10 



EVENmGS AT THE MICROSCOPE. 



and examine it near the base, vre see that it is very 

 slender, transparent, and colourless, covered ^vitll 

 strongly-marked imbrications, "udiich are not obtuse 

 teeth, but long, pointed, overlapping scales, about ten 

 of which complete a whorl. The fibrous portion is 

 moderately thick ; inclosing a wide pith of roundish 

 cells, set in two rows, that allow the rays of light to 

 be transmitted through their central parts. 



As we trace the hair upwards, by moving the stage 

 of the microscope, by and by it swells and rapidly in- 

 creases in thickness ; the imbrications are scarcely per- 

 ceptible ; while the pith- 

 cells have sreatlv ausjment- 

 ed in number and in breadth. 

 These are arranged in con- 

 fused, close-set, transverse 

 I rows, and are nearly opaque. 

 Still tracing up the same 

 hair, as we approach the 

 tip, the bark and fibrous 

 part become very thin ; tlie 

 cells are fewer and fewer 

 till they cease altogether, 

 and a long slender point, 

 of a clear yellow tinge, 

 without cells, presents transverse wavy lines of imbri- 

 cation scarcely projecting. 



The hair of the common Mouse is a pretty and in- 

 teresting object. In the larger specimens the fibrous 

 portion is reduced almost to nothing. The imbrications 

 project very little, but careful observation reveals slant- 

 ing lines proceeding from the "teeth;" which show 

 that the wliole Purtacc is clothed with long pointed 



lIAir. OF SAELE. 



