THE TRANSLOCATION OF PROTOPLASM in 



fixed, whereas in hyphae in which the streaming was rapid the 

 vacuoles were torn away from the sides of the hyphae and were 

 carried with the stream through the pores of the septa from cell to 

 cell in the manner already described for Fimetaria fimicola. The 

 maximum rate of flow of the protoplasm actually measured (deter- 

 mined by observing the rate of movement of the vacuoles) was 

 approximately 0-5 mm. per minute or 3-0 cm. per hour. 



In the mycelium of Gelasinospora tetrasperma, just as in the 

 other septate mycelia investigated, the rate of movement of the 

 protoplasm is proportional to the rate of growth of the hyphae : 

 in other words, the more rapid the growth, the faster does the 

 protoplasm move and, the slower the growth, the slower does the 

 protoplasm move. When growth ceases, the movement of the 

 protoplasm comes to a standstill. 



A mycelium of Gelasinospora tetrasperma had grown throughout 

 a shallow, widely spread, hanging drop of malt-agar and had largely 

 exhausted the culture medium, so that the hyphae had almost 

 ceased to elongate. As was to be expected, streaming of the proto- 

 plasm along the hyphae could no longer be observed. The cover- 

 glass of the van-Tieghem cell was removed, three or four tiny drops 

 of fresh culture medium were placed at several places on the surface 

 of the old drop, and then the cover-glass was put back in its place. 

 Within a few minutes, growth of the mycelium was resumed. 

 Hyphae grew into each fresh drop of culture medium, thickened, 

 branched and rebranched ; and, in from one to two hours after the 

 new drops had been added, the protoplasm in the mycelium could 

 be seen streaming rapidly from cell to cell out of the older hyphae 

 into the newly formed, rapidly developing systems of hyphae and 

 toward their growing points. In a single much branched hyphal 

 system, at each fork, the entering stream of protoplasm divided and 

 on this account gradually slackened its pace, but its movement could 

 still be detected even in the terminal hyphae. 



Pyronema confluens.— Pyronema confluens (Fig. 61) is a well- 

 known Discomycete with tiny pinkish confluent fruit-bodies, often 

 seen on burnt ground. Its sexual phenomena have been investigated 

 cytologically by Harper, Claussen, Gwynne-Vaughan, and others, 

 and the conditions under which it grows and develops its fruit-bodies 



