II. 



The Poisonous Secretion of Batrachians. 



'"PHE author of this review would regret if, by drawing attention 

 1 to the toxic properties of the Batrachian integument, he were 

 to revive the former dread of a most interesting and useful 

 group of animals — a feeling which, although still so prevalent, is 

 gradually abating among the educated class. For it must be borne 

 in mind that, although every species, even including the frogs, 

 possesses a greater or lesser amount of poisonous properties for mere 

 protective purposes, no Batrachian has the gift of spontaneously 

 squirting out its poison. No more serious accident than a slight 

 irritation of the mucous membranes can be caused by gently handling 

 even the most formidably endowed members of that group of 

 animals. 



As remarked by Brunton (4), however, animal poisons are at 

 present acquiring a new interest, from the relationship now 

 found to exist between them and the poisons formed by disease 

 germs, and we therefore think some of the readers of this journal will 

 be pleased to find a resume of the present state of our knowledge of 

 Batrachian poisons as a sequel to the short communications which 

 have recently appeared in the correspondence columns of the Lancet 

 (4, 15). The tolerably complete bibhographical index appended to 

 this article will enable those specially interested in the matter to 

 refer to the sources from which it has been compiled. 



The skin of the dorsal surface of all Batrachians is studded with 

 glands and folhcles. In various species, the Toads and Land Sala- 

 manders for instance, some of the larger glands appear as very 

 prominent warts pierced with wide pores, especially a large mass 

 situated on each side of the back of the head behind the eyes (see 

 Fig. I, next page), which has received the misnomer of parotid, 

 a name now generally changed to parotoid gland. These glands 

 secrete, more or less abundantly according to the species, a viscid 

 or milky, more or less and variously odorous fluid, which is 

 exuded when the animal is disturbed, by means of the con- 

 traction of small muscles disposed in the skin around the 

 glands (Leydig, 18). If the larger glands be pressed or subjected 

 to an electric current, the secretion is squirted out with great 

 strength, and sometimes to a considerable distance. Kobert (16) 

 recommends, as the best means of obtaining an abundant supply 

 of toad-poison, the subcutaneous injection of a small dose of chloride 



