25 
on Wolf Creek, Iowa. A fine pink pearl was found near 
Walla Walla, Washington State, and a number have been 
sold at Seattle, Washington. 
One of the most singular circumstances connected with 
the New Jersey ‘‘ pearl fever’’ of 1856 was the discovery 
of several shells which proved that the local savants had 
experimented on the pearl-bearing Unios by dropping 
mother-of-pearl buttons inside the shell, hoping that the 
mussel would cover them with its secretions. The speci- 
mens found had apparently been experimented on over 30 
years before, at a time when European scientists were 
greatly interested in shells received from China, contain- 
ing small images of Buddha. These images were moulded 
in tin and placed between the mantle and the shell. The 
mussels were then returned to their natural environment, 
and after several months the layer of mother-of-pearl be- 
came of sufficient thickness, and the images were removed. 
In a shell of the Lea Collection of Unionidze, which has 
recently been presented to the United States National 
Museum, an oval piece of white wax, flat on the lower 
side and rounded on the upper, which had been inserted in 
the valve near the hinge, is entirely coated with a pink 
nacre. It has been broken out of the shell, the pearly 
nacre of the lower or flat side remaining in the shell ; 
whereas the dome-shaped piece is covered with this ma- 
terial. 
The writer knew a New York lady who purchased a 
button-shaped Unio pearl that had a black, diseased ap- 
pearance on one side. It was so set that the imperfection 
was all below the mounting. When applauding at the 
opera one evening, the pearl was broken, and upon exam- 
ination it was found to consist of a very thin nacreous 
layer, inside of which was nothing but a hard, white, 
greasy clay. 
At the International Fisheries Exhibition held in Berlin 
during 1880, there were shown results of experiments under- 
