PEARLS AND PEARL FISHERIES. 
411 
presented by some; and several writers send observations of ratber curious interest. 
Only 51 of tbe papers answer the question at all, of which 30 pronounce more or less 
positively in support of the intrusion theory, as above mentioned ; 8 are doubtful or 
non-committal; and 8 advocate the view that pearl production is due to injury or 
disease. Three papers (Illinois and Tennessee) state that the pearls are at first soft 
or gristly and acquire hardness and luster gradually later; and one from Texas reports 
finding them in various stages of growth before they were “glazed over. 77 The 
Florida paper, while accepting the intrusion theory, claims that all valuable pearls are 
formed upon an egg which the mollusk has not succeeded in extruding. This sug- 
gestion might easily be thought to afford explanation of the peculiar statements in 
the four papers just referred to. 
Interesting notes are given in an Indiana response, where the writer speaks of 
finding a little twig in a shell “partly petrified” (i. e., pearl-coated?), and in an Iowa 
paper, where the writer refers to finding grains of sand and gravel partially coated 
with pearl nacre. One paper affirms that they were “originally created” with the 
mollusk, and bases this opinion on the fact that large pearls are found in small shells, at 
least sometimes. One paper (Indiana) which advocates the theory of injury refers 
to the fact that the pearl-bearing bed is close to a steamboat-landing, and considers 
the frequent disturbance of the water as a favorable condition. It is apparent, 
however, that this fact might operate quite as effectively in behalf of the intrusion 
theory. 
Question 13, as to the position in which pearls are most frequently found in the 
body of the mussel, is answered by a very large proportion of the responses, and with 
a good deal of variety, though the general results are pretty clear. A difficulty con- 
spicuous in these answers is the lack of definiteness in the terms employed to denote 
the parts of the shell and the body — the words varying much in the use of different 
individuals and affording a striking illustration of the value of exact scientific terms 
as compared with ordinary phraseology. Notwithstanding this fact, however, it is 
not hard to ascertain what is meant by most of the writers, and indeed many have 
expressed themselves very clearly, and only in a few cases is the real meaning 
obscure. 
To this question 112 answers have been received; several uncertain or indefinite — 
some merely saying that the pearls are found between the mantle and the shell, or 
similar expressions of an indeterminate character; 16 refer to them as occurring in or 
near the hinge, but most of these also state that such pearls are rarely valuable 
or well-formed, being generally “slugs”; 44 specify the borders of the mantle as the 
chief location for free and valuable pearls, in or near the edge, some saying between 
the mantle and the shell, others implying a position (obscurely expressed) between 
the mantle and the gills ; 39 state that the pearls are chiefly found at the posterior 
end of the shell (“thin end,” “sharp end,” “small end,” “ tail end,” “point,” etc.), 
either “in” or “under” the mantle, or between it and the shell, as before. Four 
give little sketches to illustrate this statement (Kansas, Tennessee, and Wisconsin). 
Several refer to them as occasionally found in various other parts of the body, “in the 
meat,” etc. Three papers (Indiana and Tennessee) speak of them as covered with 
or “incased in” a soft transparent substance; and two refer to pearls as sometimes 
imbedded in the shell (Wisconsin) or growing so as to “form a socket” in it (Iowa); 
this fact is well known, though of rare occurrence. 
