XXIII 

 LATENT LIFE 



WHEN a saucer of paste is left forgotten 

 on a shelf it becomes the soil for an 

 abundant growth of minute fungoid plants or 

 molds. But in many cases it also shows a popu- 

 lation of " paste-eels," transparent microscopic 

 threadworms, the germs of which have been wafted 

 into the saucer by air-currents. Millions of the 

 closely related " vinegar-eels " are sometimes to be 

 found in vinegar-cruets which have been left 

 uncorked. The worms seem to thrive in that 

 strange habitat, and they make the vinegar turbid 

 with their multitudes. Now, the paste-eels and 

 vinegar-eels (and other " Anguillulid Nematodes ") 

 are noteworthy for their capacity for latent life. 

 They can remain dried-up, without signs of any 

 activity, for years, and yet become lively again 

 when restored to moisture and other appropriate 

 conditions. It seems that some of them can endure 

 the " suspended animation " for fourteen years, 

 and that the time required for revivification is 

 proportionate to the duration of the latency. The 

 eel worm which causes "ear-cockles " in wheat is 

 able to lie latent in its gall for over twenty years. 

 The same phenomenon is illustrated by some mites, 



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