Cell Structure, Growth and Division in the Antheridia of Polytrichum etc. 167 
of the cell, the concept has gained wide acceptance as including the sub- 
stance of the spindle fibers, astral rays and other fibrous cytoplasmic 
structures; of blepharoplasts, centrospheres and similar masses of active 
substance; of plasma membranes; of vacuolar membranes, at least in some 
cases like the sporanges of certain mucorineae (Harper, 1899; D. B. 
Swingle, 1903); and in all probability of nuclear membranes as well. 
The name kinoplasm has the advantage of a purely physiological 
connotation; it implies nothing as to the morphological, or even the Chem- 
ical, identity of the structures to which it is applied. Indeed, it can hardly 
be doubted that kinoplasm is, at different times and in different places, 
of varied Chemical composition; although its tendency to take on certain 
forms — appearing, in an active state, particularly as fibers — its relation 
to processes which involve especial expenditures of energy, and its behavior 
toward stains, suggest some degree of Chemical, and, at least in many 
cases, of morphological relationship between its various manifestations. 
While, therefore, we may expect that a more intimate knowledge of the 
chemistry of the cell and of its ontogeny and phylogeny will in time neces- 
sitate a more intricate terminology for the cell constituents, the generalized 
couception of kinoplasm is for the present extremely helpful. 
Kinoplasmic structures are not necessarily permanent, nor even long- 
persistent. Not only may kinoplasm, though retaining a genetic continuity, 
take on very different forms at different times — as when the material 
of the spindle fibers is transformed into plasma membranes — but the 
amount of substance within the cell which is recognizable as kino- 
plasm varies greatly; being, for example, most abundant at the time of 
nuclear and cell division, and least abundant during the so-called resting 
period. The plasma membrane, to be sure, is an example of a long-per- 
sistent kinoplasmic structure; in the pollen mother cells of Larix (Allen, 
1903), a kinoplasmic network is recognizable in the cytoplasm for several 
months at least; and Gregoire and Berghs (1904) find likewise a per- 
sistent cytoplasmic reticulum in the germinating spores of Pellia. Sim- 
ilarly, if nucleoles are, as Strasburger has long contended, temporary 
reserves of kinoplasm which becomes active in mitosis, an explanation is 
at hand for the apparent periodic increase and decrease in amount of this 
substance. But however long-continued the existence of particular kino- 
plasmic structures may be, the total bulk of kinoplasm must be increased 
from time to time at the expense of other cell constituents, not only to 
keep pace with the growth of the living matter as a whole and to replace 
the losses from ordinary catabolic processes, but also because this especial 
substance must be subject at times to particularly rapid loss by virtue 
