164 Miscellanies. 



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" none is so fierce that dare stir him up." But all vitality, all mus- 

 cular energy, depends on the act and effects of respiration ; and how 

 are these hahits of the crocodile to be reconciled with this law? On 

 land, when breathing the atmosphere at full, he is sluggish and fear- 

 ful ; it is only when immersed in water, and when respiration is Hable 

 to be impeded, that he acquires strength, activity, and courage. 

 There is here an exception to the law, but it is only in appearance ; 

 and it is curious to remark how simply nature in this case enlarges the 

 respiratory organ and function, and gives the aquatic creature its cor- 

 responding power, without deviating in any thing from the one model 

 of organization. By means of two canals which take their origin in the 

 cloacum, and which open into the cavity of the peritoneum, water is 

 conveyed within the abdomen to act upon the blood in its vessels ; 

 and through the abdominal vessels thus called upon to aid the lungs in 

 oxygenating the blood, the additional vigor to the muscular system 

 is imparted. The crocodile has an abdominal sternum independent- 

 ly of its pectoral sternum : each sternum and its muscles regulate the 

 effects of their proper and respective respiration. When the animal 

 is on land, it is the thorax and its sternum which are only in action ; 

 when in the water, the abdomen and its sternal apparatus are like- 

 wise called into play. Isidore Geoffrey Saint-Hilaire and Joseph 

 Martin were the discoverers of the canals which open into the peri- 

 toneum ; a discovery of great interest, as previously to it the habits 

 of the crocodile were inexplicable. — Mag. of Nat. Hist. Sept. 1830. 



6. Are the songs of birds innate or acquired'? — This question has 

 occasioned some controversy among the contributors to Loudon's val- 

 uable Magazine of Natural History. One writer (R. Sweet, Pomona 

 Place) maintains that blackbirds or thrushes, brought up in a city^ 

 will have no variety in their notes, and will only imitate the tones of 

 people who whistle to them, or the discordant noises of tlie streets. 

 A nightingale, caught when young, and which he had kept for three 

 years, only sang two or three notes. It was turned out in the sum- 

 mer, migrated in autumn with other birds, but returned in the spring, 

 and was recognized by its imperfect notes. Another bird (Saxicola 

 Rubetra, or Whinchat) bred from the nest, turned out to be a very 

 fine singing bird, but its notes were all acquired by mocking other 

 birds, and had scarcely any thing in them of the natural song of the 

 species. Other birds, which had acquired their own wild notes when 

 taken, learned also to imitate die cage birds around them. Even in 



