HYDRARGYRUM. 89 



(5) Solutions of the perchloride (albuminates or peptonates) 

 may be injected hypodermically a powerful method, but apt to 

 produce sores. 



(6) The vapour of mercurials may be inhaled, as we have 

 seen ; but this method is rarely employed intentionally. 



(7) Mercury may be given per rectum, as the officinal sup- 

 positories. 



The action of mercury admitted to a part of the body by 

 any of these channels is usually more than local, the specific 

 effects of the drug, presently to be described, being shortly 

 developed. At the same time, the local effect will be more 

 marked : skin diseases will be healed, condylomata removed, 

 and indurations and chronic inflammatory processes reduced in 

 connection with the bones or joints. 



Internally. The local action of mercury is the same as 

 externally, according to the nature and strength of the prepara- 

 tion employed. Very dilute solutions of the perchloride (4 gr. 

 to 10 fl.oz., with 8 min. of hydrochloric acid) may be used as a 

 gargle or wash for syphilitic ulcers of the tongue and gums.g 

 All the salts of mercury act upon the mouth, gums, and salivary 

 glands, causing salivation ; but this effect is due to their excre- 

 tion, not to their immediate influence on the parts, and will be 

 described later. 



In the stomach, mercurials combine with the chloride of 

 sodium of the secretions, and, whatever their original form, are 

 converted into a double chloride of sodium and mercury, which 

 further unites with the albuminous juices, to form a complex 

 molecule of mercury, sodium, chlorine, and albumen. This 

 compound, although precipitated at first, is soluble in an excess 

 either of chloride of sodium or of albumen; exists in the 

 stomach, therefore, in solution ; and is readily diffusible and 

 easily absorbed. It is not specially irritant in moderate quan- 

 tities, and none of the salts of mercury given in medicinal doses 

 produce vomiting like zinc and copper ; indeed, Dr. Ringer lias 

 shown that calomel in T Vgr. doses, or Hydrargyrum cum Greta 

 in ^-gr. doses, given every two or three hours, arrests some forms 

 of vomiting in children. In large or concentrated doses, how- 

 ever, mercurials are irritant or corrosive to the stomach, and 

 must be given with caufion, after meals. 



The irritant effect of mercurials continues in the duodenum, 

 naturally taking the form of purgation. The perchloride is 

 never employed to produce this effect, but divided mercury in 

 the form of the Pilula Hydrargyri and Hydrargyrum cum Greta, 

 and Calomel, are common purgatives. The action of mercurials 

 as purgatives is a purely local one, none of the metal li-ini* 

 absorbed, but the whole expelled in the fieces. The exact 



