DAMPING OFF. 255 



occur so regularly and at about 30/x. to 40^ distant that the resem- 

 blance to septa is very striking if they are not really septa. If 

 they are septa they are formed only after the protoplasm has 

 passed these points. It may be that the growth of the tube was 

 arrested for a certain length of time and the walls were formed 

 while it was in this quiescent condition, or the growth of the tube 

 may be naturally periodic. The protoplasm is coarsely granular, 

 presenting here and there rather faint vacuoles, but there are so 

 far as examined, no septa separating the protoplasm into distinct 

 portions. The course of the tube is slightly sinuous, and also in 

 an ascending position as the glomerule lay on the glass slip. 

 Perhaps this was for the purpose of emerging from the water. 

 After an examination the cultures were returned to the moist 

 chamber. 



While the fungus is progressing through a prothallium when 

 one of these spore balls becomes mature, some of the cells lying 

 adjacent to healthy cells of the prothallium germinate and grow 

 directly into the new cell host. In doing so the germ tube is very 

 much smaller since less energy is expended in making the per- 

 foration through the wall. After emerging from the wall in the 

 new host cell the tube does not enlarge to the size of the tube 

 when germination takes place in water on the glass slip, but re- 

 mains about the same size as that of the perforation in the wall, 

 until it reaches the center of the cell lumen where it enlarges into 

 a rotund body as described above. Here it soon grows into the 

 botryoid hyphal mass again. Other cells may germinate and 

 course for a considerable distance over the surface of the pro- 

 thallium and enter new host cells quite distant from the 

 hyphal mass, but this has not been observed. In some cases 

 more than one cell lying quite close to a new host cell will ger- 

 minate and grow into the same. From the observations thus far 

 made I should judge this to be quite common but not general. 



The first ovoid portion of the mycelium in the center cf the cell 

 of the host is considerably larger than the curved branch which 

 develops at its apex and frequently larger than any which follow. 

 The more slender form of these branches and the close apposition 

 of the branches to the primary enlarged ovoid portion suggests a 

 striking resemblance to an oogonium and antheridium. Thus far 

 have not seen any conclusive evidence that these organs are I 



