SEA-FISHERIES LABORATORY. 177 



very properly replies a few days later* that this fact is quite 

 in accord with general principles, and was previously 

 known. M. Boutan in a letter (20th Jan., 1904) informs 

 me that he is on the point of departure for the East in 

 order to investigate the matter further. 



Notwithstanding this recent activity, especially amongst 

 our French neighbours, there is still a good deal of work to 

 be done before the whole process of pearl formation can be 

 considered as cleared up. We want to know especially : — 

 1st, The exact details of formation of the pearl-producing 

 epithelial sac when deeply placed in the tissues, and 2nd, 

 the complete life-history of the parasite inside the sac. 



* Comptes rendus, Soc. Biol., Paris, 19th Dec, 1903, p. 1618. 



