LEAD. 583 



Lead. 



The poisonous salts of lead in ordinary use are sugar of lead 

 (the acetate), white lead (the carbonate), and the subacetate em- 

 ployed in making lotions. Acute lead poisoning is very rare in 

 the horse; although the chronic form is not unfrequent. The 

 difference between the two depends on the amount and frequency 

 of the dose of poison taken. Young animals are far more easily 

 affected by any of the poisonous (soluble in water) salts of lead 

 than older ones. Cases of this form of poisoning may arise from 

 eating grass which has been grown under the influence of the 

 fumes given off by neighbouring lead-smelting works, or which 

 has been manured with slag obtained from these furnaces ; from 

 drinking water contaminated by lead pipes, lead cisterns, car- 

 bonate of lead (in putty, for instance), white lead paint, or other 

 compounds of lead ; or from eating lead — e.g., bullet spray, 

 scattered over grass near rifle butts. Although the causes which 

 render some kinds of water more liable than other kinds to dis- 

 solve metallic lead, are not very accurately known, the fact remains 

 that the presence of decomposing vegetable matter in water 

 greatly increases its power of dissolving that metal, in which 

 [irocess, bacteria may assist by forming an acid that makes a 

 soluble compound with lead. 



SYMPTOMS OF ACUTE LEAD POISONING.— Colic ; con- 

 stipation, or bad-smelling diarrhoea; cramps; depression; de- 

 lirium ; convulsions ; and paralysis. 



rRINCIPLES OF TREATMENT.— (1) Stop (especially in acute cases) the 

 action of the poison, which is necessarily in a soluble form, by converting 

 it into an insoluble compound. We can do this by the administration of 

 sulphuric acid, Epsom salts or Glauber salts ; the result being the greater or 

 less formation of the insoluble sulphate of lead. (2) Relieve, if present, the 

 constipation, which may also be effected by giving Epsom salts or Glauber 

 salts. It is evident that a laxative state of the bowels favours the 

 removal of the poison from the system. (3) Eliminate the lead which may- 

 have become deposited in the tissues. For this end, iodide of potassium is 

 particularly useful. (4) Combat the paralysis, which may be done by 

 strychnine and massage. (5) Allay pain, if present, by chloral hydrate or 

 ehlorodyne. 



SYMPTOMS OF CHRONIC LEAD POISONING.— Paralysis of 



the limbs ; cough ; difficulty in breathing ; roaring ; swelling of 

 the knees and fetlocks ; hidebound ; emaciation ; and impaired 

 appetite and digestion. There is no fever. In human beings 

 suffering from chronic lead poisoning, a blue or grey line (caused 

 by the presence of sulphide of lead) along the edge of the gums may 



