THE TRANSLOCATION OF PROTOPLASM 101 



In 1930, Kohler, 1 whilst studying the formation of hyphal fusions 

 in Neurospora sitophila, N. crassa and N. tetrasperma, observed 

 the streaming of protoplasm from cell to cell. He sowed some 

 conidia of Neurospora (sp. ?) thickly in a film of agar and soon 

 hyphal fusions took place between the germ-tubes. " The streaming 

 of the' protoplasm," says Kohler, "out of the connected germ- 

 mycelia toward the growing conidia-forming edge of the mycelium 

 could be splendidly seen. The cell- walls through which the stream 

 moved were, except for traces attached to the inside of the mem- 

 brane, re-absorbed so that the streaming, not confronted with any 

 important opposition, attained a surprisingly high speed, almost 

 comparable with the flow of blood through the capillaries of the 

 tongue of a frog. 2 The streaming is in full progress about 20 hours 

 after sowing the conidia at 18-20° C. It proceeds mostly by jerks, 

 but at higher speeds proceeds steadily." In view of the investi- 

 gations which have been made on the nature of the septa in the 

 Higher Fungi by Wahrlich and others, and in view of my own obser- 

 vations on the rapid passage of protoplasm through the small central 

 pore in the septa of Fimetaria fimicola and Pyronema confluens, I 

 am inclined to think that Kohler was in error in stating that in hyphae 

 of Neurospora in which streaming can be seen the septa have been 

 re-absorbed. Probably the septa in Neurospora have a small central 

 pore and are just as persistent as those in Higher Fungi generally. 



Investigations by the Author. — In the spring of 1932, whilst 

 studying hyphal fusions in the mycelium of Fimetaria fimicola, I 



1 E. Kohler, " Zur Kenntnis der vegetativen Anastomosen der Pilze. II.," 

 Planta, Bd. X, 1930, pp. 505-506. 



2 The rate of flow of protoplasm in various fungi will be found in the Table on 

 p. 109. The maximum rate observed was : for Rhizopus nigricans, 55 y. per second; 

 and for the Pyrenomycete, Fimetaria fimicola, 16*5 [x per second. According to 

 Michael Foster (A Text Book of Physiology, Part I, London, 1893, pp. 225-226), the 

 observed rate of flow of blood is : through the capillaries of the web of a frog's foot, 

 about 500 [i per second ; through the capillaries of mammals generally, about 750 y. 

 per second ; and through the capillaries of man, about 1000 [i per second. The rate 

 of flow of blood through the capillaries of a frog is therefore about nine and thirty 

 times greater than that of the maximum rate of flow of protoplasm through the 

 hyphae of Rhizopus nigricans and of Fimetaria fimicola respectively. It is evident 

 that the rate of flow of blood through the capillaries of frogs, mammals, and man is 

 far greater than the maximum observed rate of flow of protoplasm through the 

 hyphae of any fungus whatsoever. 



