48 VETBEINAEY TOXICOLOGY 



number of milligrammes of lead dissolved by 500 c.c. of 

 water from a bright surface of 5,600 square millimetres : 



Such conditions are fulfilled by rain water, but ordinary 

 hard water is without perceptible solvent action. The lead 

 is at first dissolved by soft water, but eventually separates 

 in the form of white flakes of basic carbonate. 



Lead poisoning of cattle almost always results from 

 eating white paint or red lead, and of dogs by licking wet 

 paint, or by licking lead lotions applied externally. 



Absorption and Elimination. — With the exception of the 

 acetate, or sugar of lead, and the basic acetate, the prepara- 

 tions named above are insoluble in water, the oxides and 

 carbonate dissolving easily in dilute hydrochloric acid,* the 

 sulphate less readily, in conformity wherewith it has the 

 least toxicity, and its formation by the exhibition of dilute 

 sulphuric acid, or a soluble sulphate (Epsom or Glauber 

 salt), is an antidotal measure. 



It has been held that lead is absorbed as the chloride 

 formed by the action of the gastric juices. Lead salts, 

 however, precipitate albumins, and absorption as lead 

 albuminate is more probable. 



The relative insolubility of the lead salts and of the 

 albuminate account for the fact that lead is one of the least 

 corrosive metallic poisons. The question of poisoning by 

 metallic lead has been the subject of some controversy 

 {vide Eeferences), but is now held to be established. The 

 exposure of bullet splashes to weather leads to superficial 

 oxidation or rusting, whereby a coating soluble in acid will 

 be formed. In like manner, effluvise from lead- works may 

 eventually impregnate herbage, and lead from the refuse of 

 old disused workings gradually finds its way into the 



* It will be remembered that lead chloride is sparingly soluble. 



