504 



ANGIOLOGY 





the structure of the erythrocytes. The older view, that of Rollett, supposes that 

 the corpuscle consists of a sponge work or stroma permeated by a solution of hemo- 

 globin. Schafer, on the other hand, believes that the hemoglobin solution is con- 

 tained within an envelope or membrane, and the facts stated above with regard 

 to the osmotic behavior of the erythrocyte support this belief. The envelope 

 consists mainly of lecithin, cholesterin, and nucleoprotein. 



The colorless corpuscles or leucocytes are of various sizes, some no larger, others 

 smaller, than the red corpuscles, In human blood, however, the majority are 

 rather larger than the red corpuscles, and measure about lOju in diameter. On the 

 average from 7000 to 12,000 leucocytes are found in each cubic millimetre of 

 blood. 



Fid. 454. Varieties of leucocytes found in human blood. Highly magnified. 



They consist of minute masses of nucleated protoplasm, and exhibit several 

 varieties, which are differentiated from each other chiefly by the occurrence or 

 non-occurrence of granules in their protoplasm, and by the staining reactions of 

 these granules when present (Fig. 454). (1) The most numerous (60 per cent.) and 

 important are irregular in shape, possessed of the power of ameboid movement, 

 and are characterized by nuclei which often consist of two or three parts (multi- 

 partite) connected together by fine threads of chromatin. The protoplasm is 

 clear, and contains a number of very fine granules, which stain with acid dyes, 

 such as eosin, or with neutral dyes, and are therefore called oxyphil or neutrophil 

 (Fig. 454, P). These cells are termed the polymorphonuclear leucocytes. (2) A 

 second variety comprises from 1 to 4 per cent, of the leucocytes; they are larger 

 than the previous kind, and are made up of coarsely granular protoplasm, the 

 granules being highly refractile and grouped around single nuclei of horse-shoe 

 shape (Fig. 454, E). The granules stain deeply with eosin, and the cells are there- 

 fore often termed eosinophil corpuscles. (3) The third variety is called the hyaline 

 cell or macrocyte (Fig. 454, H). This is usually about the same size as the eosino- 

 phil cell, and, when at rest, is spherical in shape and contains a single round or 

 ova^l nucleus. The protoplasm is free from granules, but is not quite transparent, 

 having the appearance of ground glass. (4) The fourth kind of colorless corpuscle 

 is designated the lymphocyte (Fig. 454, L], because it is identical with the cell derived 

 from the lymph glands or other lymphoid tissue. It is the smallest of the leuco- 

 cytes, and consists chiefly of a spheroidal nucleus with a very little surrounding 

 protoplasm of a homogeneous nature; it is regarded as the immature form of the 



