132 ORGANISED FLUIDS. 



ment, should, in one situation, be developed into a shape and 

 a structure so totally dissimilar to that which the same cor- 

 puscles in another position exhibit, the varieties of form and 

 structure of epithelial scales into which the white corpuscles 

 are supposed to be developed being so considerable. 



Mucous globules, then, are to be regarded as young epi- 

 thelial scales, as are also the colourless globules of the blood ; 

 they J)oth have a like structure and a corresponding function 

 to perform, but they have a different origin, thus the mucous 

 globules are developed externally to the lymphatics and blood 

 vessels, while the colourless blood corpuscles are formed within 

 those vessels. 



The further consideration of the ulterior development of 

 mucous corpuscles, or young epithelial cells, will come more 

 appropriately under the head of Epithelium. 



Blood corpuscles not unfrequently occur mixed up with 

 mucous globules, as in the mucus thrown off during par- 

 turition (see Plate XII. fig. L), and as in the rust-coloured 

 expectoration of Pneumonia. 



THE MUCUS OF DIFFERENT ORGANS. 



After the threefold division of mucus which we have 

 given, founded upon the structure of the membranes by 

 which it is secreted, and after the description which has been 

 entered upon of the peculiarities appertaining to the mucus 

 of each of those divisions, it will be unnecessary to enlarge 

 at any length upon the characters presented by the mucus 

 secreted by the membrane which belongs to each particular 

 organ or part ; it will be sufficient just to enumerate the 

 names of the membranes by which each description of mucus 

 is furnished, and to point out any peculiarities which the 

 mucous secretion of any particular organ may present : this 

 having been done, and the distinctive characters of the three 

 forms of mucus having been recalled to mind, we shall then 

 be in a position to assign to the mucus of each locality its 

 principal characteristics. 



