20-2 



fouTirl copper stored up in greatly iucreasefl quantity in 

 the niimerons leucocytes which characterise this diseased 

 condition; so that prohahly these "copper" oysters even 

 cannot be trusted to tree themselves from pathogenic 

 organisms througli the action of their own copper. 



In dealing with siich a case as that of the oystci', 

 liowcvev, it must he noted that there are two further 

 cDiidii ions whi(di may etfect the successful applicatioji of 

 ilic ahovc-mentioned methods. In the first place lliu 

 patliogenic organisms arc not necessarily free in ilie 

 water, hut may he in or upoii the living tissues of the 

 mollusc so as, possibly, to be protected from the toxic 

 action of the copper. Secondly, the washing of the living 

 oyster must be carried on in sea-water : there is 

 ap])arently a difference in some of tli(> experiments 

 between distilled water and tap-Avatei', and what further 

 complications may be introduced by tlie salts in the 

 medium surroiniding the oyster has still ii> be determined. 

 In c<()i juuction with Professor ]}. Moore, of the Dejnui- 

 ment of Jiiocliemistry, we propose to inv(>stigate ilic whole 

 (|uesti:)n of this oligodynamic action of coppc]- and other 

 metals upon the oi'ganisms iji shell-fish with sp(>cial 

 reference to ovster culture. 



