HOW ANIMALS WORK. 



CHAPTER I. 



SOME MICROSCOPIC BUILDERS. 



YV7E are accustomed to consider the construction 

 VV of some finely proportioned building, or the pro- 

 duction of a beautiful casket richly carved and moulded, 

 essentially as work only to be attained by the creative 

 brain and skilled fingers of the highly trained human 

 craftsman. But to-day I would like to introduce you 

 to quite another type of craftsman or builder one who 

 cannot definitely be said to possess any imaginative 

 brains or deft fingers, and is destitute of sight and 

 special tools, and yet is capable of constructing out of 

 lime and silica the most exquisite caskets, spheres, 

 spires, cornucopias, fretted, pierced, and bearing the 

 most delicate sculpturings and tracery imaginable, yet 

 all on so minute a scale as only to be made visible by 

 the magnifying powers of the microscope. If we were 

 to look at one of these brainless, sightless workers under 

 the microscope after its tiny fairy mansion had been 

 dissolved away, we should see that it appears to be 

 just a minute blob of semi-transparent jelly, a speck 

 of protoplasm, capable of certain streaming movements, 



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