THE TRANSLOCATION OF PROTOPLASM 



131 



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and the pointed end of the beading needle, without being heated, 

 was brought into contact with a particular cell and this was pressed 

 upon, with the result that its protoplasm died and became dis- 

 organised, often with- 

 out its cylindrical 

 cell-wall being rup- 

 tured (c/. Fig. 71, A 

 andB, p. 138). The 

 average length of the 

 cells in the hyphae 

 to which the needle 

 was applied was 

 0-13 mm. 



It was found that 

 the protoplasm of a 

 cell injured by the 

 needle always died 

 as a whole, i.e. 

 throughout the 

 length of the cell and 

 right up to its two 

 septa (cf. Fig, 71, B), 

 and that the injury 

 was not transmitted 

 to the two adjacent 

 cells, which remained 

 living. 



Also, immediately 

 after a cell has been 

 killed, it was found : 

 (1) that the two 



septa separating the dead cell from the two adjacent living cells, 

 which previously were plane, become convexo-concave with the 

 convex side directed toward the lumen of the dead cell ; and (2) that 

 the pores of the two septa become blocked by a plug in consequence 

 of which the escape of living protoplasm from the adjacent living cells 

 into the dead cell is prevented. 



Fig. 



67. — Pyronema coyifluens. Diagrams to illustrate 

 the septal pore and its employment as a passage-way 

 for protoplasm as this streams in a mycelium from 

 cell to cell. To the left, a septum in face view : 

 it is about 10 jj. in diameter and its central pore 

 about 1 ft in diameter. To the right, parts of two 

 adjacent cells of a hypha in median longitudinal 

 section. As indicated by the arrows, the main 

 mass of the protoplasm, which is finely granular, 

 is streaming from one cell to the next through the 

 pore of the septum. The vacuoles are large and 

 have very thin non-granular protoplasmic walls 

 which are not moving. Attached to the walls of 

 the vacuoles in temporarily fixed positions are 

 some tiny, oval, highly refractive bodies. These 

 at times change their position on the wall of a 

 vacuole, without reference to the direction of the 

 current of the granular protoplasm. Magnification, 

 3240. 



