411 



gilt, but refusing to admit English work or thought as of 

 the same value at all — should refer to the germinal vesicle 

 as though it were an accepted fact that it dies upon impreg- 

 nation : " In the eggj on impregnation, it seems to me 

 natural (I say it "with a smile) that the old sun that ruled it 

 should go down, and that a new sun, stronger in the com- 

 bination of the new and the old, should ascend into its 

 place" (p. 33). Had Mr. Stirling never studied the works of 

 Ley dig, Mecznikow, and others, he yet might have found in 

 Professor Huxley's paper on Pyrosoma facts entirely dis- 

 cordant with his view of the case. But error is to be 

 expected when bibliographical knowledge only is brought 

 to bear on such a question as the signification of Protoplasm, 

 and the authority of Professor Strieker is quoted as conclusive 

 against that of Professor Huxley. 



Dr. Van Beneden does not, however, entirely clear up 

 this question of the disappearance in some eggs and the im- 

 portant cleavage-function in others of the germinal vesicle. 

 We wish Dr. Van Beneden had found it Avithin the scope of 

 his work to look at the vegetal ovum, with a view to solv- 

 ing this difficulty. If we may believe the observations of 

 some high authorities (Tulasne) the mass which is fertilized 

 in phsenogamous plants at any rate, that which corresponds 

 to the cell-egg in animals, is a simple mass of protoplasm 

 with nothing corresponding to germinal vesicle and spot, — no 

 nucleus and nucleolus. Immediately upon fertilisation, cells 

 are produced in this mass by free-cell-formation, which divid- 

 ing, give rise to the embryo. But if the observations of Henfrey 

 are to be accepted, the embryo-sac does develop one or more 

 germinal vesicles before ever the pollen-tube touches it, 

 though there is no enclosure by cellulose until after that time. 

 In this case, the embryo-sac with its protoplasm corresponds 

 to the primitive protoplasm of the young ovary of animals, 

 in which germinal vesicles arise, just the same in the plant 

 as in the animal. In the plant, however, the jirotoplasm 

 never segregates nor is it removed from the seat of its growth. 

 There are some entomostraca (see the recent work of M. 

 Miiller on the Scandinavian Cladocera) in which four 

 germinal vesicles are enclosed in one mass of protoplasm ; only 

 one of these vesicles develops and forms an embryo, the 

 other being absorbed before fertilisation. So with the 

 embryo-sac of Orchis for instance, three or four germinal 

 vesicles arise in the mass of protoplasm, but only one develops, 

 and the others are absorbed, forming an internal albumen in 

 some cases ; the absorption is here, however, after fertilisa- 

 tion. Dr. Van Beneden would no doubt speak of the 



