OFFICE OF THE BRAIN. 599 



paribus ; but that their powers of digestion, circu- 

 lation, secretion, nutrition, absorption, muscular mo- 

 tion, and cerebration, depend on the amount of caloric 

 they derive from the atmosphere by respiration* 



The specific office of the brain, spinal marrow, 

 and their nerves, including those of the ganglionic 

 system, is to endow animals with sensation, per- 



* So far is it from being true that the brain is the source of 

 vital energy to the other organs, that when snakes, eels, and other 

 cold blooded animals are decapitated, the trunk remains alive 

 much longer than the head. And Whytt states, that Redi ex- 

 tracted the brain from a tortoise, which afterwards lived from 

 November until the following May, but lost the power of vision 

 and hearing. (Essay on An. Motion, p. 386.) 



It is also evident, from the experiments of Flourens, that in the 

 highest orders of animals, the cerebrum is not essential to respira- 

 tion, which is governed chiefly by the eighth pair of nerves, that 

 arise from the medulla oblongata. For he found that, when the 

 cerebrum of a chicken was removed, it remained in a healthy 

 state for ten months, and even grew fat on being daily crammed 

 with food, that, when thrown into the air, it exerted its wings, 

 as if endeavouring to fly, but lost the power of vision, hearing, 

 tasting, smelling, the feeling of hunger, sexual desire, memory, 

 comparison, and, to a great extent, all its sentient faculties. Yet 

 we are informed by Magendie, that after the cerebrum, cerebel- 

 lum, and all parts of the brain above the medulla oblongata, were 

 removed from a hedgehog, the animal retained, in a low degree, 

 the sense of feeling, smelling, and consciousness, uttered cries 

 when its whiskers were plucked, and made repeated efforts with 

 its fore-feet to get rid of the annoyance. Volkman also found, 

 that, when a decapitated frog was irritated with a hot iron, it 

 leaped forwards, as if conscious of pain. We further learn, from 

 the experiments of Granger and Barren, that, after the brain was 

 removed from a young puppy, it made efforts to suck, thus 

 showing an imperfect power of volition. (Med. Gazette, April 13, 

 1839.) 



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