ON THE LIFE CONDITIONS OF THE OYSTER. 569 



The increased quantity of iron present may also be due to abnormal 

 conditions of life, but a more accurate localisation of the normal iron 

 of the oyster is necessary before this can be decided. 



This green leucocytosis has been obsei'ved by Herdman and Boyce in 

 other oysters, including those of Falmouth, and it is likely to be the real 

 cause of their colour ; a colour therefore due to copper as previously sup- 

 posed, but accompanied by a diseased condition. Whether the presence of 

 copper in the water facilitates in any way the development of the disease 

 has not been determined ; experiments made on keeping oysters in very 

 dilute saline copper solutions give no affirmative results beyond a certain 

 amount of post-mortem green staining. 



Manganese was found to be present in several of the varieties of oysters 

 analysed. Its detection is readily effected in the electrolytic method of 

 analysis as it separates at the anode as peroxide. Colne oysters contained 

 0-14 mgrme. per oyster — a rather smaller quantity than the iron found. 



Note added by Mr. G. C. Bourne in September 1898. 



In 1890 I examined a large number of green Falmouth oysters, all cf 

 which exhibited the green leucocytosis subsequently described by Professor 

 Herdman. I repeatedly tested the masses of pale-green amoeboid cells 

 taken from the gills for copper, but I failed to convince myself of its pre- 

 sence, though I once or twice got indications of the characteristic reactions. 



On the other hand, I found large numbers of desmids in the alimentary 

 tract, and was inclined to attribute the ' greening ' to their presence. 

 Having left Plymouth whilst my investigations were in progress I was 

 unable to continue them, but I can confirm all that Professor Herdman 

 states on the subject of green leucocytosis. 



Bird Migration in Gh-eat Britain and Ireland. — Interim Report of the 

 Committee., consisting of Professor Newton {Chairman')., Mr. John 

 CoRDEAUX (Secretary), Mr. John A. Harvie-Brown, Mr. E. M. 

 Barrington, Rev. E. Ponsonby Knubley, and Dr. H. O. Forbes, 

 appointed to tvorh out the details of the Observations of the Migra- 

 tion of Birds at Lighthouses and Lightships, 1880-87. 



Your Committee have much pleasure in reporting that Mr. William Eagle 

 Clarke, since his recovery from his serious illness in 1897, has been able 

 to make very considerable progress in extension of his very admirable 

 report read at Liverpool in 1896. 



His work in 1898 has consisted in collecting all the serial literature 

 and the Transactions of Societies in evidence since the commencement of 

 the inquiry in 1880, for the purpose of supplementing the data relating to 

 species, and he has succeeded in adding ten thousand records of great value 

 to the Lighthouse data. 



It is further his intention this autumn to commence, from the collected 

 material in notes and the schedules, a history of each species in connec- 

 tion with its migration, and to give statistics concerning the dates of 

 arrival and departure, and the routes followed. 



To work out these details in a satisfactoi-y manner will occupy two or 



