510 LIQUID PARTS OF ANIMALS. 



boiling temperature ; though they dissolve something. If we 

 decant off the acid, and then treat the mucus with water, an ad- 

 ditional portion is dissolved, these solutions are precipitated by 

 the infusion of nut-galls, but very seldom by prussiate of potash. 

 Very dilute caustic potash or soda readily dissolves the mucus of 

 the intestines. From this solution it is thrown down in great 

 part by the acids. It is dissolved also by very dilute ammonia, 

 and equally precipitated by acids. 



5. Mucus of gall-bladder. This mucus in its natural state is 

 more transparent than that of the nose, but has a yellow colour 

 ob\iously from a mixture of bile. When dried it loses the pro- 

 perty of becoming gelatinous from imbibing water, all the acids 

 coagulate it into a yellow mass, which reddens litmus. Alkalies 

 make it again viscid. Alcohol coagulates it into a horny mass, 

 which cannot again be rendered gelatinous. If we neutralize by 

 an acid the solution of this mucus in potash ley, we obtain a mud- 

 dy thready solution. 



According to Fromherz and Gugert, the solution of the mu- 

 cus of the human gall-bladder in potash ley is not precipitated 

 by muriatic acid, unless we add at the same time a portion of tinc- 

 ture of nut-galls.* 



Tiedemann and Gmelin made several experiments upon the 

 mucus from the gall-bladder of oxen. It was soft and greenish 

 in its natural state, but when dried, it became hard, brittle, and 

 deep grayish-green. It swelled when heated, and burnt with 

 flame, and giving out the smell of burning horn. The ashes con- 

 stituted 8 per cent, of the dried mucus. They consisted chiefly 

 of phosphate of lime with a little carbonate, and contained traces 

 of an alkaline sulphate and chloride. This mucus was partially 

 dissolved by dilute sulphuric and muriatic acid, and the solution 

 was slightly precipitated by tincture of nut-galls, but nitric acid 

 did not seem to dissolve any of it. What remained insoluble in 

 the acids being digested in hot water, was partially dissolved and 

 the solution was precipitated by tincture of nut-galls. It soften- 

 ed and partly dissolved in ammonia.f 



6. Mucus of urinary bladder and urethra. When fresh, it 

 is white and translucent When dried, it assumes a rose-red 

 colour, and is but little softened by water. It is not altered by 

 acids ; ammonia sometimes increases its viscosity, sometimes not. 



" Schweigger's Jour. 1. 70. f Recherches sur la Digestion, i. 43. 



