546 Zoological Proceedings of Societies, 



raous serpents, it produces no ill effect on being introduced into 

 the circulation ; a chicken inoculated with it was not affected. 



The author conjectures that this " sweltered venom," as it is 

 correctly termed by our great Dramatist, being distributed over 

 the integuments, serves to defend the Toad from the attacks of 

 carnivorous animals : '* to eat a toad, " has long been held as an 

 opprobrious difficulty ; and the animal is still further protected 

 in this respect by the horny nature of its cutis, which contains 

 much phosphate of lime, &c. As the venom consists in part of an 

 inflammable substance, it is probably excrementitious, and its 

 excretion auxiliary to the action of the lungs in decarbonizing 

 the blood. This view of its use is confirmed by the fact that one 

 of the two branches of the pulmonary artery supplies the skin, its 

 ramifications being most numerous where the follicles of venom 

 are thickest. 



Dr. Davy has found the skin of the Toad to contain por-es of 

 two kinds; the larger, chiefly confined to particular situations, 

 and which, when the skin is held up to the light, appear as iri- 

 descent circles, and the smaller, more numerously and generally 

 distributed, which appear as luminous points of a yellowish co- 

 lour. Externally these pores are covered with cuticle, and 

 some of the larger ones even with rete mucosum ; internally they 

 are lined with delicate cellular tissue. By inflating the skin. Dr. 

 D. ascertained that it was not furnished with spiracula, the exist- 

 ence of which he had been led to suspect by some particular cir- 

 cumstances in the physiology of the animal. 



On the Heart of Animals belonging to the Genus Rana ; by 

 the same author. Dr. Davy has discovered that the heart of 

 the Common Toad, the Bull Frog, and the Common Frog, in- 

 stead of consisting of one auricle and one ventricle, as generally 

 stated, has two auricles, divided by a septum of fibrous substance ; 

 and he has reason to believe that this structure prevails through- 

 out the order of Batraciens, This discovery removes the ano- 

 maly among Reptiles supposed to be presented by these animals, 

 as forming a portion of the link between Mammifera and Fishes, 

 and preserves unbroken the chain of connection between Reptiles 



