IXFLAM:NLiTION. 



[ 413 ] 



INFLAMMATION. 



to exhibit active movements. They may 

 multiply by diAisiou, and thus rapidly in- 

 crease in numbiT: this will be again referred 

 to when spealving of pus. 



Not only is there a migration of colour- 

 less blood-corpuscles in iniiammatiou, but 

 the red corpuscles also pass through the 

 walls of the blood-vessels, though in less 

 considerable numbers ; and their transit is 

 mainly through the walls of the capillaries. 

 This passage of the red corpuscles takes 

 place in simple mechanical congestion ; and 

 it may be observed in the web of a frog in 

 which congestion has been artificially in- 

 duced by ligature of the femoral vein. 



Associated with the passage of the blood- 

 corpuscles through the walls of the vessels, 

 is an exudation of the liquor sanguinis. 

 The exuded liquor sanguinis, which con- 

 stitutes the well-known inflammatory effu- 

 sion, differs from the liquid which tran- 

 sudes as the result of simple mechanical 

 congestion, inasmuch as it usually contains 

 a larger proportion of albumen and fibrine, 

 a proportion which increases with the inten- 

 sity of the inflammation. It also contains 

 an excess of phosphates and carbonates. 



The most characteristic feature of inflam- 

 matory eftusion is the large number of cell- 

 structures W'hich it contains. These are in no 

 case generated spontaneously in the eflused 

 liquid. Most of them are migrated blood- 

 corpuscles ; and others are derived from the 

 proliferating elements of the original tissue. 

 The quantity and nature of the eflusion will 

 thus vary with the particular tissue in- 

 flamed, and with the severity of the in- 

 flammatory process. In non-vascular tissues, 

 as cai'tilage and the cornea, exudation can 

 only occur to a small extent from the neigh- 

 bouring vessels, and hence the effusion is 

 small in quantity. In dense organs, as the 

 liver and kidney, owing to the compactness 

 of the structure, a large amount of eftusion 

 is impossible ; and what there is, is so in- 

 termingled with the structural elements of 

 the organ, that it does not appear as an 

 independent material. In the kidney, it 

 escapes into the urinary tubes and so appears 

 in the urine. The effusion is most abundant, 

 and constitutes an important visible con- 

 stituent of the inflammatory process, in in- 

 flammation of those organs which possess 

 a lax structure and in which the vessels are 

 but little supported, as the lungs, and in 

 tissues which present a free surface, as mu- 

 cous and serous membranes. 



3. The remaining constituent of the in- 



flammatory process consists of an alteration 

 in the nutrition of the inflamed tissue. The 

 nutritive changes, although they may differ 

 according to the structure of the part, are 

 all characterized by an increase in the 

 nutritive activity of the cellular elements. 

 The nature of these nutritive changes has 

 for the most part been ascertained by the 

 investigation of tissues in the lower ani- 

 mals, in which inflammation has been arti- 

 ficially induced. In man the study of the 

 primary tissues is difficult, owing to the 

 fact that the process can rarely be observed 

 in its earher stages. The alteration in 

 nutrition, as already stated, is characterized 

 by an exaltation of the nutritive functions 

 of the cellular elements of the tissues in- 

 volved in the inflammatory process. This 

 is evidenced by an increase in the activity 

 of those elements which normally exhibit 

 active movements, as the amoeboid cells of 

 connective tissue and of the cornea. Cells 

 which, under normal circumstances, undergo 

 no alterations in form, and exhibit no active 

 movements, become active, sending out 

 processes and undergoing various alterations 

 in shape. This increase in the activity, 

 and variation in the form of the cells is in 

 most cases followed by enlargement and 

 division of their nuclei and protoplasm, and 

 thus by the formation of new cells. 



The increased activity of the cellular 

 elements varies considerably in different 

 tissues, and even in the elements of the 

 same tissue. Some cells exhibit active 

 movements, and form new cells, much more 

 readily than others. Those tissues, for 

 example, which naturally maintain them- 

 selves by the multiplication of their ele- 

 ments, as the epithelial tissues, become 

 active veiy readily in inflammation, slight 

 degi-ees of irritation being sufficient to 

 cause in them rapid cell-proliferation. 

 This is seen in inflammation of mucous 

 membranes, and of the epidermis. In tis- 

 sues, on the other hand, whose elements 

 normally exhibit no tendency to multipli- 

 cation, as corhmon connective tissue, carti- 

 lage, and bone, active changes are much 

 less readily induced ; the cells are much 

 more stable, and multiply with fai* less 

 facility. Lastly, in the higher tissues the 

 stability of the elements reaches its maxi- 

 mum, and in nerve-cells no increase of 

 activity can be induced. Different cells in 

 the same tissue exhibit also different degrees 

 of stability. In common connective tissue 

 and the cornea, for example, the amoeboid 



