THE STRUCTURE AND DIVISION OF THE VEGETABLE CELL. 21 



nuclei, thus forming a group of four at either end. Up till this time 

 the protoplasm has remained entire; but now one nucleus at either 

 end draws itself away from the remaining three, when, between 

 each of the latter, a division of the protoplasm takes place, and 

 the protoplasm surrounding each nucleus contracts, and assumes 

 an individuality which it did not before possess. One of these 

 little masses at the upper end is the egg-cell, the other two the 

 Synergidce, while the three at the lower end form the antipodal 

 cells. Now each and all of these are, and remain till fertilization, 

 naked, nucleated protoplasmic masses, and one at least of them the 

 most important cell that the plant can produce. Another example 

 may be mentioned in which not only is a cell, but many, without 

 walls, and forming a developed tissue, viz., the tissue in the 

 sporangium of Equisetum, from which the spore-mother cells are 

 produced. The same holds good of the spore-mother cells 

 themselves, and it is not till after the final division has taken place 

 that any cellulose is deposited on their surface. In fact, were the 

 definition of the triple structure rigidly applied, not only would a 

 few but most of the egg-cells of all plants be excluded, and also 

 many of the spores of both the higher and the lower Alga?. 



In the year 1845 the comparative unimportance of the cell-wall 

 was pointed out by Nageli, and this conclusion was soon adopted 

 and emphasized by others, especially by Max Schultze, who 

 observing, as has just been shown, that many of the most im- 

 portant cells were destitute of a membrane, defined a cell as " a 

 little mass of protoplasm, inside of which lies a nucleus." This 

 definition did not, however, include all the vegetable proto- 

 plasmic structures either with or without a cell-wall, for many had 

 been observed in which no nucleus could be seen. Examples 

 of such are to be found in the Antherozoids of the Cryptogamia, 

 and at that time most, if not all the Fungi, were regarded as 

 being without a nucleus, in addition to many other Thallophytes. 

 For such elementary structures Hackel, in 1866, proposed the 

 name of Cytode. We have, then, this distinction : A cell is a 

 "little mass of protoplasm, inside which lies a nucleus ;" while 

 a cytode is " a little mass of protoplasm without a nucleus." 

 This appears to rather complicate matters, as instead of having 

 only one morphological element, we have, so far as terminology at 

 least is concerned, two, the cell and the cytode. The latter term 

 may, however, eventually have to be abandoned, at least with 



