54 SECRETION. 



tissue. In addition to this secretion, there is an exhala- 

 tion of watery vapor containing traces of organic matter, 

 coming from the air-cells and the bronchial tubes less than 

 -gij of an inch in diameter, which are not provided with mu- 

 cous glands. This variety of mucus is alkaline and is quite 

 similar to nasal mucus in its appearance and general char- 

 acters. The following is an analysis, by Nasse, of the secre- 

 tion expectorated in the morning by a healthy man : 



Composition of Bronchial and Pulmonary Mucus. 1 



Water 955-520 



Hucosine, with a little albumen 23*754 



Watery extract 8-006 



Alcoholic extract 1*810 



Fat 2-887 



Chloride of sodium 5'825 



Sulphate of soda 0'400 



Carbonate of soda 0'198 



Phosphate of soda 0*080 



Phosphate of lime, with traces of iron 0'974 



Carbonate of lime 0*291 



Silica and sulphate of lime 0'255 



1,000-000 



Mucus secreted l>y the Mucous Membrane of the Ali- 

 mentary Canal. Throughout the alimentary canal, from 

 the mouth to the anus, the lining membrane secretes a cer- 

 tain quantity of mucus, which does not differ very much 

 from the mucus found in other situations. This secretion 

 appears to take place independently of the act of digestion, 

 and the mucus in most parts of the tract is not known to 

 possess any peculiar digestive properties. By ligating all of 

 the salivary ducts, the buccal mucus has been procured. This 

 secretion is produced by the cells covering the general surface 

 of the membrane, and is mixed with the secretion of the iso- 

 lated follicular and racemose glands of the mouth. An ana- 



1 NASSE, Ueber die Bestandtheile des normalen Schleims der Luftwege. Jour- 

 nal fur praktische Chemie, Leipzig, 1843, Bd. xxix., S. 65. 



