o8 MUCOUS SOPTENINa. 



In this connexion the development of mucous tissue takes a 

 leading place. Following Virchow, we apply the name to a con- 

 nective tissue "whose matrix has undergone mucous softening, and 

 whose corpuscular elements, owing to this softening or " swell- 

 ing by imbibition," are pushed asunder to some extent, with- 

 out necessarily undergoing any alteration in their form. Mucous 

 tissue is much more widely distributed in the embryo at an early 

 stage of its development than in the adult organism. The whole 

 of the subcutaneous areolar tissue is primarily a subcutaneous 

 mucous tissue. At birth, apart from the AVhartonian jelly of the 

 umbilical cord, we find only one portion of residual mucous 

 tissucj but that an important one, in the vitreous body of the 

 eye ; this retains a singular stability of composition to the end 

 of life. 



In the pathological field the production of mucous tissue is 

 far more manifold. We have tumours {Myxomata) which are 

 wholly made up of mucous tissue ; and others, such as enchon- 

 dromata, lipomata, and sarcomata, which undergo a secondary 

 conversion into mucous tissue. Mucous tissue is a constant ele- 

 ment in syphilitic gummata, and it is occasionally found in 

 fungoid granulations and other growths of an inflammatory 

 origin. We defer a detailed consideration of these various 

 modes of its production till we begin the study of inflammation 

 and tumours. 



Of the remaining morphological effects due to the incapacity 

 of mucus for reabsorption, we need allude in this place only to 

 its cystic and cystoid deposits ; the former determined by occlusion 

 of the excretory ducts of glands, the latter by circumscribed 

 softenings of the connective substance. The latter form, with 

 which alone we are now concerned, differs from mucous tissue in 

 its mode of origin. The cells take a less neutral, and more of 

 an active or passive, part in the process, in consequence of 

 which they may either assume greater mobility, appearing as 

 floating elements in tlie "fluid products of softening," or they 

 may undergo complete destruction. 



§ 43. Our ignorance of the conditions which determine the 

 occurrence of mucous softening is nearly absolute. Were' it not 

 for the fact that it converts things possessing a sliarply defined 

 anatomical form into substances which are amorphous, homo- 

 geneous, and capable of absorbing fluid, we miglit feel doubts 



