VENOMS IN THE ANIMAL SERIES 321 



loses its properties. By the ordinary methods of immunisation 

 it is possible to obtain a very active antilysin. 



There is, therefore, a very close analogy between the venoms 

 of toads and salamanders. These highly complex substances are 

 composed of mixtures of poisons, some of vyhich are in all 

 respects analogous to the vegetable alkaloids, while others are 

 closely related to the microbic toxins and snake-venoms. 



In the spawning season the cutaneous glands of the male toad 

 are gorged with venom, while those of the female are empty. 

 Phisalix ^ has shown that at this period the venom of the female 

 is accumulated in the eggs, which, if extracted from the abdomen 

 at the moment of oviposition and dried in vc(,cuo, give off in 

 chloroform a product that has all the toxic properties of cutaneous 

 venom (bufotalin and bufotenin). No trace of this poison is to be 

 found in the tadpoles. 



B.— Lizards. 



The Order Lacbrtilia includes only a single venomous species, 

 which belongs to the family Lacertidee, and is known as the 

 Heloderm (Heloderma horridum, fig. 124). It is a kind of large 

 lizard, with the head and body covered with small yellow tubercles 

 on a chestnut-brown ground. It sometimes exceeds a metre in 

 length, and its habitat is confined to the warm belt extending 

 from the western slope of the Cordilleras of the Andes to the 

 Pacific. It is met with especially in the vicinity of Tehuantepec, 

 where it inspires the natives with very great dread. It is a slow- 

 moving animal, and lives in dry places on the edges of woods. 

 Its body exhales a strong, nauseous odour ; when it is irritated, 

 there escapes from its jaws a whitish, sticky slime, secreted by 

 its highly developed salivary glands. Its food consists of small 

 animals. Its bite is popularly supposed to be extremely noxious, 

 but, as a rule, the wound, though painful at first, heals rapidly. 



' Comptes rendus de I'Academie des Sciences, December 14, 1903. 

 21 



