WONDERS OF THE MICROSCOPE 261 



not due to the colouring pigment, but is owing 

 to the air contained in them. 



The colouring 



Fig. 1 8 1. Shavings from the human beard 



matter is contained in the outer or cortical cell 

 layer. 



Most animal hairs make interesting objects for 

 microscopic investigation, and by a little practice 

 sections of hairs may be cut with a sharp razor, 

 after tying a little bundle together and dipping in 

 glue and allowing to dry, afterwards dissolving off 

 the glue. Hair sections sometimes are surpris- 



