THE BLOOD. 249 



this disease the relative proportion of red corpuscles is less 

 than normal. 



The normal color of blood serum is a light golden 



.yellow (straw color) . After the destruction or breaking down 

 of a large number of red corpuscles their coloring matter is 

 dissolved in the plasma of the blood and is partially converted 

 into methemoglobin. This causes a reddening of the serum 

 (Hemoglobinemia). The presence of the coloring matter of 

 the muscles may produce a similar result. 



Diseases of the Blood. 



Essential (idiopathic) anemia. Bloodlessness. Consists in a 

 diminishment of the quantity of blood without a determinable 

 cause. Blood pale and coagulates poorly. Mucous membranes 

 pale and low temperature. Pulse small, heart tones metallic 

 sound. Appetite poor. Tendency to dropsical swellings. General 

 weakness. Mostly in young animals. 



Leucemia. Chronic alterations of the blood and increase in 

 number of white corpuscles. Animals are languid, lazy, sweat easily, 

 pale mucous membranes. Appetite grows less, pulse increases, small. 

 Heart tones, metallic sound. Enlargement of lymphatic glands usually 

 present. Sometimes ecchymotic hemorrhages in the mucous mem- 

 branes. 



Infectious anemia of the horse. Transmissible, usually fatal 

 disease, course acute or chronic. Fever, 40.5° C. [104.9° F.] appears 

 after a period of incubation of 5-9 days, subsiding as the disease ad- 

 vances. Marked weakness, especially in hind quarters, dirty yellow- 

 ish red conjunctiva, some petecheae. Impaired appetite, emaciation, 

 swellings. Red corpuscles reduced in numbers. 



Hemoglobinuria of cattle. An acute non-contagious infec- 

 tious disease of cattle caused by the presence of the protozoon 

 Pyroplasma bigeminum in the blood, and characterized by hemo- 

 globinuria. About 12 days after the animals have been on an in- 

 fected pasture, the first symptoms appear — fever, loss of appetite, 

 diarrhea. Urine light to dark red, very foamy, urination painful. 

 Urine contains hemoglobin and coagulates into a gelatinous mass 

 when boiled. Gait stiff and clumsy, often attended with pain. 

 Also anemia, icterus, general debility, continuous lying down, 

 edematous swelling of head and neck. 



The cause of the disease is found in the blood in the form of 

 a protozoon called Pyroplasma bigeminum. The latter has a 

 roundish form which may become very irregular as a result of 

 ameboid movement. 



When fully developed they are found in the red corpuscles in 

 the form of two pear shaped bodies with the narrow ends ap- 



