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by Agardh. He further remarks, that his paper of 1842 contains a 

 record of other observations made in a field beyond the region of 

 Agardh's researches ; observations which he thinks explain how it is 

 that fibre forms the membrane of the cell, and, what he deems of 

 more importance still, the mode of origin of fibre. He refers gene- 

 rally to the drawings in that paper, from which, in connection with 

 facts previously recorded in the Philosophical Transactions, he states 

 that it appears — 1, that fibre has its origin in the so-called " cyto- 

 blast," the outer part of which always passes into a ring or coil of 

 fibre ; 2, that when a cell is to arise, its primary membrane is formed 

 out of this ring or coil of fibre ; 3, that then the nucleolus of the 

 " cytoblast " becomes the nucleus of the cell; 4, that the outer 

 part of the nucleus of the cell also passes into a ring or coil of fibre, 

 wherewith to form deposits such as the annular and spiral, or to 

 weave the secondary membranes; 5, that the term "cytoblast" is 

 unsuitable, as the body so called does not always become a cell ; 

 6, that fibre is thus more universal as well as more primitive even 

 than the cell, for fibre not only forms the cell, but it forms other 

 structures without having first to form a cell ; 7, that the prime 

 mover in both the "cytoblast" and the nucleus is the nucleolus, 

 which is the organ of absorption, assimilation, and secretion; 8, 

 that the nucleolus is continually giving off its substance and con- 

 tinually renewing it, continually passing from the state of nucleolus 

 into that of " cytoblast" or nucleus, — so that the " cytoblast " and 

 the nucleus are each of them but the nucleolus enlarged ; 9, that it 

 is therefore the nucleolus enlarged that passes into fibre; 10, that 

 the nucleolus always passes into fibre, and directly into no other 

 form than that of fibre ; 11, that thus the whole organism arises 

 out of nucleoli, for fibre is but the nucleolus in another shape, and 

 every structure arises out of fibre ; 12, that the nucleolus is repro- 

 duced by self- division, and that subsequently, when it has passed 

 into the form of fibre, the mode in which the nucleolus gives origin 

 to other structures is such as to imply even here the continued re- 

 production of its own substance — that mode being self-division. 



The author describes particularly the mode of origin of primary 

 and secondary membranes, and division of the cell. He considers 

 that the latter is initiated by self-division of the nucleolus into halves 

 which become " cytoblasts," and it is completed by the formation 

 out of these of two young cells, the walls of which, where in contact 

 with one another, form a septum dividing the parent cell into two 

 compartments. Thus for division of the cell there occurs no folding 

 inwards of a " primordial utricle," as maintained by Von Mohl, 

 nor any division of the contents of a parent cell into two parts, around 

 which contents are formed the walls of two young cells, as supposed 

 by Nageli and Hofmeister. On the subject of annular, spiral, and 

 other deposits in the vessels of plants, the author remarks, that when 

 the divisions of an annular or spiral fibre are not continued, but par- 

 tial and irregular, we have the reticular form, as well as an expla- 

 nation of the supposed tendency in vegetable fibre to anastomosis. 



The two spiral filaments composing fibre at first appeared to the 



