I3 o RESEARCHES ON FUNGI 



of locomotion of their own. Doubtless they are moved passively 

 by the cytoplasm of the vacuolar walls. 



The true nature of Woronin bodies and what their function is 

 remain for the present unknown. Since they are present in apical 

 cells, it is possible that they are specialised parts of the protoplasm. 

 When once formed they are very persistent for, as Ternetz x has 

 pointed out, they can still be seen on the walls in exhausted cells. 



Pore Plugs and their Formation under Experimental Con- 

 ditions. — Observations on the manner in which protoplasm streams 

 from cell to cell in Fimetaria fimicola and Pyronema confluens 

 justify us in concluding that in these and other similar fungi each 

 septum in a mycelium is provided with a small, central, circular, 

 open pore through which protoplasm can pass, and often does pass, 

 with the greatest ease. The acceptance of these conclusions suggests 

 the following questions : when a cell in a living hypha dies naturally 

 or is killed by manipulation, does protoplasm flow through the 

 pores of the septa from the adjacent living cells into the dead cell ; 

 and, if not, what prevents it from doing so ? The answer to these 

 questions was obtained by means of some special observations which 

 will now be recorded. 



Some spores of Pyronema confluens were sown in a hanging drop 

 of cleared dung-agar, and they soon germinated. On one of the 

 next few days, when the mycelium was well grown, some of its 

 hyphae were operated upon with the help of a beading needle— a 

 slender cylindrical needle about two inches in length. The cover- 

 glass was removed from the van-Tieghem cell, inverted, and set on 

 a glass slide. Then the pointed end of the needle was heated in a 

 flame, and, whilst still very hot, was drawn rapidly across the 

 preparation in such a way as to pass through the dung-agar and 

 sever several of the long main hyphae (c/. Fig. 70, A, p. 137). 

 Immediately after the operation had been performed, the cover- 

 glass was set back in its old position on the van-Tieghem cell and 

 the broken hyphae were examined with the microscope. 



The operation in other hanging-drop preparations was performed 

 with an improved technique. The glass slide bearing the inverted 

 cover-glass was set under the low-power objective of the microscope 



1 C. Ternetz, loc. tit., p. 279. 



