74 INFLAMMATION. 
Macroscopically these tissues are hard, brittle and of a whitish color. 
Under the microscope the granules appear dark by transmitted light, 
and white and glistening by reflected light. 
Describe pigmentation. 
Pigment present in the body under abnormal conditions may be 
formed in the body or introduced from without. It occurs as yellow, 
brown, black, or reddish granules, and is found in the cells or the inter- 
cellular substance. Usually the pigment is formed from the hamo- 
globin of extravasated red-blood cells. Or, as in the pigmentation of 
dung tissue, it may be introduced from without the body by inhalation 
of particles of dust. 
INFLAMMATION. 
It is impossible to’ give an exact definition of the term inflammation, 
therefore the best that we can do is to confine ourselves to a consider- 
ation of the morbid changes to which this term is generally applied. 
How may the changes occurring in inflammation be classified ? 
Vascular changes, proliferative changes, degenerative changes, and 
finally, reparative changes. 
Describe the vascular changes of inflammation ? 
First, there is a dilatation of the arteries, veins and capillaries, with 
an increased rapidity of the blood current. Then, the blood current 
becoming slower, the white-blood cells accumulate in the veins and 
capillaries and stick to the vessel-walls. Then, by virtue of their 
amoeboid movement, the white-blood cells work through the vessel-wall 
into the surrounding tissue. Tlrey are followed by the red-blood cells 
in smaller numbers and by the blood plasma. 
What products, then, are found in tissue as the result of inflam- 
mation ? 
White-blood cells (which are here called leucocytes, or pus cells) ; 
red-blood cells, fibrin produced by the union of elements in blood 
plasma with white-blood cells; serum, the portion of the blood plasma 
left after the formation of fibrin. These different elements may occur 
in different proportions in different cases. 
What are the effects of this process ? 
Heat, redness, swelling, and pain. 
