1 82 THE STORY OF ANIMAL LIFE 



in an hour, which cannot be repaired in a day. 

 But when all is done that servants and helpers 

 can accomplish, the real business remains to be 

 done. Is there among the specimens one which 

 has not been thoroughly overhauled by other 

 writers, one whose every detail of structure is not 

 already to be found printed in a book ? That 

 one must be examined with the utmost accuracy. 

 If it is big enough, it must be dissected, and every 

 part recorded and figured in diagrams. But sup- 

 pose it is a small creature, whose parts can only 

 be seen under the microscope, a long series of 

 processes are necessary before it is ready for use. 

 In its fresh state, it contains a quantity of water, 

 and if left to itself would shortly decompose. 

 Even if already immersed during carriage in va- 

 rious preservative fluids, it still contains much 

 water, and, if so, neither will it keep for an indefi- 

 nite length of time, nor could it be satisfactorily 

 examined under the microscope. It must be 

 soaked in one of various chemical solutions, to 

 harden and preserve it. If very small indeed, a 

 mere speck, it perhaps only needs to be transferred 

 to a fluid in which it can be " mounted " and placed 

 under the microscope. But with the vast majority of 

 specimens, an immense amount of labour is needed 

 before they are ready for inspection under the 

 microscope. 



This will easily be understood if we reflect 

 for a moment on the way in which objects are 

 examined under the microscope. For purposes 

 of scientific investigation, they are rarely looked 

 at under light that falls upon their surfaces, that 

 is to say, by reflected light ; for this method can 

 show nothing but details which are external and 

 comparatively unimportant. They are seen by 



