HEMOGLOBIN 



211 



The application of such a classification of stains to other tissues than 

 the blood, has, however, been found to present considerable difficulties. 



According to Kite the cytoplasm of the polymorphonuclear leukocytes 

 has nothing of the nature of a cell membrane, but they are completely 

 naked, nor do they contain a spongioplasm and hyaloplasm. "The cyto- 

 plasm is a jelly in which are embedded large numbers of globules." The 

 structures usually termed 

 cytoplasmic granules are of 

 the nature of separation 

 products ; they do not grade 

 into the surrounding cyto- 

 plasm. All leukocytes un- 

 dergo also certain definite 

 structural transformations, 

 characterized by the appear- 

 ance of pseudopods chang- 

 ing into vibratile cilia. Kite 

 suggests that the protoplas- 

 mic processes may be prom- 

 inently concerned in phago- 

 cytosis. Under certain con- 

 ditions erythroplastids may 

 be made to protrude similar 

 processes (Jour. Infect. 

 Dis., 15, 2, 1914). 



FIG. 225. OUTLINE DRAWINGS OF LIVING POLY- 

 MORPHONUCLEAR LEUKOCYTES OF RABBIT, 

 FROM A DROP OF BLOOD MIXED. WITH RINGER'S 

 SOLUTION TO WHICH A SMALL AMOUNT OF 

 HIRUDIN HAD BEEN ADDED TO PREVENT COAG- 

 ULATION. 



HEMOGLOBIN 



Hemoglobin is 



In the course of half an hour the cells develop 

 retractile undulatory processes, a, hyaline-sur- 

 face phase; x, hyaline layer; 6 and c, ciliated 

 phase; d, flagellated phase. Leukocytes of all 

 classes of vertebrates undergo similar changes. 

 (After Kite, Jour. Infectious Dis., 15, 2, 

 1914.) 



a very 



complex chemical compound 

 of iron with a globulin; it 

 gives the characteristic color 

 to the blood. It combines 



readily with oxygen to form oxyhemoglobin, a loose chemical combina- 

 tion by which the oxygen is carried from the lungs to the tissues, and 

 which gives the brighter red color to the arterial as compared with the 

 venous blood. The hemoglobin is held either in solution or in unstable 

 chemical union by the cytoplasm of the erythroplastids. It escapes from 

 these corpuscles after rupture, or it may be extracted by ether, and is 



