72 VIGNETTES FROM INVISIBLE LIFE. 



Though comparatively large in their general outline, 

 being about 1-1 5th to l-25th of an inch in diameter 

 and just discernible by the unaided eye, they are of 

 such extreme tenuity -as scarcely to bear the slight- 

 est touch, and, being extremely active, are thus very 

 difficult beings to manage under the microscope. 

 You want to stop its gyrations in order to examine 

 its organisation, and having so large a creature to 

 deal with, apply a gentle pressure to the covering 

 glass with this object. Now, unless you are very 

 gentle indeed, you find the Bursar has outwitted you, 

 and disappeared in a thin cloudy mucous film. After 

 many attempts you may succeed, and then are well 

 repaid for your trouble, for these animals furnish 

 the finest examples of ciliary action it is possible 

 to imagine. 



Like the individual, the whole lot in a locality 

 will sometimes vanish suddenly and simultaneously 

 (Bursars and Stentors alike) ; and, " like the base- 

 less fabric of a vision faded, leave not a wrack 

 behind." 



