MUCUS. 509 



bronchial membranes in pulmonary consumption. 5. Mixtures 

 of the second, third, and fourth kinds of matter. 6. Pus from 

 vomicae of tubercles. 7. Pus from vomicse of simple inflamma- 

 tion of the lungs without tubercles. 



He made no attempt to ascertain the properties of the mucus 

 contained in these'expectorated matters, but determined the saline 

 contents, and found them to be, 1. Common salt, in the proportion 

 of from 0-15 to 0-25 per cent. ; 2. Phosphate of lime, about 

 0-05 per cent. ; 3. Ammonia united probably with phosphoric 

 acid ; 4. Phosphate of magnesia ? 5. A sulphate ; 6. Carbonate 

 of lime ; 7. Silica ? 8. Oxide of iron. 



Dr Golding Bird has made some interesting experiments on 

 the mucus secreted so abundantly during the first stage of acute 

 bronchitis. When freed from air bubbles it is a transparent co- 

 lourless liquid, rendered reddish brown by sulphuric acid, but 

 the colour disappears on adding water. Nitric acid at first co- 

 agulates it, but dissolves it when heated. Muriatic acid gives it 

 a lilac tint. Ammonia, by the assistance of heat, produces a 

 gelatinous solution, becoming turbid when diluted with water. 

 Acetic acid produces a partial coagulation. Infusion of nut- 

 galls causes a copious precipitate. When evaporated to dryness 

 it leaves a gum-like residue, leaving, when incinerated, a white 

 alkaline carbonate. 



When exposed for a few days to the air it lets fall a cream-co- 

 loured deposit, possessing the characters of coagulated albumen.* 



Dr Babington has shown that the bronchial mucus is always 

 alkaline, f 



4. Mucus of stomach and intestines. In these organs the mu- 

 cus covers the whole internal surface. When an animal is kil- 

 led after a long fast we may scrape a great deal of mucus from 

 the mucous membrane, and obtain it pure by washing it in dis- 

 tilled water. It is a white translucent gelatinous-looking substance, 

 without taste or smell. When dried it loses the property of be- 

 coriiing mucilaginous when water is poured over it ; but if we 

 add a little alkali to the water the gelatinous state is instantly 

 restored. From this we see the use of the small quantity of soda 

 which this mucus always contains in its natural state. 



Acids coagulate it, even acetic acid, and often make it assume 

 the form of a kind of cake. Acids do not dissolve it even at a 



* Phil. Mag., (3d series) xiii. 15. f Guy's Hospital Reports, ii. 539. 



