CHAPTER III* 



THE GARDEN TOAD {Bufo lentiginosus) 



Technical Note. — Although this description is written for the 

 toad it will fit for the dissection of the frog. It will be found, after 

 casting aside a few ungrounded prejudices, that the toad is the better 

 for class dissection. Toads are best collected abou.t dusk, when they 

 can be picked up in almost any garden in town or in the country. Dur- 

 ing the spring many can be found in the ponds where they are breeding. 

 To kill the toad place it in an air-tight vessel with a piece of cotton or 

 cloth saturated in chloroform or ether. When the toad is dead, wash 

 off the specimen and put in a dissecting-pan for study. Several speci- 

 mens should be placed in a nitric acid solution for a day or so (for 

 directions for preparing, see p. 25) to be used later for the study of the 

 nervous system. Also several specimens should be injected for the 

 better study of the circulatory system. With an injecting mass made 

 as directed in Appendix I, introduce through a small canula info the 

 ventricle of the heart. This will inject the arterial system, and with 

 increased pressure the injecting mass may be forced through the valves 

 of the heart, thus passing into the auricles and throughout the venous 

 system. After injecting use the specimen fresh or after it has been 

 preserved in 4% formalin. 



External structure.— Note that the body of the toad is 

 divided into several principal regions or parts, correspond- 

 ing to those of the human body. Indeed, all through the 

 study of the toad's anatomy a general correspondence of the 

 body-parts and their arrangement with the parts of the 

 human body and their arrangement will be manifest. The 

 toad and ourselves belong to the same great animal branch. 



*If preferred , or the school is not equipped for dissections by pupils, the 

 teacher may substitute demonstrations of already dissected specimens for 

 the dissections by students called for by this and the following chapter. 



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