46 THE STUDY OF ANIMAL LIFE CHAP. 



waited results. There were the corpses of the Rotifers 

 plain enough, but they did not revive even in abundant 

 moisture. What was the explanation ? The eggs of 

 these Rotifers survived, they developed rapidly, they 

 reinstated the family. And of course it is much easier 

 to understand how single cells, as eggs are, could sur- 

 vive being dried up, while their much more complex 

 parents perished. In some cases, however, it has been 

 satisfactorily demonstrated that even the adult Rotifers 

 may survive after being left for some time "as dry as 

 dust." There is no doubt, moreover, that certain simple 

 " worms," known as " paste-eels," " vinegar-eels," etc., 

 from their frequent occurrence in such substances, can 

 survive desiccation for many years. Repeated experi- 

 ments have shown that they can lie dormant for as long 

 as, but not longer than, fourteen years, and it is inter- 

 esting to notice that the more prolonged the period of 

 desiccation has been, the longer do these threadworms 

 take to revive after moisture has been supplied. It 

 seems as if the life retreated further and further, till at 

 length it may retreat beyond recall. In regard to plants 

 there are many similar facts, for though accounts of the 

 germination of seeds from the mummies of the pyramids, 

 or from the graves of the Incas, are far from satisfactory, 

 there is no doubt that seeds of cereals and leguminous 

 plants may retain their life in a dormant state for years, 

 or even for tens of years. 



But desiccation is only one illustration out of a score 

 of the manner in which animals keep their foothold 

 against fate. It must be admitted that they are often 

 unsuccessful ; the individual has often fearful odds 

 against it. How many winged seeds out of a thousand 

 reach a fit resting-place where they may germinate ? 

 Professor Mobius says that out of a million oyster em- 

 bryos only one individual grows up, a mortality due to 

 untoward currents and surroundings, as well as to hungrv 



o * 



mouths. Yet the average number of thistles and oysters 

 tends to continue, ' So careful of the type she seems, so 

 careless of the single life." Yet though the average 



o o o 



usually remains constant, there is no use trying to ignore, 



