MERCURIAL OINTMENT AND VAPOR OF MERCURY. 61 
ing only 1 gr. of the oxide to jj. of fatty matter, I should consider 
this preparation as about equal in strength and action to the blue 
mercurial ointment. 
The result which we have obtained in regard to the blue oint- 
ment may also be extended to a series of other preparations which 
are made by the trituration of metallic mercury with various sub 
stances, but are destined for internal administration. Among these 
are the JEthiops per se, the Hyd. c. Cret. (P. L.), the Hyd. c. 
Magn. (P. Dubl.), the JEthiops graphiticus (P. Sax., Mercurius 
gummosus Plenckii, JEthiops saccharatus, JEtMops tartarisatus 
Sellii, Pil. Hydrargyr. (P. L.). As metallic mercury is no more 
able to penetrate the mucous membrane of the intestines than the 
skin, the action of these preparations can only depend upon the oxide 
they contain, which is formed by the trituration, and is dissolved by 
the free acid of the gastric and intestinal secretions. This view 
was confirmed by a preparation which had been made by triturating 
1 part of mercury with 2 of sugar for several hours. When treat- 
ed with water acidified with sulphuric acid, it yielded a solution 
which gave a brown turbidity with sulphuretted hydrogen. Most 
of these preparations have become obsolete on account of their un- 
certain and feeble action. Moreover, there can be no doubt that 
the very uncertain action of mercurial ointment does not depend 
merely upon the various susceptibilities of individuals, but also 
upon the varying quantity of oxide contained in it ; and as individ- 
uality always remains an incalculable quantity x, it would be advi- 
sable, with a view to obtain the most uniform effects, to substitute 
for the second x a constant magnitude, and to replace the blue 
ointment by an ointment containin-g the protoxide. 
II. The poisonous action of the vapor of mercury is well known. 
Small animals die in an atmosphere of it ; and man, when constantly- 
exposed to its influence by his calling, suffers sometimes fronrcoughs 
and bronchitic symptoms, sometimes from the peculiar mercurial 
tremors, sometimes from gingival affections, and other phenomena 
of mercurial cachexy. Although cases of the first kind are attribu- 
table to mere local irritation of the respiratory organs, the latter 
decidedly indicate absorption ; hence arises the question, Can the 
vapor of mercury penetrate animal membranes ? 
It is well known that a piece of gold suspended over a vessel 
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