93 THE SECRETIONS: 



pus is rich in albumen, and contains only a very small quantity 

 of dissolved mucin. Hence, if it were proved that normal mucus 

 never contains albumen, we might conclude that all mucus 

 which gave indications of the presence of that substance was 

 purulent. We should then also arrive at the conclusion that 

 most persons, on the slightest irritation of the mucous mem- 

 brane, secrete purulent mucus. In this manner we should have 

 to agree with Vogel that normal mucus contains only epithe- 

 lium, and that any secretion of mucus- corpuscles indicates an 

 admixture of pus. 



To the physician the detection of traces of pus in mucus is 

 a point of little importance ; it is of much more consequence to 

 be able to decide from the sputa whether suppuration of the 

 parenchyma of the lungs or of other tissues has actually com- 

 menced. The point is one of very great difficulty, in conse- 

 quence, as has been previously observed, of the imperceptible 

 changes that mucus undergoes in its transition from the normal 

 secretion into pus. 



My own observations, as well as those of others, lead me to 

 concur in the view that Henle 1 has developed in his essay on 

 the Secretion of Pus and Mucus, in which he distinctly and in- 

 geniously points out the analogous phenomena between mucous 

 membranes and the external skin. The mucous membranes are 

 covered with several layers of epithelium, and in the ordinary 

 course of secretion, the more recent and inferior layer of cells 

 projects against the superior and older cells which constitute the 

 existing epithelium. The inferior cells themselves gradually 

 become epithelium, and, in their turn, are thrust out and 

 supplanted by still deeper cells. As the fluid portion of the 

 mucus is secreted at the same time, it evidently cannot be re- 

 garded as the cytoblastema of these cells, but must be looked 

 upon as effete, and no longer essential to the formation of mu- 

 cus-corpuscles; the albumen for their nutrition having been ex- 

 tracted from it during the progress of their development towards 

 actual epithelium, and only mucin (the product of their meta- 

 morphosis) left in its stead. 



As the secretion is increased by irritation of the mucous mem- 

 brane, it follows either that such epithelium as is thrown off in 

 the normal state is then not formed at all, or else that it is 



1 Hufeland's Journal, May 1836. 



