508 LIQUID PARTS OF ANIMALS. 



Water, . . . 933.7 



Mucus, . . . 53-3 



Chlorides of potassium and sodium, . 5-6 



Lactate of soda with animal matter, . 3-0 



Soda, . 0-9 

 Albumen and animal matter soluble in water, but in- | 

 soluble in alcohol, with trace of phosphate of soda, / 



1000-0* 



When the mucus of the nose is immersed in water, it imbibes 

 so much as to become transparent and almost invisible ; and 

 when dried on blotting-paper, loses nearly all the moisture 

 which it had imbibed. This may be repeated as often as we 

 please; but the mucus gradually assumes a yellow colour. 

 Though boiled in water it does not lose its mucilaginous nature. 



It dissolves in dilute sulphuric acid. Nitric acid at first coa- 

 gulates it ; but if the digestion be continued the mucus is at last 

 dissolved into a clear yellow liquid. Acetic acid hardens, and 

 does not dissolve it even at a boiling heat. Caustic alkali ren- 

 ders it at first more viscid ; but at last dissolves it into a clear 

 liquid. Tannin coagulates it. 



3. Mucus of the bronchise in a state of health, when expecto- 

 rated, is pretty similar to the mucus of the nose, only its consist- 

 ence is greater and its colour bluish. It possesses, so far as I 

 have tried them, the same characters as the mucus of the nose. 

 The blue colouring matter is probably derived from matter sus- 

 pended in the air drawn into the lungs. It has been remarked 

 to be darker in those who live in great towns than in those who 

 live in the country. 



Dr Pearson made numerous experiments on the matter ex- 

 pectorated from the lungs, which were published in the Philo- 

 sophical Transactions for 1809. He distinguished seven differ- 

 ent kinds of it. 1 . The jelly-like transparent kind of a bluish 

 hue expectorated in health. This is the true mucus of the bron- 

 chiae. 2. The thin mucilage-like transparent matter so copi- 

 ously expectorated in bronchial catarrh. 3. The thick opaque 

 straw-coloured, or white and very tenacious matter coughed up 

 in a great variety of bronchial and pulmonary affections. 4. 

 Puriform matter secreted without any breach of surface of the 



* Annals of Philosophy, ii. 382. 



