122 FISHERIES OF THE UNITED STATES. [16] 



izer for crops. It forms an excellent bait for eels, and is fed to them 

 regularly when kept in confinement. In Southern New Jersey and 

 Delaware, there are several factories for the grinding of King Crabs 

 for fertilizing purposes, and there and elsewhere the farmers also pre- 

 pare them for their own use. They are captured during May and 

 June, when the females, accompanied by the males, ascend the beaches, 

 in immense numbers, to spawn. They are picked up in the hands or 

 with pitchforks, deposited in large piles to dry for one or two months, 

 and then broken up and ground. The product is termed concerine, 

 and is used alone or composted with muck, lime, &c. It is extensively 

 employed by the fruit-growers of New Jersey, Delaware, and Maryland, 

 and is also applied to general crops. 



WORMS. 



Several species of marine annelids are occasionally employed by fish- 

 ermen as bait, but mainly by amateurs. These animals give rise to no 

 industry, but are generally obtained by those who desire them for their 

 own purposes. The commoner shore species are the ones employed, 

 and include, among others, Arenicola marina, the several species ol 

 Nereis, Diopatra cuprea, Glymenella torquata, &c. The common Earth 

 Worm (Lumbricus terrestris, L.) is also occasionally used as bait in the 

 fresh waters. Some of the Western Indian tribes use a species of fresh- 

 water annelid (Ephydra Sp.) as food. It is prepared dry for keeping. 



Medicinal Leech. — The American medicinal Leech (Macrobdella 

 decora) is quite widely distributed through the Northeastern part of the 

 United States, ami was formerly extensively employed by physicians. 

 In recent times, the practice of leeching has greatly declined. Prior 

 to 1839, there was no regular importation of foreign Leeches into this 

 country, and physicians were obliged to depend almost entirely on 

 the American species, which, for most purposes, is inferior to the 

 European, having less power of attaching itself. This very weakness, 

 however, renders it preferable for many cases, where it is desirable to 

 distribute the blood-letting over a greater surface than would be acted 

 upon by a single European Leech. In 1839, the first importing house 

 for European Leeches was established in New York, and from that time 

 until about 1856 the sale of Leeches rapidly increased, over 800,000, 

 valued at $90 per thousand, having been imported the latter year. 

 Since 1856, the use of Leeches, and, as a consequence, the quantity im- 

 ported, has gradually diminished from year to year, until, in 1880, the 

 import trade was only one-seventh in value that of the former year. 

 The prices have also declined to from $25 to $50 per one thousand, ac- 

 cording to quality. While the American Leech has been collected for 

 medicinal purposes in various localities where it occurs, the main 

 source of supply has always been the eastern j>artof Pennsylvania, and 

 especially Bucks and Berks counties. Between 1840 and 1850, more 



