consists, according to Dr. Hayden's analysis, of the earthy phosphates. Also a second and probably similar calculus, 6 by 3 lines. 1870. Dr. H. H. A. Beach.
2703. Over six hundred very small, cream-colored calculi, from the bladder of an ox. Examination by Dr. Bacon. "The largest measures about a line in diameter. Nearly all are regularly spherical, with a smooth surface. They are sufficiently hard to scratch flint glass. Some exhibit indis- tinct concentric layers, but no crystalline structure occurs in any. On chemical analysis, by Dr. Bacon, they are composed of silicic acid chiefly ; with a little animal mat- ter, partly fat ; a little chloride of potassium, and traces of other potash and soda salts. Boiling nitric acid slowly penetrates the calculi, and dissolves out the organic and saline matters, rendering them translucent. After this treatment, they retain the original form and hardness ; and when washed and dried are quite white, and consist of pure amorphous silex. The specimens in the tube-vial exhib- ited have been thus treated. Traces of silex occur in the normal urine of the ox and various other animals, and have also been found in that of man ; but genuine siliceous calculi are of exceedingly rare occurrence." 1857.
Dr. J. B. S. Jackson.
2704. A calculus from the urethra of an ox, that caused reten- tion of urine, and finally rupture of the bladder. Exami- nation by Dr. Bacon : " The calculus weighs 8 grs., and measures 7 lines by 3, being of an irregular shape. It is slightly tuberculated, and is mostly covered by a thin, smooth crust, like a glaze. This has a peculiar semi- metallic or iridescent lustre, and is made up of several very thin laminae. The interior, so far as exposed, is com- posed of thicker layers, of a whitish color.
" Portions from the shining crust, and from layers near the surface, were analyzed. They consist of carbonate, of lime chiefly, with silicic acid, phosphate of lime, and or- ganic matter. The silica forms the principal constituent of some of the laminse, and is not found in others." 1860. Dr. J. H. BlaJce, of N. Auburn, Me.
In the Med. Jour. Vol. LXIII. p. 40, another perfectly
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