1 86 



NATURAL SCIENCE. 



of barium ; after a few minutes the animal is so covered with its 

 secretion as to appear as if coated with whitewash. The object of 

 the secretion is to guard Batrachians from the attacks of various 

 enemies. A dog will not often repeat the experiment of seizing a 

 toad ; the signs of pain which it evinces after tlie poisonous fluid has 

 come into contact with its mouth is familiar to most of those who have 

 kept young dogs in the country. That the toad's poison does not 

 protect it against snakes is well known, our common snake, for 

 instance, not feeling any more repulsion for it than for a frog, 

 although it will not eat such Batrachians as Bomhinator and Salamandra. 

 I myself liave witnessed the discomfort of a hungry specimen after 

 having seized a Land Salamander, wliich it very soon let go. But 

 even the Salamander is not proof against one kind of snake at any 

 rate, the common viper. It is also well known to all who have handled 



Fig. l.—Bufo mariniis, a South American Toad with enormously developed parotoid glands. 



freshly-caught Newts, and certain toads, especially Bomhinator, that 

 the secretion of these Batrachians acts as a sternutatory, and 

 causes irritation of the mucous membrane of the nose and con- 

 junctiva ; the effects produced on us by Bovibinator being comparable 

 to the early stages of a cold in the head. German violinists, it is 

 said, when suffering from moist hands, are accustomed to check the 

 perspiration by handling live toads. Many collectors of Batrachians 

 have learned, to their discomfiture, how the introduction of examples 

 of certain species in the bag containing the spoil of their excursion 

 may cause the death of the other prisoners ; for although the poison 

 has^no effect on the skin of individuals of the species which produces 

 it, different species, however closely allied, may poison each other 

 by mere contact. We shall see further on that, when ingurgitated 

 or inoculated, the poison acts even on the individual by which it has 

 been produced. 



