606 OF NUTRITION. 



804. Should the Inflammation increase in intensity, a complete stagnation 

 of blood in the tissue most affected, or even in an entire organ, will be the 

 result; and this will occasion its death. If a large part be thus entirely de- 

 stroyed at once, the process is termed Gangrene; and it separates from the 

 living part, at a line where the Inflammation is less intense, and where there 

 is a deposit of Fibrine, which serves the important purpose of closing the 

 mouths of the blood-vessels that are laid open by the process. .If the destruc- 

 tion of tissue, however, be interstitial, the dead parts are not thus thrown off, 

 but are taken up by the absorbent process ; and thus the cavity of an Abscess, 

 or of an Ulcer is formed. This cavity is usually bounded by tissue, that has 

 been consolidated by the effusion of Fibrine ; a fact readily accounted for on 

 the principles just stated. For the death and removal of tissue take place, 

 where the Inflammation has been most intense and the stagnation most com- 

 plete, which is in the centre of the inflamed spot; and the fibrinous effusion, 

 the result of moderate inflammation, is poured into the surrounding tissue. 

 The elements of Liquor Sanguinis are poured into the central, as well as the 

 peripheral, portion of the inflamed tissue; but they assume a different form 

 that of Pus. It would appear as if the influence of the surrounding death and 

 decay produces a degradation of their character; so that they become entirely 

 aplastic or unorganizable, although immediately derived from Blood highly 

 charged with Fibrine. 



805. Between Coagulable Lymph and Purulent effusions, there are many 

 degrees of transition ; the very same deposit being frequently organizable at 

 one part, presenting the character of a tough fibrous membrane, interspersed 

 with corpuscles, whilst it is friable in another, from want of complete fibril- 

 lation in the fluid portion of the effusion, and is entirely destitute of tenacity 

 in a third portion, especially the superficial part, or free surface, of the deposit. 

 When examined by the Microscope, Pus is found to be characterized by the 

 presence of a number of cells of a peculiar, aspect, having a very tuberculated 

 or mulberry surface ; these are seen floating in a fluid, termed liquor puris, 

 which is of an albuminous or low fibrinous character, being entirely destitute 

 of organizability. Now the production of Pus in an inflamed part, or in other 

 words, the act of Suppuration, may be due to one of three causes, viz. the 

 intensity of the inflammation; the presence of air. which becomes a source of 

 irritation ; and a previously vitiated state of the blood. Various attempts 

 have been made to show that the Pus-globule is a degenerated red or white 

 corpuscle of the Blood ; it seems more probable, however, that it does not 

 escape from the vessels as a complete cell, but as a cell-germ, which may 

 have had its origin in a white corpuscle of the blood ; and which, under 

 favourable circumstances, might have produced an Exudation-corpuscle ( 800). 

 At any rate, it must be regarded as a degenerated form of cell ; and the liquor 

 /no-is must be considered as analogous to the plasma of the Blood in a de- 

 generated state. 



806. In what manner the Inflammatory process determines the formation 

 of the Pus-cell, and the consequent degradation of the product, we are at 

 present unable to state ; but that the degree of irritation in the part has an 

 influence upon it, is evident from the effects of the contact of air upon inflamed 

 .surfaces, causing those elements to take the form of Pus, which would other- 

 wise have been thrown out as a plastic deposit. This circumstance would 

 seem to indicate, beyond all doubt, that the Exudation and Pus-corpuscles, 

 the plastic Lymph and the aplastic Liquor puris have the same origin; but 

 that their character is determined by local circumstances. There is great 

 reason to believe, that when Pus is introduced into the Blood, it may induce 

 such a change in the character of the fluid, as speedily to impair its vital pro- 

 perties ; so that the Pus-corpuscles will rapidly propagate themselves in the 



