THE SERUM 135 



newt's blood the changes are especially noticeable in a variety of 

 colorless corpuscle, which consists of a mass of finely granular protoplasm 

 with jagged outline and contains three or four nuclei, or in large irregular 

 masses of protoplasm containing from five to twenty nuclei. 



The blood leucocytes are the phagocytes of the body. By means 

 of their ameboid movements they surround or engulf foreign bodies 

 including bacteria. These they digest, therefore destroy. It is through 

 the activity of the leucocytes that the body gains its relative immunity, 

 since these cells are able to overcome to a certain extent bacterial invasion. 

 The blood largely depends on the polymorphonuclear leucocytes for 

 phagocytosis, hence these cells are found to be increased in number under 

 the stimulus of infectious processes. The relative numbers of leucocytes 

 in clinical blood counts have their value in part in this fact. However, in 

 clinical bloods many pathological types appear which are of special 

 significance. 



The Blood Platelets or Thrombocytes. A third variety of corpuscle 

 found in the blood is known as the blood platelets. They are circular or 

 elliptical in shape, of nearly homogeneous structure, and vary in size from 

 0.5 to 5/-1/A. Hence they are smaller than the red corpuscles. They vary 

 in number from 5,000 to 45,000 per cubic millimeter and are preserved 

 by drawing fresh blood directly into Hayem's or other preserving fluid. 

 When fresh blood is drawn the blood platelets, coming in contact with 

 foreign bodies, rapidly disintegrate and give rise to one of the antecedents 

 of blood plasma concerned in clotting, prothrombin, p. 121. 



CHEMICAL COMPOSITION OF THE BLOOD. 



The chemical composition of the blood as a whole may be presented 

 by consideration of the constituents of the plasma and of the corpuscles. 

 The available blood analyses have dealt with whole blood, with either 

 plasma or serum and with whole corpuscles, although separate analyses 

 of red and white corpuscles have been made. 



The classical analyses in the literature that have become the reliance 

 for teaching purposes are those of Schmidt for the blood of man and of 

 Abderhalden for dog's and horse's blood. These analyses are quoted in 

 tabular form below. 



ANALYSES OF BLOOD OF MAN KARL SCHMIDT 



One Thousand Grammes of Blood. 



Blood- Corpuscles 513 . 02 



Water 349 -69 



Substances not vaporizing at 1 20 163 . 33 



Hematin 7 -7 (including 0.512 iron) 



Blood casein, etc 151 .89 



Inorganic constituents 3-74 (excluding iron) 



