198 A. Pedler — Volatility of soma of the Compounds of Mercury. [No. 2, 



previously, and to save it from destruction it bad been pn^intod witli oil- 

 paint to which some cori-osive sublimate had been added. The staircase 

 was removed, and soon the normal conditions returned. The other in- 

 habitants had suffered much less or not at all ; from which it appears 

 that some persons are more liable to mercurial poisoning than others.' 



" ' The other instance is the following : — A landowner had poisoned 

 I'ats by means of corrosive sublimate, the rats chiefly infesting his 

 stable. His coachman, a sober and robusi young man, who used to sleep 

 in the stable, became pale, lost his appetite and easily got tired. When 

 on a visit at the gentleman's, the writer happened to see the servant, 

 and when on his advice the boards were taken up the remains of 40 

 i-ats were found. The foundations were renewed, fresh sand being used 

 for the purpose ; all holes in the walls were closed with cement, and the 

 servant was soon cured.' Here the corrosive sublimate was prevented 

 to a certain extent from evaporating by the ammonia disengaged from 

 the dung ; the doors of the stable remained open during the warmer 

 part of the day, and nevertheless the servant was poisoned by the mer- 

 curial vapour. These two cases ought to suffice to prove that mercuric 

 chloride is a dangerous and malicious enemy." 



Hager in his paper apparently traces these cases of poisoning 

 principally to the small particles of solid mercuric chloride which may 

 Lave been mechanically thrown off into the air, but, in view of the un- 

 doubted volatility of this salt in the solid state and even at ordinary 

 atmospheric temperatures, it is much more probable that the poisoning was 

 produced simply hj the vapour of mercuric chloride. It might of course 

 be argued that the amount of mercuric chloride vapour would be so 

 small as to bo unable to produce mercurial poisoning, but mercuric 

 chloride is certainly as volatile as mercury is itself, and there is a case on 

 record proving that mercury gives olf sufficient vapour at the ordinary 

 temperature of the air to cause salivation. This is described by Bur- 

 nett.* Uo says, " A ship on the Spanish coast was carrying a cargo of 

 mercury Some of the mercury had escaped from the packages and got 

 into the hold. All the exposed metal surfaces in the ship appear to have 

 become coated with mercury in consequence, and the whole ship's 

 company were effected with violent symptoms of salivation." 



If therefore sucli cases of mercurial poisoning as are described by 

 Hager, can take place from the use of mercuric chloride at European 

 air temperatures, the very greatest care should be taken in a country 

 like India whore such violently poisonous substances as mercuric chloride 

 are used in preserving books from the attacks of insects, as a vermin- 



* I'hils. Ti-aus. 1823, V. 402. 



