155 Thudicum, J. L., On Gall-stones, London, 1863; also Frerichs, op. cit., vol. ii. p. 503.
156 Cyr, Jules, Traité de l'Affection calculeuse du Foie, Paris, 1884, p. 11 et seq.
The body consists of cholesterin, nacreous or darkened by pigment, deposited in radiating lines or in concentric layers, or in both together. Pigment may be intimately incorporated with the cholesterin or deposited between the layers of this substance, pure or nearly pure, forming an alternating arrangement.
The crust or rind usually is smooth, unctuous to the touch, firm, but when broken with the finger-nail readily crumbles. When composed of lime salts, or when the cholesterin is mixed with varying proportions of these salts and of pigment, the surface is still smooth, but thicker, firmer, and darker in color. The rind may not be smooth, but studded with wart-like projections, or it may consist of several layers of earthy matter separated by pigment. These layers may be very friable, and readily crumble and fall off. In some instances the crust, several lines in thickness, is the body of the calculus, and the cavity contains only a light honeycomb of mucus and pigment.
The specific gravity of gall-stones composed of crystallized cholesterin is nearly that of water. Air-dried calculi will float on water, but the recent ones, full of moisture, sink. The relation of the weight of the calculus to that of the bile is more important. As the specific gravity of bile ranges from 1020 to 1026, it is obvious that on this fluid air-dried calculi will float, but, holding in the recent state much water, ordinary gall-stones will sink. Those containing much mineral matter will have a correspondingly high specific gravity—much higher than bile.
ORIGIN AND FORMATION OF HEPATIC CALCULI.—Certain conditions are necessary to the formation of these bodies on the part of the bile and on the part of the gall-bladder and ducts. Constituted for the most part of cholesterin, which exists in such small quantity in normal bile, there must be some change in the composition of this fluid to increase the quantity or to diminish the solubility of that constituent. It will conduce to a better understanding of the subject to premise the composition of the bile:
| Bile contains, in 1000 parts, | |
| Water | 860 |
| Solids | 140 |
| The solids of bile are, | |
| Glycocholate and Taurocholate of soda | 90.8 |
| Fat | 9.2 |
| Cholesterin | 2.6 |
| Mucus | 1.4 |
| Pigment and extractive | 28.0 |
| Salts | 8.0 |
| 140.0 |
Normal bile is neutral or slightly alkaline in reaction. If the reaction become acid from any cause, the constituent cholesterin is precipitated; and this occurs the more readily the larger the proportion of this substance held in solution. Cholesterin is an excrementitious material found in the blood and excreted by the liver. It represents in part, probably, the waste of nervous matter, but more certainly of the fatty tissues in general. Conditions of the system in which the metamorphosis of the fatty elements occurs more freely—as obesity, advancing life, etc.—are accompanied by an increased production and excretion of cholesterin.