258 Inflanunation. 



cupied by the proliferating connective tissue. The formation of 

 thick, keratous epidermal layers (keratoses) over callosities of the 

 skin or inflamed and distended bursje is to be ascribed less to the 

 direct influence of external pressure than to the pressure exerted 

 from beneath by the hard and thickened cutis upon the epiderm 

 (see also chapters on Regeneration and Inflammation). 



The occurrence of congenital hypertrophies of certain parts of the 

 body may be due to a number of causes. Some examples are compen- 

 satory hypertrophies, as when one kidney fails to develop the other grows 

 to unusual size; others are due to chronic passive hyperemia in the foetus 

 caused by constrictions by amniotic bands, as the hypertrophy of the pinna 

 of the ear or of the penis, (cf. Chapter on i\ialformations, Spcziellc 

 patJiol. Anatomic der Hausticre, I Bd.). 



Inflammation. 



The term inflammation is applied to a condition of local irrita- 

 tion of the tissues, the seat of some type of injury, in which there 

 occur, as phenomena of reaction to the irritant, changes in the 

 blood current and lymphatic floiv, exudation of the constituents of 

 the blood, excessive secretion of glands, phagocytosis and prolifer- 

 ation of the tissues. 



In dealing with inflammation we have to do with a series of 

 processes which are nothing more than modifications and exaggera- 

 tions of physiological procedures, in this case having for their ob- 

 ject the defense of the organism against the harmful influences and 

 the compensation for local disturbances of nutrition, and represent- 

 ing abilities of the animal organism acquired through phylogenetic 

 adaptation. (Leber, Aletschnikoff, Diirk, ]\Iarchand, Schmauss and 

 otliers). 



In the lowest unicellular organisms, as the amcebae, the phe- 

 nomena of reaction to harmful influences are manifested by the 

 properties of chemotaxis, phagocytosis and intracellular digestion. 

 In the more highly organized forms of life, made up of dififerentiated 

 cells, these defensive functions are assumed by certain groups of 

 cells (Diirk) ; and in conformity with the complexity of structure 

 and interdependence of tissues and organs and the variability of 

 the injuries, these regulative and reparatory processes are made up 

 of a number of separate phenomena which in their synchronous 

 and consecutive operations are grouped together under the com- 

 prehensive term, inflammation. 



In the class of harmful agents capable of inducing inflammation, 

 the causes of intlannnation or irritants, are included a great variety 



