CIRCULATORY SYSTEM. 125 



Hemolysis occurs in various diseases and is one of 

 the chief changes observed in making a Wasser- 

 mann test. 



The identification of blood-stains is often a medico- 

 legal problem. The corpuscles of the blood pre- 

 serve their integrity for a remarkably long period of 

 time, so that in a water solution of even an old clot, 



Germinal center. 

 Lymph sinus 



Fig. 89. Section of lymph node. 



the red blood-corpuscles are readily detected under 

 the microscope. Hemin crystals is another evidence 

 that the stain is blood. To identify the blood of 

 man is practically impossible. Non-mammalian 

 blood, as that of a bird, can usually be positively 

 recognized by the nucleated red blood-corpuscles 

 and their oval form. The practical value of this in 

 criminal cases is apparent. 



LYMPHATIC SYSTEM, THYMUS, AND SPLEEN, 

 i. Lymphatic Capillaries. The walls of these 

 capillaries consist of a single layer of flattened 

 epithelial cells (mesothelial or endothelial) . They 



