xxvi 



(cinchona) have also their fixed limits, 

 which I have marked in the botanical chart 

 belonging to this essay. 



V. Collection of observations on zoology 

 and comparative anatomy *. I have com- 

 prised in this work the history of the 

 condor ; experiments on the electrical ac- 

 tion of the gymnotus •f ; a treatise on the 

 larynx of the crocodiles, the quadrumani, 

 and birds of the tropics ; the description 

 of several new species of reptiles, fishes, 

 birds, monkeys, and other mammalia but 

 little known. A distinguished man of sci- 

 ence, whose constant friendship has been 

 highly honorable and advantageous to me 

 during a great number of years, Mr. Cu- 

 vier, has enriched the collection with a 

 very extensive treatise on the axolotl of 

 the lake of Mexico, and on the genera of 



* Zoolog. Obs. two vols, in 4to. The first of these 

 volumes is published with thirty plates, most of which 

 are colored. The second volume is far advanced. 



f These experiments are connected with those I 

 published previous to my departure to America, in 

 the second volume of my essay on the irritability of 

 the nervous and muscular fibre, and on the chemical 

 action which keeps up the life of animals and plants. 

 1796. 



