1, Female, twice natural size; 1_a_, its eyes, greatly enlarged.] Another dangerous spider is the _Katipo_ (_Latrodectus scelio_), of New Zealand. This creature is confined to the sea-shore, and the natives are often bitten when collecting shell-fish or sea-weed. The Maoris are so much afraid of the bite of the _Katipo_ that, when one of them has been bitten in his hut, and the animal cannot be found, they do not hesitate to burn the dwelling to the ground. Moreover, they are convinced that the death of the spider is absolutely necessary for the recovery of the patient.[112] Kobert[113] has made an experimental study of the venom of species of _Latrodectus_ and _Epeira_. That of _Latrodectus erebus_ (the _Karakurte_ of South Russia) 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 dyspnœa, convulsions, and progressive paralysis of respiration and the heart. Rabbits, 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 hæmolytic and coagulates blood. The study of _arachnolysin_ by Ehrlich’s methods has been undertaken afresh by Hans Sachs,[114] who has shown that rat’s and rabbit’s blood are most rapidly dissolved. Twenty-eight milligrammes 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 hæmolysis 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, curved 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 cavities, each of which is completely filled by the gland. They are separated from each other by a muscular septum formed of striated fibres inserted in the chitinous skeleton; by the contraction of this septum the animal is enabled to eject its venom. [Illustration: FIG. 97.--_Scorpio occitanus._ (After Joyeux-Laffuie.) 1, Scorpion seizing a spider, and piercing it with its sting (natural size); 2, extremity of the abdomen (telson) enlarged, showing the poison-apparatus; 3, poison-apparatus detached from the abdomen, showing an isolated poison-gland.]