ABSCESSES. 193 



Suppuration may occur in any of the tissues of the body, but it is most 

 frequent in the glandular structures, the skin, muscles, and mucous mem- 

 branes. Cartilage and tendons suppurate only very slowly. Nerve 

 tissues and arteries are but little susceptible of taking on the process of 

 suppuration or of ulceration. Serous membranes, though they may 

 suppurate, yet, more generally, under the influence of inflammation exude 

 serum, or water, or lymph. 



Suppuration or the formation of pus may, according to circumstances, 

 be either a healthy or an unhealthy action, though it is in all cases a 

 morbid process. Suppuration may set in for various reasons. It may 

 be a means of removing some poisonous matter from the blood, or some 

 foreign substance impacted in the soft parts of the body. In all such 

 cases it serves a beneficial end, and must then be regarded as a healthy 

 action. 



A tendency to suppuration may also be generated by a disordered state 

 of the blood after some lingering and weakening illness, such as fever; 

 or it may be the result of inflammation caused by blows. In other cases 

 the tendency may be a consequence of breathing impure air, or of insuffi- 

 cient or bad food, or of disordered nutrition, or of any such causes which 

 produce impoverishment of the system. Under certain circumstances, 

 hereafter to be described, the suppurative matter forms abscesses. 



393. Healthy Pus. 



Pus is a peculiar fluid, formed under certain diseased conditions of the 

 system. Healthy pus is of a yellowish-white colour, free from offensive 

 smell, and of the consistence of cream. It consists of serum holding a 

 number of globules in suspension. Each globule consists of a cell wall 

 enclosing nuclei, oil globules, and small granules. Healthy pus is occa- 

 sionally reabsorbed into the system without producing any bad effects. 

 Nature sometimes cures an abscess in this way. 



394 Unhealthy Pus. 



There are several varieties of unhealthy pus. It usually has an offen- 

 sive smell. It is called sanious, when it contains blood ; ichorous, when 

 it is thin and watery; and muco-purulent, when it consists of mucus- 

 containing cells. Puriform matter is formed by the softening down of a 

 fibrinous exudation without the formation of true pus cells. If suppu- 

 ration is too profuse it will exhaust the vital powers. Unhealthy pus, if 

 reabsorbed into the system, will produce very injurious results. 



395. Mode of formation of an Abscess. 



The formation of an abscess takes place in the following manner. A 

 part from any cause, we will suppose, has become inflamed. In the 

 centre of the inflamed part the products effused by the process of inflam- 

 mation begin after a time to break up and liquefy ; or, in other words, 

 there are signs of the commencement of the suppurative process. 



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