30 MUCOUS SOFTENING. 



deoree from a slight, finely granular cloudiness, without any in- 

 crease in volume or alteration in shape of the cells, to a granular 

 opacity which entirely conceals the nuclear structures, and is 

 associated moreover with a very marked enlargement and filling 

 out of the corpuscular elements. The granular matter is dissolved 

 by acetic acid ; this renders it impossible to mistake the change 

 in question, at least in its earlier stages, for fatty metamor- 

 phosis. At a later period such a mistake is all the more likely 

 to occur, inasmuch as the cloudy swelling, unless checked at once, 

 the cells being restored to their normal condition by solution of 

 the contained granules, passes directly into fatty metamorphosis 

 and consequent disintegration. 



§ 37. The pathological significance of cloudy swelling was 

 interpreted by Virchow, who was the first to describe the process 

 (in the year 1850) as a nutritive irritation of the cells, i.e. 

 a stimulation of the cells to absorb an excessive amount of pabu- 

 lum. It is still admitted to be a consequence of the irritation of 

 cells ; and it is notorious that the direct action of various mineral, 

 veo-etable, and animal poisons is capable of producing cloudy 

 swelling of the glandular epithelia. (See Parenchj'matous Inflam- 

 mation of Liver and Kidneys. ) But the question whether the pro- 

 cess is active or passive in its nature tends more and more to be 

 answered in the latter sense; so that for my own part I am 

 inclined to suppose a kind of corrosive action, in consequence of 

 which the albuminous matters, held in solution by the protoplasm, 

 under n-o coagulation, and become visible as minute gi'anules ; the 

 phenomenon Ijeing in this respect analogous to rigor mortis. 



C. Mucous Softening. 



§ 38. Tliis constitutes another of the " conditions of involu- 

 tion" to which the tissues are liable. The group of changes 

 embraced under this head involve a gradual liquefaction of tissue, 

 rendered possible by the passage of the insoluble albuminous 

 matters which constitute the cellular and intercellular substance 

 into soluble modifications. Among the chemical compounds 

 which result from this transformation, mucus takes a prominent 

 place, inasmuch as its capacity of swelling by imbibition makes 

 it occupy a relatively large amount of space, and so renders it 

 conspicuous even to the naked eye. 



