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 entu-ely 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 : " Tarn 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. 



