Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: thing of the kind. On removing the hands and arms from the water, the air-bubbles disappeared, but gradually returned on again immersing those organs. The bubbles were of the size of a pin's head. On wiping them off, they disappeared, but gradually formed again." In opposition to the above observations of Magendie and Girardin, it may be urged that the gas which was developed might probably have arisen from the decomposition of remnants of food in the inclosed portion of intestine, or that the portion of gut becoming distended by peristaltic motion, had imbibed air from the peritoneal cavity, or from the adjacent portions of the intestinal canal; and, similarly, the escape of air from the stomach and urinary bladder, in Smith's case, admits of the same mechanical explanation as has been given in a previous page. Not so, however, the escape of air from the skin : the fact that all bodies, when immersed in water, give off a little entangled air, affords no explanation of the continuous evolution of gas from the skin : neither does the accumulation of air occasionally noticed in the intestinal canal of swine seem to admit either of a mechanical or chemical solution. If we are asked for the particular causes of these developments of gas, I confess I can give no satisfactory reply. No secretion of gases occurs in the human body in a normal condition ; for the development of gas in respiration is a purely physico-chemical proceeding, and is in exact accordance with the laws of displacement and diffusion of gases, as has been recently proved by Valentin and Brunner; and, probably, the same law holds good for the development of gas through the skin. We can only refer to the analogical proceeding in fishes, where we find an actual secretion of gas in the swimming-bladder, and must, for ...