206 Farmer and Digby.—On the Cytological Features exhibited by 
this elimination of chromatic substance is to be regarded as always possessed 
of the same significance seems to us to be doubtful, but the facts before us 
are not as yet sufficient to enable us to usefully discuss the question at the 
present time. It may well be that we are here dealing with matters 
destined to throw light on the bodies known as chromidia, but overmuch 
speculation in proportion to the amount of positive knowledge has already 
grown up around these matters, and it seems premature to add to it on 
this occasion. 
General Conclusions. 
The main points of general interest which appear to us to emerge from 
the study of the ferns as detailed in the foregoing account relate to the 
formation of the spindle and to the behaviour of the chromosomes in 
the sports and hybrid respectively. 
The mode of differentiation of the kinoplasmic weft around the nucleus 
supports the view long ago advanced by one of us to the effect that this is to be 
regarded rather as a specialized and temporary arrangement in the cytoplasm 
than as indicating a permanent substance in the cell. Strasburger, to whom 
we are indebted for the clear recognition of the differentiation in question, 
also now holds that no absolute distinction between kinoplasm and the 
cytoplasm can be maintained, although so long as it does exist the proto¬ 
plasm, thus distinguishable, is the seat of metabolic change of a nature often 
very definite in character. 
The spindle fibres are clearly produced at the expense of such cyto¬ 
plasm in the cases studied here, and indeed more clearly so than is 
frequently the case in other plants. We think that the particular mode 
of the formation of the spindle points strongly in the direction of its 
originating as the result of electrical disturbance within the colloids of which 
the cytoplasm is made up. We have shown how it arises just above the 
aggregations of chromatin-containing linin, and we believe that a real causal 
relation is here indicated. It will be remembered that one of the characters 
of albumin is its capacity of absorbing, or otherwise associating with itself, 
dissociation products which may carry electrical charges of different sign. 1 
The apparent magnitude of the observed results is to be attributed, at least 
in part, to the smallness of the field (the cell) in which the forces are operating. 
The view that the spindle owes its existence as well as its character to 
electrical conditions has been repeatedly advocated. In recent years 
Hartog 2 has endeavoured,by working models of an ingenious form, to show 
that the poles of the spindle may be compared with unlike poles of a magnet, 
and that the curved system of lines assumed by the achromatic fibrils are to 
1 See Lillie, R., On the differences in the electrical connexion of certain free cells and nuclei. 
Am. Journ. of Physiol., viii. 
2 Hartog, M., The dual force of the dividing cell. Proc. Roy. Soc., B. 76. 
