77 



which had been relaid near Fleetwood. The colour 

 manifests itself in patches and streaks of pale green on 

 the mantle, in engorgements of the blood vessels and in 

 masses of green coloured leucocytes in the heart. The 

 leucocytes are apparently all amoeboid wandering cells, 

 comparable to the colourless corpuscles of the blood of 

 higher animals, and the colouration coincides with their 

 distribution. 



' The six greenest and six whitest of 120 of these Oysters 

 were chosen for analysis ; also a quantity of the greenest 

 portions of the greenest Oysters was selected from another 

 batch, and compared with the corresponding portions of 

 the whitest Oysters. The iron was not determined in the 

 latter comparison, owing to contamination of metal in 

 cutting. 



' The following were the results obtained : — 



' The excessive quantity of copper in the selected green 

 Oysters is 3"75 times that in the white calculated per 

 Oyster, and 3'03 times calculated on the ash. In the 

 selected parts the total copper present calculated on the 

 ash is high in both cases, and the green parts again show 

 a marked excess in the proportion of 2" 1 to 1. The copper 

 and iron in the white specimens are about normal, but 

 the increased quantity of iron in the green is marked, 

 being 2*5 times that of the former. Still there is relatively 



