A^IIl] 



THE ORIGIN OF PEARLS 



93 



Since this little book is written for those who are 

 not likely to consult a long series of original works, 

 the author may be pardoned for giving yet another 

 similar compilation. 



Author 

 Aelian 



Eondeletius (1554) 

 Eedi (1671) 



Various 16th cent, writers 

 Reaumur (1717) 

 Home (1826) 



Filippi (1852) 

 Kiichenmeister, \ 

 Yon Hessling, 



and Meckel j 

 Moebius (1857) 

 Kelaart (1857-59) 

 Garner (1863) 

 Comba (1898) 

 Dubois (1901, 1903) 

 Jameson (1902) 

 Herdmanand|^^^2_Qg. 



Hornell i 

 Seurat (1902) 

 Giard (1903) 

 Boutan (1904) 

 Rubbel (1911) 

 Jameson (1912) 



Theory of cause 

 Flashes of Lightning. 

 Parasites and concretions. 

 Grains of sand. 

 Eggs of the mollusc. 

 Solidification of shell forming fluid. 

 A modified view of the egg theory- 

 abortive ova. 

 A worm parasite, Distomum. 



(1856) Parasites, sand, eggs. 



Entozoa. 



Sand, diatoms, eggs and parasites. 



Distomum parasite. 



Parasites. 



Parasites. 



Parasites. 



Parasites, etc. 



Parasites. 

 Parasites. 

 Parasites. 

 Shell substance 



Shell repair substance and perhaps 

 parasites. 



It will perhaps be startling even to scientists, who 

 have not read up the older biological literature, to 



