6 



of mycelium forming a tangled net-work and filled with very- 

 irregular tubercular masses, ranging in size from .5-5 cm. in 

 diameter. 



These tubercles or sclerotia appeared to be enlarged portions 

 of the mycelial threads and were twisted, lobed and convoluted 

 in a very irregular manner. On making sections of these it was 

 found that they consisted of two distinct parts, an outer wall 

 about 2 mm. thick and an inner cavity which either contained 

 only air or was filled with a gelatinous substance. This cavity 

 was observed at this time, in the fall, to be in a state of negative 

 pressure. Those tubercles which had their cavities filled with 

 air would float in water while those containing the gelatinous 

 substance would sink. It was therefore easy to determine, with- 

 out injury, the character of the different tubercles in this respect. 



The wall of the tubercle consisted of a dense weft of mycelium 

 forming apparently a pseudoparenchyma. This was most com- 

 pact toward the outer surface and became more open toward the 

 interior, terminating at the surface of the interior cavity in numer- 

 ous free ends. These hyphal ends were about 7 ii wide and 

 quite irregular in form. When the cavity contained the gelati- 

 nous substance, this was found to be everywhere penetrated by 

 fine branching threads about 3 //. wide, of uniform size, and run- 

 ning in nearly straight lines. The.se threads, easily distinguished 

 from the hyphae previously mentioned, seemed to have their 

 origin in the outer wall of the tubercle but just how could not be 

 made out. 



There was also observed in the jelly-containing tubercles, cer- 

 tain peculiar bodies which were supposed from their appearance 

 to be crystals of calcium o.xalate. These were not numerous and 

 were developed chiefly among the free hyphae on the inner sur- 

 face of the wall. A portion of a hyphal thread would be en- 

 larged into a globular form about 40// witlc and would contain 

 within it a spherical body about 22 // wide and marked with fine 

 radiations. 



The larger tubercles in many cases had the appearance of 

 being made up of a fused mass of smaller ones. One such con- 

 glomerate mass measured over S cm. in width. 



