the nineteenth century. In 1867 Andreas Eigner treated Holbein’s Solothurn
Madonnawith mercury chloride (Brachert 1972:6). In Austria in 1911,
many altarpieces were totally impregnated with mercury chloride, a strong
poison that was recommended until the 1950s (Aberle and Koller 1966:7).
Many soluble salts were tested in combination with arsenic. Acids were
thought to be effective mainly against fungi (Schiessl 1984:12; Unger
1988:48), as were some alkaloid mediums. Concoctions of tobacco leaves,
blackthorn, pepper, bay leaves, aloe, myrrh, and garlic were believed to kill
woodworms (Schiessl 1984:13).210 Schiessl
a b
c d
e f
Figure 10a–f
Splitting of panels for conservation reasons,
done in 1957 (Schmidt-Thomsen 1957). The
very degraded support of a double-sided
painting urged partial transfer of the paint-
ings, as follows: (a) first, slits were made with
a circular saw; (b–d) the phases of splitting
followed; (e, f ) then the two thinned panel
parts were mounted on new auxiliary sup-
ports of chipboard.