i6o Disturbances of the Blood. 



cytes, causes in ansemias large areas of this tissue to return to the 

 condition of red marrow (normally only young growing animals 

 have much red marrow ; in adults medullary blood formation is 

 limited to a few bones according to the amount of blood required 

 to be formed ; change of the marrow to the red state and pro- 

 duction of this condition in many of the bones may be brought 

 about in animals by venesection — Naunyn, Litten and Orth). 



In severe forms of ansemia not occasioned by actual blood loss the pro- 

 portion of iron in the liver, spleen and kidneys becomes abnormally high, this 

 feature invariably indicating exaggerated destruction of the red cells. 



From a variety of causes, particularly the influence of certain 

 poisons (salts of the biliary acids, snake venom, bacterial toxines) 

 and, too, the transfusion of heterogeneous blood (blood from a 

 different species of animal), the h?emoglobin may undergo solution 

 and separation from the erythrocytes into the plasma {hccnio- 

 globincemia) . The coloring matter thus freed gives the plasma 

 or serum a difl^use wine-red color. A portion of the haemoglobin 

 is taken up by the liver and transformed into biliary pigment, and 

 the remnants of the injured and therefore disintegrating blood 

 corpuscles are to be found in the liver and in the spleen (also in 

 the marrow), these organs sometimes becoming considerably swol- 

 len and excessive bile formation taking place. The bulk of the 

 liberated haemoglobin is removed by the kidneys, causing more or 

 less harm to these organs and giving to the urine a blood red to 

 black discoloration (hcemoglobincemia) . These changes are ob- 

 served not only in association with severe infections and intoxica- 

 tions in cattle, but are also seen after muscular strain and chilling, 

 especially in horses and, too, in human beings (infectious, toxic, 

 paroxysmal, myogenous, rheumatic hsemoglobinuria). Some of 

 the haemoglobin in hjemoglobinaemia which remains in the blood is 

 converted into methasmoglobin ; this change may also affect the 

 coloring matter within the corpuscles, and is apt to result par- 

 ticularly from the action of certain poisons (antipyrin, potassium 

 chlorate). It gives rise to an appreciable sepia-brown coloration 

 of the blood (niethcemoglobincemia) . There always coexist with 

 this group of blood changes serious diseases of the subject ; the 

 haemoglobin, freed from the cells and altered in its constitution, 

 useless for respiratory purposes, is no longer capable of taking up 

 and giving off oxygen (Krehl), and the disintegrating blood cells 

 give origin to substances which may cause coagulation to take 



