S86 ARSENIC, ANTIMONY AND PHOSPHORUS 



and somewhat deliquescent in moist air; soluble in 1.2 parts of 

 water, slightly soluble in alcohol. 

 Preparations and Doses. 



Sodii Arsenas. H. gr. iij — vij ; 0.2 — 0.5. D. gr. %4 — 342 ; 

 0.001—0.005. 



Sodii Arsenas Exsiccaius — Dried Sodium Arsenate. The same 

 as the above salt with the water of crystallization driven off. About 

 twice the strength of the preceding. It occurs as' an amorphous 

 . white powder, odorless, and having a mild alkaline taste. Per- 

 manent in dry air. Soluble in 3 parts of cold water, freely soluble 

 in boiling water, sparingly soluble in alcohol. Doses, one-half those 

 of the preceding salt. 



Liquor Sodii Arsenaiis, Solution of Sodium Arsenate, Pearson's 

 Solution. One per cent, solution of exsiccated sodium arsenate in 

 water. Doses, same as for Fowler's solution. 



External and Local Action. Arsenic is antiseptic but is too 



toxic to be used for this purpose, although it is used to retard post- 

 mortem changes and in dilute solution as a parasiticide. (Dip for 

 sheep.) It is not absorbed from the skin when in dilute solution, 

 but there is reason to believe that it may be absorbed when in con- 

 centrated solution. Arsenic is irritant to mucous membranes and 

 raw surfaces, causing painful destruction of the tissue and if applied 

 over large surfaces or packed in wounds and cavities it may be 

 absorbed sufficiently to cause poisoning. 



Digestive System. It is generally believed that small doses of 

 arsenic stimulate the appetite and digestion. Large doses are irri- 

 tant, causing nausea, vomiting, abdominal pain, and diarrhea. The 

 irritant effects appear to be produced after absorption, because they 

 occur late and even after the drug has been administered subcutan- 

 eously. Large hypodermic doses cause edema of the intestines on 

 account of increased permeability of the capillaries, together with 

 degeneration and exfoliation of the intestinal epithelium. 



Circulatory System. Therapeutic doses may slightly increase 

 the pulse rate. Larger therapeutic doses tend, after a few days, to 

 cause edema of the skin and digestive tract, as shown by puffiness 

 around the eyes or other parts of the body, or by general dropsy, 

 nausea, or diarrhea. This is believed to be due to an increased per- 

 meability of the capillaries. The blood pressure is little influenced 

 by therapeutic doses but may fall after toxic ones on account of the 

 loss of serum by transudation. 



Blood. Arsenic appears to show its most valuable action upon 



the blood and blood forming organs. When administered for long 



periods to young growing animals, the bone marrow becomes more 



vascular, with an increase in the leucocytic elements, decrease in 



■ fat, and little if any change in the erythrocytic elements (Charteris), 



