It is not by passing the water through the lungs, as the fish does through the branchiæ, that the frog obtains the air held in solution by the water in which he is immersed, the skin is in this case the sole respiratory organ. M. Edwards is satisfied that this mode of respiration is not sufficient to support life, except between certain limits of temperature; a frog immersed in a volume of water which is not changed, continues to live so much the longer as the temperature of this fluid approaches nearer 32°. At this degree frogs are not torpid, as might be supposed, only their motions are slower. As long as the animal immersed in the water remains perfectly alive, which may be known by the vivacity of his motions, it is certain that the respiratory phenomena continue to be performed by him; we see in fact on the membranes in the interstices of the toes, the vessels filled with vermilion blood. When the black colour begins to appear, the animal soon becomes immoveable and insensible. CHAPTER XIII. OF THE INFLUENCE OF THE DEATH OF THE BRAIN OVER THAT OF THE BODY IN GENERAL. From the consideration of what has been said in the preceding chapter, nothing can be more easy than to form an accurate idea of the manner in which the phenomena of general death, commencing by the brain, are concatenated. The series is as follows: 1st, The cerebral action is annihilated. 2dly, There is a sudden cessation of sensation and voluntary motion. 3dly, A simultaneous paralysis of the intercostals and diaphragm. 4thly, An interruption of the mechanical phenomena of respiration and the voice. 5thly, An annihilation of the chemical phenomena of the lungs. 6thly, A passage of black blood into the arteries. 7thly, A slowness of circulation owing to the influx of such blood into the arteries, and the absolute immobility of all the parts, of the intercostals and diaphragm in particular. 8thly, The heart dies and the general circulation ceases. 9thly, The organic life vanishes. 10thly, The animal heat, which is the product of all the functions, disappears, 11thly, The white organs die. Though in this kind of death, as well as in the two preceding kinds, the functions are suddenly annihilated; the parts retain, for a certain time, a number of the properties of life. The organic sensibility and contractility, continue for some time, to be manifest in the muscles of the two lives; and in those of the animal life, the susceptibility of being affected by the galvanic fluid is very great in the muscles of the animal life.