100 



RESEARCHES ON FUNGI 



helps us to understand not merely the phenomenon of protoplasmic 

 streaming in the mycelium of certain Discomycetes, Pyrenomycetes, 



Fig. 55.— M icrosporon felineum. The pore in the septum, and the 

 mode of formation of a septum, in a macroconidium (fuseau). 

 A, a macroconidium in water : the median pore in each septum 

 cannot be seen. B and C, fixed in acetic acid and stained with 

 methylene-blue. B, a very young macroconidium before septa 

 have begun to develop. C, an older macroconidium : the septa 

 are developing as annular ingrowths from the lateral wall ; the 

 protoplasm, slightly contracted from the lateral wall, is con- 

 stricted at each partially formed septum. D, a large macro- 

 conidium with the outer wall and the septa much swollen with 

 chlor-zinc iodine and the protoplasm darkly stained with iodine : 

 the central pore in each septum can be readily seen. E, a 

 diagrammatic representation of a median-longitudinal section 

 of a living macroconidium showing a median pore in each septum. 

 F, a diagrammatic cross-section of the macroconidium E, 

 showing the outer wall, a septum, and a septal pore. Drawn 

 by A. H. R. Buller and P. H. Gregory. Magnification, 1100. 



and Hymenomycetes, but also how it is that a multicellular 

 fungus can develop and react to external stimuli in a unitary 

 manner. 



