258 ANATOMY OF THE DOMESTIC FOWL 



bicarbonate of soda. The alkalmity of the blood is reduced by work. 

 This is due to the formation of sarcolactic acid in the muscle. The 

 odor of blood is due to volatile fatty acids. Each kind of fowl 

 has its own peculiar odor. The taste of the blood is saltish, due 

 to a small amount of sodium chlorid it contains. 



The blood consists of the following substances: 



First, the imorganized part, or fluid, the Uquor sanguinis or 

 plasma. It contains in solution proteids, extractives, mineral mat- 

 ter, and gases. The gases are held in loose chemical union. 



The liquor sanguinis constitutes fuUy 66 per cent, of the volume 

 of the blood. It is albuminous in nature and contains a small 

 amount of coloring matter of a fatty nature. It holds in solution 

 three proteids — fibrinogen, serum globulin, and serum albumin. 



Second, the organized parts, or the cellular structure (Fig. 74, 

 Nos. I to 21). The cells float in the plasma and consist of three 

 groups: the erythrocytes, or red blood cells, the leucocytes, or white 

 blood cells, and the thrombocytes. 



Erythrocytes. — The average nimiber of red cells (Fig. 74, No. 21) 

 of the domestic fowl range between 3,000,000 and 4,000,000 per 

 cubic milUmeter. The red blood cells are flattened and elliptical 

 in shape, and possess an oval elliptical nucleus. The average 

 length is J^ioo inch and the diameter J'^goo inch, or 7 to 8 micra 

 in diameter and 12 to 13 micra in length. However the diameters 

 vary in different kinds of birds. The cytoplasm is yeUowand glassy, 

 and the nucleus takes basic stains and appears somewhat picnotic. 



Thrombocytes. — The thrombocyte (Fig. 74, No. 19) is of about the 

 same length as the erythrocyte but somewhat narrower. The nucleus 

 is roimd, stains purple with the Wright's stain, and the chromatin 

 material is somewhat diffused. The diameter of the nucleus is 

 nearly equal to that of the cell. The cytoplasm is pale and may 

 show vacuoles near the nucleus. They may contain small circum- 

 scribed red structures. They vary somewhat in size and shape. 

 There are in the domestic fowl between 45,00a and 55,000 per cubic 

 milUmeter. 



Leucocytes. — There are, in the blood of the hen, 28,000 to 35,000 

 leucocytes per cubic millimeter. The leucocytes may be divided 

 into five distinct types. These are as follows: 



Polymorphonuclear leucocytes with eosinophihcrods (Fig. 74, No. 

 2) are round and have a diameter about equal to the length of the 

 erythrocyte. The nucleus is polymorphous; that is, it has two or 



