I6O APPLIED PHYSIOLOGY 



281. The spleen. The spleen or milt is a soft red 

 organ, shaped like a tongue, lying just to the left of the 

 stomach. It is composed of small cells and fibers, among 

 which the blood circulates as through a sponge, without 

 being held within firm walled tubes. The spleen is sup- 

 posed to form the red blood cells, but they are also formed 

 in the marrow of bones. The spleen can be removed with 

 but little harm to the body. The pain in the side caused 

 by running is often due to an excess of blood in the spleen. 



SUMMARY 



1. Blood is composed of a liquid called plasma, in which 



float great numbers of extremely small red cells, and 

 fewer white cells. 



2. The red cells carry oxygen from the lungs to the cells 



of the body. 



3. The white cells repair injuries to the body. 



4. The plasma contains albumin and mineral matters, 



both of which are food for the cells of the body. 



5. The soda of the plasma carries carbonic acid gas to the 



lungs. The gas is there given off in the breath. 



6. After standing outside of the body for a few minutes, 



some of the albumin hardens to a stringy mass and 

 entangles the cells, forming a clot. 



7. All animals possess a fluid somewhat like man's blood. 



8. The spleen is a soft organ in which red blood cells are 



formed. 



DEMONSTRATIONS 



64. Set aside a spoonful of chicken's blood to clot. In a few hours the 

 serum will begin to separate. Breathe on a slide and place a tiny drop 

 of fresh chicken's blood upon it, cover it with a cover glass and exam- 

 ine it with a microscope magnifying at least 200 diameters to see the 

 red blood cells. Notice their oblong shape and their nuclei. 



