232 RAMBLES OF A NATURALIST. 



The Hermellas of Guettary and the Teredos of 

 Saint Sebastian were admirably adapted for experi- 

 ments on artificial fecundation. All that was neces- 

 sary to secure a supply of thirty or forty thousand 

 eggs was to open one male and four or five females 

 in a vessel filled with sea-water. This accouchement 

 forcA in no way interfered with the success of the 

 experiment. In a few moments vital activity began 

 to manifest itself, and in the course of fifteen or 

 eighteen hours every ovum had become an active 

 larva, which swam about in all directions. By the 

 aid of the microscope I frequently examined the 

 succession of phenomena which brought about 

 this marvellous result, and while my eyes were fol- 

 lowing the slightest appreciable modifications, and 

 my hands were engaged in tracing the drawings 

 which were intended to represent what I saw, my 

 mind was busily engaged in considering all the great 

 questions of natural philosophy, which are suggested 

 by the study of embryology. It would be alike dif- 

 ficult and out of place were we to enter upon 

 the consideration of all the problems which have 

 been advanced or solved by this study. We will 

 here merely consider those which precede the first 

 rudiments of the nascent organisation. Let us 

 enquire whence comes the germ of the new being ? 

 what are the general laws which preside over its de- 

 velopment ? what is the probable part played by the 

 two elements, which almost always intervene to 



suffice to destroy all the organic corpuscles contained in more than 

 twenty thousand cubic yards of water ; but it is probable that this 

 proportion would require to be augmented. 



