I44 RESEARCHES ON FUNGI 



the high power of the microscope. 1 No protoplasmic movement 

 could be detected. A powerful electric lamp with a focussing screw 

 was then used as a source of light. After much manipulation of the 

 light, the mirror, and the condenser, streaming of the protoplasm in 

 several hyphae was observed. The streaming protoplasm appeared 

 as a very faint grey cloud moving forward in one direction (Fig. 74, 

 A). In some of the hyphae the movement was very rapid, just as 

 in Fimetaria fimicola and Pyronema confluens. As the protoplasm 

 came up to a septum it seemed to pass through it with the greatest 

 ease, and streaming was observed in one direction through about a 

 dozen long cells in succession. The hyphae in which streaming was 

 very active appeared to be less vacuolated than those in which the 

 protoplasm was at rest or moving very slowly. 



Protoplasmic streaming, like that just described, was seen in a 

 number of hanging- drop preparations made on different days. 

 Usually artificial light was employed, but it was found that streaming 

 could be observed even by daylight when this is obtained from 

 white clouds strongly illuminated by the sun. 



As it is not easy to illuminate a hypha in which streaming is 

 taking place so that the movement of the protoplasm can be actually 

 observed and as, in consequence, other investigators may have 

 difficulty in detecting the phenomenon, I shall here record that 

 Dr. E. S. Dowding, Dr. G. R. Bisby, and two other observers, after 

 examining my cultures, all declared that they also had been able 

 to perceive the faintly visible, cloudy protoplasm flowing en 'masse 

 rapidly from cell to cell. 



In a hypha of Rhizoctonia solaniin which streaming is in progress, 

 usually no large vacuoles are in contact with the septa ; and hence 

 an afferent cone of protoplasm approaching a septal pore and an 

 efferent cone of protoplasm proceeding away from a septal pore, 

 such as have been described for Pyronema confluens, were not 

 observed. However, careful focussing at the level of a pore when 

 protoplasm is streaming through it enables one, under favourable 

 conditions, to observe that the stream of protoplasm, immediately 

 after passing through a pore, rapidly widens out in the next cell. 



In hanging-drop cultures of Rhizoctonia solani, Coprinus 

 1 Zeiss microscope, 1900, Ocular No. 4, Objective FF, dry system. 



