144 LIFE OF A SLIME MOULD 



tion made by boiling in water bits of wood upon which the spor- 

 angia were growing. Germination will begin in about one day. 

 As the spore wall ruptures the contents escapes as a naked bit 

 of protoplasm (Fig. 89, B) which possesses a singular power of 

 motion. This motility is due either to the slow creeping or 

 streaming motion of the soft plastic body or more commonly the 

 body may possess a delicate thread or cilium (plu. cilia) (Fig. 

 89, C). These ciliated bodies are called zoospores. The cilium 

 is a highly sensitive organ which by rapid and rhythmical con- 

 traction and expansion beats the water and thus drives the body 

 along. While in this condition the zoospores are rapidly multi- 

 plied owing to the repeated splitting of the little bodies into two 

 similar parts. Finally this greatly increased number of indi- 

 viduals begins to come together in small groups (Fig. 89, D) 

 which in turn merge and so form large slimy masses termed Plas- 

 modia (sing. Plasmodium) which are quite destitute of all walls 

 and consist of a great number of nuclei surrounded by a watery 

 cytoplasm (Fig. 89, E). You will often find this plasmodial 

 stage of the slime mould on the under side of rotting limbs or 

 bits of wood in the forest as a sticky mass resembling in con- 

 sistency the white of an egg. The mucilaginous character of 

 the Plasmodium accounts for the name slime mould popularly 

 applied to these plants, also for the term myxomycetes, from 

 myxos, slime, and myces, mould or fungus. 



The Plasmodium possesses a sensitiveness or capability of 

 responding to external stimuli to a degree that is remarkable 

 when we consider the extreme simplicity of these plants. For 

 example, it avoids too strong a light and slowly moves toward 

 moisture and food. This accounts for your failure ordinarily 

 to notice it since it seeks the darkness and food in decaying 

 logs or the under surface of sticks and leaves. The motion is 

 brought about by little arm-like branches that flow from the 

 jelly-like Plasmodium and finally the entire plasmodium will 

 slowly follow along these lines with a complicated streaming 

 movement (Fig. 89, E). If bits of wood containing some of 

 the Plasmodium are placed in a damp chamber in the dark after 

 a time the plasmodium will be seen creeping up the sides of the 



