446 Ferguson . — The Development of the Egg and 
the nucleus a vacuole filled with a nuclear sap capable of 
taking up or elaborating this material. Ikeno (’98) found 
a similar substance in the sexual nuclei in Cycas, and Arnoldi 
(’ 00 ) in Cepkalotaxus. Blackman (’98) devoted several para- 
graphs to a discussion of metaplasm, as it manifested itself 
in the egg-nucleus of Pinus sylvestris. He found that it was 
present in the young nucleus in the form of granules, but 
that it later united with the chromatin to form the nuclear 
reticulum. Chamberlain (’99) does not recognize the pre- 
sence of this substance in the egg-nucleus in Pinus Laricio ; 
and there is no evidence of its existence in the sexual nuclei 
of the species of Pines studied by myself. 
According to Wilson ( 99), c protoplasmic substances repre- 
sent the active, metaplasmic structures the passive elements ’ 
of the cell. During the development of the egg-nucleus in 
the species of Pines which have formed the basis of these 
studies, there is never any deposit within the normal nucleus 
of a granular substance; but the linin, as already stated, 
becomes very abundant. Just what proportion of it is active 
in cell-division we are unable to say. Without doubt a large 
part of the linin merges into the cytoplasmic network during 
the first segmentation of the oosphere-nucleus, but even so 
it cannot be classified with the passive elements of the cell. 
Blackman (’98) wrote : c The stage in which the nucleus is 
found in a position between the apex and the centre of the 
egg is rarely met with’ ; and Chamberlain (’99) stated ‘that 
in over three hundred preparations, less than a dozen * show 
early stages in the development of the egg-nucleus. During 
the course of these investigations upon the Pines, more than 
twenty-five hundred preparations, representing several thousand 
archegonia, have been studied, and no developmental stage has 
been more frequently met with than that by which the nucleus 
assumes its central position in the egg. Such an appearance 
as that illustrated by Chamberlain in his Figs. 18 and 19 
has often been observed in both the young and the mature 
egg-nucleus, in the conjugating nuclei, and also in the various 
nuclei of the proembryo. They have been wholly disregarded 
