276 VENOMS 



Kobert^ has made an experimental study of the venom of 

 species of Latrodectus and Epeira. That of Latrodectus erehus 

 (the Karakurte of South Eussia) is particularly toxic. 



If a dry extract of these spiders be prepared and injected into 

 the veins of dogs or cats, it is found that a few milligrammes 

 per kilogramme are sufficient to cause death, with phenomena of 

 dyspnoea, convulsions, and progressive paralysis of respiration 

 and the heart. Eabbits, rats, birds, frogs, and leeches are also 

 sensitive to this poison, though the hedgehog is almost refractory, 

 The young spiders, and even the eggs, are more toxic than the 

 adults. 



Spider-venom is destroyed by heating for forty minutes at 

 + 70" C, and is precipitated by alcohol. When absorbed by 

 ingestion it has no effect : it is heemolytic and coagulates blood. 



The study of arachnolysin by Ehrlich's methods has been 

 undertaken afresh by Hans Sachs," who has shown that rat's and 

 rabbit's blood are most rapidly dissolved. Twenty-eight milli- 

 grammes of extract of Epeira are capable of completely dissolving 

 0-05 c.c. of blood. 



By immunising guinea-pigs and rabbits, Sachs succeeded in 

 obtaining a strongly antitoxic serum, which entirely prevents the 

 haemolysis of the sensitive red corpuscles. 



(b) Scorpionidea (Scorpions). 



The poison-apparatus of the scorpion is constituted by the last 

 abdominal segment {telson), which is swollen and globular, and 

 terminated by a hard, carved spine, with a very sharp point, near 

 which can be distinguished, under the lens, two small oval orifices 

 by which the poison is enabled to escape (fig. 97). 



The poison-glands are two in number, symmetrically placed in 



' "Beitrage zur Kenntniss der Giftspinnen." Stuttgart, 1901. 



^" Zur Kenntniss des Kreuzspinnengiftes," Hofin. Beitrage, ii., p. 12.5, 1902. 



