A LOG AND SOME MYCETOZOA. 135 



ning of October last, the temperature fluctuated greatly ; but tbey 

 point to the conclusion that for the developments wbich took place 

 a mean temperature of 19° or 20° C. was most favourable. 



To maintain the activities of plasm, however, much moisture 

 is necessary, and occasionally, when the atmosphere was dry and 

 hot, the log was watered to replace loss by evaporation. It was 

 largely the combination of warmth and moisture which kept 

 matters going. 



As regards the behaviour of plasmodia within the wood, we 

 can only judge by inference. When in that position they obvi- 

 ously cannot have the same freedom of movement as those which 

 openly spread over dead leaves and tree stumps as networks of 

 amoeboid plasm. Their liberty is, indeed, much restricted, and 

 the controlling factors are not wholly apparent ; but at least 

 some of them are clear. In rotting timber, decay mainly follows 

 the direction of the grain ; moisture flows by capillary attraction 

 or gravitation along the channels of decay ; and spores, swarm- 

 spores and Plasmodia are liable to be carried along by the cur- 

 rents. Thus, the more extended patches of Lamproderma always 

 developed on the log in a longitudinal direction, parallel with the 

 grain. Again, at one extremity the wood has partially split ; the 

 rain finds its way down the fissure until it reaches an outlet on the 

 sawn face at the end of the log ; and the most abundant develop- 

 ments of Stemonitis and Lamproderma were round about this 

 outlet. Other cases suggested, not gravitational, but capillary 

 effects. For example, on the highest and driest part of the log 

 is a spot where stumps of shoots remain fixed in the wood ; and 

 Plasmodia of Lycogala and Lamproderma have come to the sur- 

 face by way of the crevices surrounding these insets. It is possible 

 that increases in the volume of plasm, by growth or absorption of 

 moisture, may have found an outlet in the upward direction 

 as the line of least resistance ; but heat or dryness of the air would 

 undoubtedly set up capillary currents of moisture from the 

 interior to the surface of the log, and these might easily assist in 

 bringing plasmodia to the light of day. Such conclusions by no 

 means preclude other and more obscure reasons for emergence, 

 probably inherent in plasmodia ready to form sporangia. 



Not many specimens were removed from the log ; they were 

 mostly left to take their natural course, and soon disappeared. 

 Birds and insects, wind, rain and falling leaves, quickly destroyed 



