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R. A. HARPER 
exist. Such secondary interior phases doubtless exist in the case of the 
granular precipitates in vacuoles and the frequently observed inclusions in 
the nucleoli. They also provide for the development of filar and reticulated 
structures in colloidal systems in which the general consistency is still 
quite fluid. What appears perhaps most inadequate in the data of col- 
loidal chemistry as a basis for the conceptions developed from a study of 
the cell itself is the failure of students of unorganized colloids to emphasize 
the evidence for the existence of the thready reticulated and filar structures 
which are so familiar to the cytologist in fixed material. 
Boresch has also described filar structures in the living protoplasm of 
moss cells whose method of occurrence, sensitiveness to environment, 
reagents, etc., suggest their resemblance to the reticulated chains of granules 
produced by Hardy. As Lundegardh has pointed out, these figures of 
Boresch show many resemblances to the so-called myelin structures and 
are doubtless in some cases the same cell elements which have been variously 
described as mitochondria, Chondriokonten, etc. They are far less thread- 
like than the highly differentiated, clean-cut fibers of the asters, spindles, 
etc., of our fixed preparations, but are interesting as showing that thready 
structures as well as granules, foams, emulsions, etc., are to be reckoned 
with as constituents of protoplasm. These fibers of Boresch, as also the 
mitochondria, show no polar orientation except perhaps as they are more or 
less passively iiifluenced by the karyokinetic figures in dividing cells. Their 
form cannot hence be a:scribed to the operation of fields of force, magnetic 
polarities, etc., operating on the cell substances, as is so frequently claimed 
for the fibers of the karyokinetic figures. 
To provide an adequate basis for understanding the observed facts of 
polarity, however, it seems to me that the conception of compound aggre- 
gate polyphase systems is more suggestive than these attempted analogies 
between the magnetic poles and their fields of force and the karyokinetic 
figures. The suspension of one or several polyphase systems within another 
polyphase system is entirely harmonious with what we know of the high 
viscosity of many of the constituents of protoplasm. In the spatial arrange- 
ment and interrelations of these systems polar differences of ihe most 
diversified types are bound to arise in the mass as a whole and express 
themselves in the form and relative rigidity and surface tension of different 
parts, as well as in the interrelations between the cells of a group in contact. 
But the most important factor which the cytologist must recognize 
with reference to the development of such systems as are shown in the 
organization of the cell is the time element. In contrast with any known 
unorganized system, the cell propagates itself by division, as Weismann has 
so adequately and fully emphasized. This means that the protoplasmic 
structure is not formed de novo in reproduction, but has perpetuated itself 
as such from the remote geologic periods when life first appeared upon the 
earth. The spatial interrelations of the colloidal elements and systems of 
