92 
BULLETIN OP THE UNITED STATES FISH COMMISSION. 
oesophagus. According to Mayer, whom Roesel quotes with some reserve, it was the 
custom of the inhabitants of Asiatic Tartary and Ukrania to collect crayfish at the 
time of the year in which they were in the best condition and place them in large pits 
in the ground. Here they were broken up and allowed to remain all winter, during 
which time the evil odor kept everybody away. In the spring the owners would 
return, wash out the remnauts of the crayfish in water, and sift out the stones with a 
sieve which they used for this purpose. It was formerly the custom also in Poland 
and Russia, on the River Don, to collect crayfish in large quantities and allow them 
to rot in the fields or in pits. The stones were afterwards carefully collected and sent 
to market to be used as medicine. 
Mr. Baker ( 7 ) communicated to the Royal Society on February 25, 1748, an inter- 
esting letter on “ crabs’ eyes” from Dr. James Mounsey, a Russian physician. He 
noticed the seal-shaped spots on the wall of the stomach, which mark the position of 
the developing gastroliths, and concluded that the latter helped to form the new shell, 
which, he says, “ does not greatly recommend the opinion that these stones have a 
dissolving quality of service against the stone in the human kidneys and bladder.” 
“The price comes to a groat or sixpence a pound. All the apothecary shops through- 
out the whole Russian Empire are furnished with them, and great quantities are 
exported.” Notwithstanding their cheapness, “fictitious bodies, made of chalk” and 
“ tobacco-pipe clay ” were cast in molds and substituted for real “ crabs’ eyes.” In 
this case the counterfeit undoubtedly possessed all the virtues of the genuine article. 
K. E. von Baer ( 6 ) thought that the gastroliths were salivary stones, developed 
in the lumen of a salivary gland, an idea which was not destined to bear much fruit. 
Some writers even pretended that they were cast out through a fissure in the walls of 
the stomach and body. 
Van der Hoeven { 195 ) seems to have been one of the first in the present century 
to protest against the theory that the sole function of the gastroliths was to provide 
lime for the new shell. In his Handbook of Zoology, a translation of which was 
published in 1834, he says : 
The part, however, which the crabs’ eyes take in the secretion [of the hard shell] can not be 
great when we compare their weight with that of the calcareous matter of the shell. During the 
time that the shell is still increasing in hardness no new crabs’ eyes are produced; but only after 
the shell has attained its greatest hardness is calcareous matter again secreted on the walls of the 
stomach, and new crabs’ eyes again appear. Thus the production of crabs’ eyes would seem to be 
a vicarious secretion of such constituents of the blood as, if too abundant, would be injurious to the 
organs, like the secretion of urine for instance, but with this difference, that the calcareous matter is 
not set at liberty shortly after its secretion, but remains accumulated for a long time in continuance. 
Max Braun, in his work on the molting of the crayfish ( 22 ), concluded that the 
gastroliths were cuticular products analogous to the integument, but paid no attention 
to their function or growth. 
Vitzou { 197 ) says that shortly after the molt in the lobster the gastroliths are dis- 
solved in the acids of the stomach and, entering the lymph, form an inorganic reserve 
comparable to the phosphatic plaques which are found in the membranes of the foetus 
in ruminants. 
The problem of the gastroliths has recently been attacked by Irvine and Wood- 
head { 105 ) in one of their valuable communications on the secretion of carbonate of 
lime in animals. They conclude that, if the gastroliths play any part at all, they must 
be converted into phosphates and thus carried in the lymph. If the brachyura have 
