146 



white sand that had been first thoroughly washed and 

 cleaned, 



moss, 



bits of living twigs of Acer Pseudo-Platanus oc, also 

 thoroughly washed and cleaned, 



water. 



After sterilization of the flasks and infection with pure 

 cultures, the fungus was permitted to grow to a height 

 of 18 — 20° C. for the space of one month, and then — 



Fig. 1. Growths of the toadstools derived from pure culture. 

 Mr. B. |. van Tongeren del 



in November 1916 — the flasks were placed in a room, 

 where in winter, the température remained slightly over 

 0° C. In October 1917 two normal toadstools had 

 developed in one of the flasks (Fig. XIV), but while the 



