MICROSCOPE AND AGRICULTURE 



along with the animal's excrement. If then the 

 eggs are blown, or carried by some means to water 

 they will continue their development, on dry soil 

 they cannot long survive. Each egg gives rise to a 

 little organism which swims freely in the water ; it is 

 shaped like a blunt-ended cone when extended and 

 is roughly oval when contracted. Its body is 

 covered with little whip-like structures similar to 

 those of the slipper animalculae, and it is due to 

 the lashing of these little whips that the creature 

 moves through the water. If we found one of these 

 young flukes in some pond water we might be 

 forgiven for thinking it to be some near relative 

 of the slipper animalcule. When our subject finds 

 a living water snail it enters its breathing organs, 

 becomes affixed to their walls and loses its covering 

 of little whips. It becomes transformed into a 

 shapeless mass which later develops into an elon- 

 gated structure, quite unlike the free swimming 

 creature which took shelter within the snail. Next, 

 a migration is made to the liver of the snail where 

 birth is given to, from fifteen to twenty, curious 

 little heart-shaped organisms each with a tail about 

 twice as long as its body. These little creatures 

 escape from the snail and swim freely in the water 

 for a time. Eventually they make their way to 

 herbage growing by the waterside, affix themselves 

 thereto and become surrounded with a hard coat 

 capable of resisting the effects of hot sun or drying 

 winds. Should this herbage be eaten by cattle, the 

 apparently lifeless young fluke bestirs itself, loses its 



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