450 DISEASES DUE TO VENOMS AND POISONS . 



Scorpions live under stones, the bark of trees, in sand and houses, 

 which latter they leave at dusk. 



They seize their prey with their large six-jointed pedipalpi, hold- 

 ing it close to the mouth with the small three-jointed chelicera;, bring- 

 ing over the tail to sting their victim if necessary, leaving a spine in 

 the body of their prey until the poison compressed from the bilobed 

 gland along the duct to the spinal opening has acted well. 



The venom causes agglutination of red cells leading to thrombosis, 

 haemorrhage due to destruction in the capillar}' walls, coagulation and 

 haemolysis (Jousset de Bellesme). It also contains a neurotoxin. In 

 some respects it simulates cobra venom. 



Treat as for medium cases of snake bite. 



For the pain cocaine can be injected close to the sting. 



Spiders (Aranea). — These grow to a large size in the Tropics. 



All genera appear to be toxic. The poison gland lies at the basal 

 joint of the chelicera, ensheathed in connective tissue. The duct runs 

 forward from the gland to the distal hook-shaped joint, upon the apex 

 of which it opens. 



The effects of the \enom resemble tliose of scorpions, but the 

 general symptoms are often more delayed and mav be of a tetanoid 

 nature, lasting about ten days, as with the bite of Latrodectus mactans. 



With the L. scolis of New Zealand there may be stiffness of the 

 jaw and mouth, difficulty in swallowing and speaking, slow pulse, 

 slow respiration, and death or recovery in about six weeks. It may 

 be confused with tetanus at first and tvphoid later. 



The Theridium lugubre may cause death in a few days. Many 

 .common spiders only cause a local reaction. 



The Maoris will burn down the hut if a single person has been 

 bitten in order to destroy the spider. They believe that its death is 

 absolutely necessary for the recovery of the patient. 



Treat as for scorpion bites. 



Ticks (Ixodia?). — These cause severe effects apart from their being 

 ■ carriers of babesia or spirochceta. 



The skin is pierced by the teeth on the digits of its chelicera?. The 

 digit is moved forwards and turned outwards, enlarging the wound, 

 bringing the hypostome into position, fixing the tick bv means of its 

 curved teeth. The salivary gland at the same time pours a toxic 

 secretion into the wound. 



The Argas persicus, A. reflexus, Ornithodorus moubala cause local 

 pain and swelling. The O. turirala has been known to cause general 

 numbness and swelling, vomiting, diarrho-a, urticaria, profuse sweat- 

 ing, rigors, fever and headache. An ulcer mav form locallv. 



