122 ORGANISED FLUIDS. 



ART. III. MUCUS. 



WE have seen that the blood consists of two parts, the one 

 fluid, the liquor sanguinis, the other solid, the globules ; the 

 same constitution belongs also to mucus as well as to some 

 other of the animal fluids, as for example, pus and milk. 



Mucous globules find their analogue in the white corpuscles 

 of the blood, while the fluid portion of mucus resembles 

 closely the fibrin of the blood, fibrillating or resolving itself 

 into fibres in the same manner as the fibrin. From this fact 

 there can be no doubt but that the transparent or fluid con- 

 stituent of mucus is mainly composed of fibrin. 



It is probable that the fluid portion is the only essential 

 constituent of mucus, and that the globules are connected 

 with it merely in an indirect and secondary manner, notwith- 

 standing that their presence is all but constant. The correct- 

 ness of this view is in some measure sustained by the fact, 

 observed first by M. Donne, that the mucus obtained from 

 the neck of the uterus, in young girls, is invariably free from 

 corpuscles. 



It is with the solid particles of the mucus that we shall 

 be chiefly occupied, for they more properly enter into the 

 domain of the microscope ; the fluid element eludes to a great 

 extent the power of this instrument, and the detection of its 

 properties enters principally into the province of the chemist. 



GENERAL CHARACTERS. 



Healthy mucus, in its fluid state, is a transparent, viscid 

 and jelly like substance, which does not readily become pu- 

 trescent; in its dried condition, it assumes a dark appear- 

 ance, and a horny and semi-opaque texture ; in water it 

 swells up, re-acquiring most of the properties which charac- 

 terised it when recent. It sometimes exhibits an acid, and 

 sometimes an alkaline re-action, according to the exact struc- 

 ture of the mucous membrane by which the mucus is itself 

 secreted. 



