55 



material and obviates the necessity of culluring or maintaining 

 vegetative plasmodia for future use. One convenient method of 

 obtaining sclerotia is as follows: Place some decaying wood, in 

 which a plasmodium is growing, on absorbent paper which can 

 be moistened and kept moist. In the course of time, some part or 

 all of the Plasmodium will creep from the wood to the surface of 

 the paper and after this has occurred the wood may be removed. 



Fig. 2. A photomicrograph of a portion of a plasmodium showing the thick 

 vein-like channels along which rapid protoplasmic streaming takes place. 



Following this, the plasmodium is subjected to gradual dessica- 

 tion by leaving the paper to which it is clinging under a bell jar 

 or similar vessel. This vessel should be provided with a small 

 opening through which a slow exchange of gases can take place 

 between the atmosphere of the vessel and the external atmo- 

 sphere. The optimum rate of dessication is unknown but the 

 writer has found it effective to allow about twenty-four hours 

 for completion of the process. If dessication is too rapid horny 

 non-viable masses are formed. In the process of sclerotization 

 Plasmodia collect into more or less compact masses and cleave 

 into roundish or polyhedric cells. When fully formed, the sclerot- 



