THE TRANSLOCATION OF PROTOPLASM 



95 



septum was found to have a simple central open pore, devoid of a 

 closing membrane, through which passed a single thread of proto- 

 plasm ; only in one instance (an unidentified fungus) was a more 

 complicated arrangement met with. In a 

 clamp-connexion each of the two septa has a 

 pore (Fig. 52, No. 16). The thread of proto- 

 plasm passing through a pore is about 1 • 0-1 • 5 [z 

 thick and consists, externally, of a thin layer 

 of homogeneous protoplasm and, internally, as 

 may be seen in favourable preparations, of 

 granular protoplasm. A pore in a septum 

 arises not through subsequent resorption of a 

 piece of membrane, but is there from the first 

 owing to the septum never having become 

 fully formed at its centre. Cell-division in 

 septate hyphae is therefore never complete. 

 Of this Wahrlich obtained convincing evidence 

 from a young culture of Achorion Schonleinii 

 (Fig. 49, No. 8). A septum begins its formation 

 as a ring-like projection from the inside of the 

 wall of the mother-cell and gradually pushes 

 its way toward the centre of the cell. However, 

 it never extends completely to the centre of 

 the cell so that, when it ceases to develop, it 

 is already provided with a median pore. 1 



So far as the function of the protoplasmic 

 bridges is concerned, Wahrlich expressed the view that they serve 

 as ways for the transportation of material and, in particular, of 

 granular protoplasm. In support of this he pointed to the fact that 



Fig. 51. — Coprinus at- 

 ramentarius, a 



basidium. After 

 Wahrlich. Mag., 

 1800. 



Fia. 50 — cont. 



the pedicel with the base of the spore, the Roman numerals indicate the 

 different membrane-layers ; C, the top of the pedicel torn away from the 

 spore, a granule of protoplasm is left sticking in the pore ; treated with chlor- 

 zinc iodine. From Wahrlich's Zur Anatomie der Zelle bei Pilzen und Fadenalgen. 

 Magnification : No. 34, A, 600 ; the others 1800. 



1 Wahrlich believed that, in Spirogyra, and probably also in Fungi, the primary 

 wall of the septum begins its development as a true ring-fold formed within a con- 

 striction of the protoplast. 



