138 AMERICAN JOURNAL 



scope, and compared the orifices of the tubular filaments with 

 the size of the animalcules, that the latter could not possibly 

 enter the system of the oyster in that region. 



Perhaps one of the most significant facts recorded by M. 

 Gaillon, as the result of his laborious observations, is that, at 

 different seasons of the year, the water of the oyster "park " 

 , presents very different tints, being sometimes brown, at others 

 green or yellow, both the brown and the yellow being equally 

 the result of the abundant presence of microscopical animalcules 

 of a different species from the green Vibrio ostrearius. The 

 brown species, we are told, has as striking an effect on the color 

 of the oyster as the green one, and greatly improves its flavor ; 

 whereas the yellow are considered prejudicial. 



With reference to these so-called animalcules, we need scarcely 

 state that the atoms hitherto referred to the genus Vibrio are 

 now recognized as being of a vegetable nature. The species 

 08t7'earius appears in the last edition of Pritchard's work on 

 the Infusoria as a Navieula. 



In spite of the detailed observations and experiments of M. 

 Gaillon, we find M. Valenciennes remarking, at the commence- 

 ment of a paper on the same subject in the " Comptes Rendus 

 de I'Academie des Sciences " for 1841 : " On sait combien les 

 explications donndes jusqu' a ce jour sur la coloration des huitres 

 laissent encore a desirer." The object of this paper is to prove 

 that the green color is due to an animal matter which must be 

 quite distinct from all green organic substances hitherto known. 



M. Valenciennes says that the only externally visible organs 

 which display this color are the four leaflets of the branchiae. 

 On lifting the upper part of the mantle, the inner surface of the 

 labial palps alone appear colored ; and on extending the ex- 

 amination to the internal organs, the intestinal canal beyond 

 the stomach is seen to be of a bright green color. The liver is 

 of a blackish green tint instead of the usual red ; but neither 

 the muscles, heart, nor even the juices of the body exhibit any 

 change of color. 



According to M. Valenciennes, the coloring matter offers no- 

 thing remarkable when viewed under the microscope ; but when 

 examined chemically it is found to possess certain properties 

 which led him to the conclusion above quoted. His observations 

 were made on the large green oysters of 3Iarennes ; but he says 

 that like results have followed the application of the same chemi- 

 cal tests to the so-called green oysters of Ostend, which are less 

 strongly colored. 



M. Dumas made some experiments in order to discover if the 

 green matter might not owe much of its color to Prussian blue 



