of cloth at some distance above the site of the
wound if the bite is on an extremity, The ligature should be tight enough

8.    Ind. Med. Gaz., Jan. 1922, p. 23.

9.    Tropical Diseases Bulletin,, May 1930, p. 360.