BLOOD. 117 



crease enormously in some anaemias, and especially in trichi- 

 nosis. 



2. (3 (amphophiU) granulations are colored both by acid and 

 basic dyes. They appear as very fine granules. They occur 

 in the bone-marrow, but not in the normal blood of man. They 

 are found, however, in the blood of guinea-pigs, rabbits, chick- 

 ens, etc. 



3. 7 granulations are quite coarse and stain in basic dyes. 

 Cells containing these are called Mastzellen, and occur very 

 seldom in normal human blood, but are abundant in leukaemia. 

 They are found usually in the blood of lower animals, and are 

 abundant in connective tissue. They can be stained best by 

 the violet basic dyes : dahlia, gentian-violet, methyl-violet, etc. 



4. <5 (basophile) granulations are fine granules, occurring 

 mainly in large rnononuclear leucocytes in human blood. 

 They stain in basic dyes, and especially well in methylene- 

 blue. 



5. e (neulrophile) granulations are small, and are colored 

 only in neutral dyes and with mixtures of acid and basic dyes 

 (e. g., acid fuchsin with methyl-green, or acid fuchsin with 

 methylene-blue). They are found in the great majority of 

 polymorphonuclear leucocytes. 



As to the nature of these different kinds of leucocytes, 

 various views are held. According to some, all are derived 

 from one common form, and are not to be considered as differ- 

 ent cells. Others claim that they are entirely distinct cell 

 types, and that each has a special organ to which it belongs 

 (e. g., lymphocytes in the lymph glands, rnyelocytes in the 

 bone-marrow, splenocytes in the spleen). 



Blood-platelets are small, colorless, round or ellipsoid bodies 

 of unequal size, usually about one-third the diameter of a red 

 blood-cell, first described by Hayem, Bizzozero, and Osier. 

 They possess no nucleus, and their place as independent mor- 

 phological constituents of the blood has been denied by many 

 authors. Some regard them as portions of other blood cells. 

 According to most writers, they play an important role in the 

 coagulation of blood. As soon as blood is shed, they disappear, 



