32 INTRODUCTION. 



as to the nature of the secretion ; some regarded it as 

 an acid, others as an alkaloid. Phisalix, in 1890, 

 claimed to have solved the question by reconciling 

 both views, he having found toads to be simultaneously 

 possessed of two different kinds of glands, different 

 both anatomically and physiologically. These are 

 mucous or slime glands spread over the greater part 

 of the body, the exudation of which is controlled by 

 the animal; and specific glands (the parotoids and the 

 larger dorsal glands), the product of which can only 

 be squirted out by foreign agency. The secretion of 

 the former glands is an alkaloid, and acts as a 

 narcotic ; that of the latter is an acid, and acts as a 

 convulsive. The anatomical differences of the two 

 kinds of glands have since been worked out by Paul 

 Schultz, who, however, regards the product of the 

 slime glands as innocuous. 



Phisalix and Bertrand's recent investigations have 

 shown the active principle of toad-poison, the so-called 

 phrynin,to be also present in certain quantities in the 

 blood of these Batrachians. 



Even the frogs of the genus Rana, so sensitive to the 

 poison of other Batrachians, are not free from toxic 

 properties. A goldfinch inoculated by Paul Bert with 

 the dermal secretion of Rana esculenta died in one 

 minute ; a frog of the same species in one hour and a 

 quarter. 



The secretion of Alytes, Pelodytes, and Pel abates 

 smells like garlic, so strongly in the last that I have 

 observed the odour to remain for hours in a room 

 after I had purposely irritated a few specimens. 

 That of Bufo ealamita smells like boiled india- 

 rubber, like ignited gunpowder, or a Dutch clay pipe 

 smoked for the first time, according to Rosel's com- 

 parison ; whilst that of its near ally, Bufo viriclis, 

 always reminds me of a linseed poultice. 



A chemical comparative study of the dermal secre- 

 tion in the various types of European tailless Batra- 

 chians is still a desideratum. 



