AMPHIBIA 301 



A young dog will suffer discomfort for twenty-four hours after taking 

 a toad in its mouth. Snakes, however, eat toads without any dis- 

 comfort. 



The Indians of Columbia obtain poison from Dendrobates tincto- 

 rium by exposing the frog to fire, and use it for shooting monkeys, 

 as it acts on the central nervous system. Toads do not cause warts, 

 although their skin is poisonous. The Chinese have for thousands 

 of years used a toad-skin preparation called " Senso " as a heart 

 stimulant. It is said to be fifty to one hundred times as powerful 

 as digitalis, to which it is chemically allied. 



Resistance of Amphibia to Poisons. — The toad is not poisoned 

 by dosages of digitalis that prove fatal to the frog. This resistance 

 depends upon a difference in the tissues, as the isolated hearts be- 

 have the same. The frog is tolerant of morphine in quantities fatal 

 to man. 



References on the Amphibia 



Barbour, T. 1926. Reptiles and Amphibians. 



Chamberlain, F. M. 1927. Notes on the Edible Frogs of the U. S. 



Report of the Commissioner, U. S. Fish. Com. 

 DiCKERsoN, Mary C. 1906. The Frog Book. New York. 

 Kirkland, H. a. 1897. The Habits of the American Toad. Hatch 



Expt. Sta. Bull. 46. 

 Miller, N. 1909. The American toad. Am. Nat., vol. 43, pp. 641- 



668 and 730-745. 

 Surface, H. A. 1913. First Report on the Economic Features of the 



Amphibians of Penna. Zool. Bull., Penna. Dept. Agr., Harrisburg, 



May-July. 

 Wright, A. H. 1914. Life Histories of the Anura of Ithaca, N. Y. 



Carnegie Inst. Washington, D. C, Pub. No. 197. 

 Wright, A. H. 1920. Frogs, Their Natural History and Utilization. 



Bur. Fish. Doc. No. 888. 



