] 2 INFLAMMATION. 



amceboid, and is as follows : — The mass constantly changes its 

 form. But as this goes on in all parts of the hyaline substance, 

 of which it consists, simultaneously, the only way in which it 

 can be understood is by confining the attention to one point 

 at a time ; it will then be seen that each act of movement begins 

 by the budding of a ray, or process of contractile substance in 

 a centrifugal direction. What next happens varies in different 

 cases. Sometimes the projection subsides just in the same way 

 as it was formed; at others, the finely granular fluid, which 

 occupies the more central parts of the corpuscle, streams into 

 the offshoot, gradually widening it out until it grows into a mass 

 greater than the remainder, which it finally draws into itself. 

 It is evident that the process last described must always be at- 

 tended with locomotion, for each time it is repeated the whole 

 mass rallies round a new centre, the position of which cor- 

 responds to the extremity of the offshoot. 



As already stated, these white corpuscles accumulate in large 

 numbers in the vessels of the inflamed part in close contact with 

 the walls. They then sink into the substance of the walls, and 

 pass through them into the surrounding tissue. During this 

 process it is seen that the corpuscle pierces the walls of the 

 vessels by means of prongs of a delicate homogeneous material, 

 similar at first to a shining thread. Some of these prongs pro- 

 ject, and as a prong increases in length it thickens at its base ; 

 the substance of the corpuscle now tends towards it, becoming 

 smaller as the prong gets larger ; in fact, the contents of the 

 corpuscle are drawn into the substance of the prong, which be- 

 comes rounded otf at its tip, and finally assumes the contour of 

 the corpuscle. Having escaped from the vessels into the sur- 

 rounding tissue, the corpuscles continue their active movements, 

 and increase rapidly in number. 



Yirchow describes two forms of inflammation, namely — (1st.) 

 The jparenchymatous inflammation, w4iere the process runs its 

 course in the interior of tlie tissue elements (e.g., connective 

 tissue cells, or germ masses, hepatic and cartilage cells), with- 

 out one being able to detect the presence of any free fluid which 

 has escaped from the blood ; and {2d) The secretory (exudative) 

 inflammation of superficial tissue elements, where an increased 

 escape of fiuid takes place from the blood, and conveys the new 

 products of growth and altered secretion with it to the surface. 



