CRAYFISHES AND PIGS. 45 
collected in vast numbers, and sold for medicinal 
purposes as a remedy against the stone, among other 
diseases. Their real utility, inasmuch as they consist 
almost entirely of carbonate of lime, with a little phos- 
phate of lime and animal matter, is much the same as 
that of chalk, or carbonate of magnesia. It was, for- 
merly, a current belief that crayfishes grow poor at the 
time of new moon, and fat at that of full moon; and, 
perhaps, there may be some foundation for the notion, 
considering the nocturnal habits of the animals. Van 
Helmont, a great dealer in wonders, is responsible for 
the story that, in Brandenburg, where there is a great 
abundance of crayfishes, the dealers were obliged to 
transport them to market by night, lest a pig should 
run under the cart. For if such a misfortune should 
happen, every crayfish would be found dead in the 
morning: “ Tam exitialis est porcus cancro.” Another 
author improves the story, by declaring that the steam 
of a pig-stye, or of a herd of swine, is instantaneously 
fatal to crayfish. On the other hand, the smell of 
putrifying crayfish, which is undoubtedly of the strongest, 
was said to drive even moles out of their burrows. 
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