OF CONCHOLOGY. 135 



it, SO transfixed, in vinegar. In a few seconds the parts of the 

 needle in contact with the flesh will become covered with a coat- 

 ing of red copper reduced to the metallic state. It appears 

 that an oyster in Avhich the green tint is peculiarly clear is 

 especially to be avoided, while those which are of a bluish green 

 color are not only fit to eat, but are considered very choice. 



Now, the green tint frequently observable in the oyster has 

 attracted the attention of scientific men from time to time, long 

 before the serious occurrences just mentioned, which took place 

 in the spring of 1862 ; and it Avould seem that, in nearly all the 

 cases on record in which fatal consequences have followed their 

 use as an article of food, there is reason to suspect that copper 

 has been the chief cause of the evil. 



So far back as the year 1713, mention is made of a certain 

 luxurious supper, given by an ambassador at the Hague, who, in 

 order that no delicacies might be wanting, procured green 

 oysters from England. All who ate of them are said to have 

 been immediately seized with severe colics, and to have been 

 cured with great difliculty. Lentilius, on whose authority this 

 account rests, states that it was afterwards ascertained that the 

 merchant, whom he anathematizes with his whole race, had 

 palmed upon the ambassador some common oysters, tinted wJth 

 copper, for the true greens.* 



Another case is recorded by Dr. Chisholm in the "Edinburgh 

 Medical and Surgical Journal," Vol. IV., p. 400. He was 

 informed by Mr. William Newton, of St. Croix, that some time 

 after the British frigate " Santa Monica " was cast away on the 

 coast of the Island of St. John, (one of the Virgin Islands,) 

 oysters grew on her bottom, which was coppered. Many people 

 ate of those oysters, and, although the consequence was in no 

 case fatal, it was dangerous, and unpleasant in a very great 

 degree, producing cholera and excruciating torment. 



With regard to those oysters in which the green tint is not 

 due to any such deleterious cause, but, on the contrary, rather 

 enhances their value as a delicacy, many very difi'erent explana- 

 tions have been ofi'ered of the manner in which that color is 

 acquired. It has been said that the water in the artificial beds, 

 remaining stagnant in warm weather, becomes green, and soon 

 communicates the same color to the oysters themselves ; and Dr. 

 Johnston, speaking of the French 03^sters, says that, in order to 

 communicate to them a green color, which, as with us, enhances 

 their value in the market and in the estimation of the epicure, 

 they are placed for a time in tanks or " parks," formed in par- 



* Dr. Johnston's " Introduction to Conchology," p. 19. 



