10 



EVENINGS AT THE MICROSCOPE. 



long, pointed, overlapping scales, about ten of which 

 form a complete ring, or whorl, as it is called. 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 (b), by moving the 

 stage of the microscope, by-and-by it swells and 

 rapidly increases in thickness ; the imbrications are 

 scarcely perceptible ; while the pith-cells have greatly 

 augmented in number and in breadth. These are ar- 

 ranged in confused close-set, transverse rows, and are 

 nearly opaque. 



Still tracing up the same hair, as we approach the tip, 

 the bark and fibrous part become very thin ; the cells are 

 fewer and fewer till they cease altogether, and a long 

 slender point, of a clear yellow tinge, without cells, pre- 

 sents transverse wavy lines of imbrication scarcely pro- 

 jecting. 



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

 esting object. In the larger speci- 

 mens the fibrous portion is reduced 

 almost to nothing. The imbrica- 

 tions project very little, but care- 

 ful observation reveals slanting 

 lines proceeding from the "teeth ;" 

 which show that the whole surface 

 is clothed withlarge pointed scales, 

 which are very thin, and lie close. 

 The pith consists of large flattened 

 cells, arranged thus : one row 

 passes up through the centre, and 

 other similar ones are set in a 

 circle around it, so that a longitudi- 

 nal section would show three paral- 

 lel rows. These cells are translucent, and some of them 



HAIR OP MOUSE. 



