ARSENI TRIOXIDUM — ARSENIC 387 



There is no change in the number of red cells or in the percentage 

 of hemoglobin in the blood. Charteris found, " From repeated 

 doses large enough to produce cachexia and emaciation in rabbits, the 

 bone marrow undergoes hyaline degeneration accompanied by a de- 

 crease in the red cells and hemoglobin." 



Arsenic, therefore, tends to increase the leucocytic forming ele- 

 ments of the bone marrow and the leucocytes in the blood, but in 

 serious cases of chronic poisoning, it causes degeneration of the 

 marrow cells, wasting and anemia. It often increases the number 

 of red cells in pernicious anemia of man and diminishes the num- 

 ber of leucocytes in leukemia. How this action is accomplished can- 

 not be stated, but some suggest that it may act upon a parasite or 

 toxin. 



Nervous System. Clinical experience indicates that arsenic, 

 in therapeutic doses, is a stimulant to the nervous system. Nervous 

 disturbances occur in both acute and chronic poisoning, but more 

 especially in the latter. The paralysis is usually a polyneuritis, 

 similar to that caused by other poisons, although a few cases of 

 spinal paralysis have been observed. 



Bone. In young growing animals in poor condition, arsenic 

 tends to increase the density of the bone. There is no reason to be- 

 lieve that it has any such action in adults. 



Metabolism. There is a general belief that medicinal doses of 

 arsenic will favorably influence nutrition, but this action cannot be 

 explained except for the fact that the capillaries of the splanchnic 

 area are rendered more permeable. Toxic doses increase proteid 

 disintegration, increase the output of nitrogen, lessen oxidation and 

 cause fatty degeneration of the epithelium of the digestive tract, 

 liver, heart and kidneys. 



Absorption and Elimination. Absorption is fairly rapid 

 from the stomach and intestines if the drug is in solution. Elim- 

 ination is slow. Most of the drug passes out. by the kidneys, but 

 small amounts are excreted by most of the other excretions. 



Skin. Arsenic has a beneficial action upon the skin. In man 

 this is sh(3wa by an increase of subcutaneous fat and improvement of 

 the complexion. It also renders the coat of animals thicker and 

 more glossy. Its action here cannot be explained, although two 

 theories have been advanced. 1. That it has a specific action upon 

 the skin during its excretion, or 2, that it may increase the lymph 

 flow to the part. There is considerable evidence which would sup- 

 port either theory. There is a tendency to pigmentation of the skin 

 from long use of the drug. 



Tolerance. The system may be educated to stand large doses 

 of arsenic if the drug is started in small doses, and gradually in- 

 creased. After being so treated for a number of days, often months, 

 it is found that animals will show no physiological reaction to doses 



