LEAD. 291 



panied frequently with severe and almost constant pain about 

 the navel, giving rise to what is named Colica pictonum. The 

 stomach is generally more or less disordered, the appetite is im- 

 paired, and there is sometimes, though not constantly, vomiting. 

 The skin has a dull, dirty, cadaverous appearance, and is often 

 bedewed with a cold clammy perspiration. The pulse is sometimes 

 retarded, but more commonly small and quick ; the respiration is 

 laborious ; tremors and debility of the voluntary muscles succeed, 

 and are often followed by partial paralysis, and in violent cases by 

 apoplexy. 



The best antidote to the soluble salts of lead, is a solution of the 

 sulphates of soda or of potash, as it immediately decomposes them, 

 producing an insoluble sulphate of lead, which is comparatively 

 inert. In the treatment of the colica pictonum, the principal 

 object is to allay the spasm, and to evacuate the bowels by mild 

 cathartics, particularly of sulphate of magnesia, or castor oil, com- 

 bined with opium. The plan of treatment usually adopted in 

 Edinburgh consists in giving a large close of some neutral laxative 

 salt, and, an hour afterwards, a full dose of opium. " Sometimes," 

 says Professor Christison, " alvine discharges take place before the 

 opium acts, more commonly not till its action is past, and occa- 

 sionally not for a considerable time afterwards. But the pain and 

 vomiting subside, the restlessness and irritability pass away, and 

 the bowels return nearly or entirely to their natural condition. 

 Sometimes it is necessary to repeat the practice. It is almost 

 always successful. I have never seen the second dose fail to 

 remove cholic, leaving the bowels at worst in a state of constipa- 

 tion. When the pulse is full and strong, I have seen venesection 

 premised with apparent advantage." Where all fluids are rejected 

 by vomiting, a pill of calomel, colocynth, and opium, may be 

 given, and a return of the disease is to be guarded against by the 

 constant use of some aperient medicine. 



Sulphuretted hydrogen, added to liquids containing lead, gives a 

 blackish precipitate, but a similar effect is produced when iron, 

 silver, and some other metals are present ; hence it cannot be 

 relied on as a test for discovering lead. The subcarbonate of 

 ammonia will precipitate lead from its solutions in the form of a 



