THE BLOOD AND THE BLOOD-FORMING ORGANS. 373 



JEIydrajinia i that condition in which the blood contains a large_amojint 

 of jyalsi in proportion ^o the solid ingredients. It occurs in a variety 

 of diseases of the heart, lungsfliver, and kidneys, and characterizes all 

 forms of amemia. 



Hsemoglobinaemia. Owing to the destruction of red blood cells in some 



forms of poisoning, burning, etc., the blood plasma may contain free 

 haemoglobin,, by which it is discolored (Jt(cmogJobincemia), or it may be 

 stained from the absorption of Tfl'le pigment. 



The blood may be actually increased in volume (plethora), either by 

 an increase in fluids or in cells, or by simultaneous and proportionate 

 increase of both fluid and cellular elements. 



Ansemia. In general, auiemia means a diminished quantity of blood 

 or_of red blood cells in the vessels of the whoje_arjiny part of the body. _ 

 "Vyn^^ne^exception^jnJld chlorosis^- itTis invariably characterized by a 

 reduction in number and change in fornijpf the red cells (oligocythaeniia), 

 and by diminished alkalinity and coagulability. It is always associated 

 with a reduction in specific gravity, haemoglobin, and in solid elements. 

 Hydnemia and an increased tendency toward osmosis are equally con- 

 stant features of this condition. The albumens remaining in the serum 

 after coagulation are very slightly diminished in anaemia. 



Generally speaking, anaemia is produced by excesive_ iiaematolysis, 

 or by defective haematogeuesisT or by actual loss of blood, in *bulk (hsem- 

 orrhage), or in its fluid ingredients (transudation). 



Anaemia may be secondary to haemorrhage, to exudative processes, to 

 prolonged malnutrition, to clironic^organic diseases of many kinds, to_ 

 the action of poisons, to congenital hypoplasia of heart and arteries, to 

 functional disturbances of an unknown nature in the blood-forming 

 organs, and to wholly unknown causes. SimpleL_atrQrjhic changes in 

 many tissues, hypertrophy of the red marrow, lymph-nodes, spleen, liver, 

 and thymus, fatty degeneration of the liver, kidneys, heart, and blood- 

 vessels, with capillary haemorrhages and transudations, are frequent ac- 

 companiments of severe anaemia. 



ALTERATIONS IN THE BED BLOOD CELLS. 



These may be diminished in number and may undergo various 

 changes in shape and size and structure. 



ALTERATION IN NUMBER OF THE BED BLOOD CELLS. 



Oligocythgemia is that condition of the blood in whicli the number of 

 the red cells is reduced. This reduction in number may be temporary, 

 as after haemorrhage, or it may be persistent, as in some forms of anae- 

 mia. The number of red blood cells may in extreme cases of anaemia be 

 reduced to one-tenth of the normal, or even less ; that is, from the nor- 

 mal number, which is between four and five million, there may be a re- 

 duction to half a million or less. 



