CHAPTER I. 

 INTRODUCTORY. 



PLEASURES AND ADVANTAGES OF PHOTO-MICRO- 

 GRAPHY. CAMERA LUCIDA. CIRCULATING 

 SLIDES. THE LITTLE SPECIAL APPARATUS 

 NEEDED. USE OF EYEPIECES. FIRST 

 ATTEMPTS. 



Although the sense of sight enables us to see 

 the many forms around us, there is a world as 

 absolutely invisible to the unassisted eye as the 

 familiar objects of life are invisible to the blind. 

 To those who have eyesight, however, the micro- ^ T>vP 

 scope bestows as great a power of vision as the y&s 

 gift of sight would bestow upon the blind, for it 

 enables them to penetrate the secrets of nature's 

 realm, which without such assistance would for 

 ever remain a mystery. 



A very small magnification will often reveal de- 

 tails of construction sufficient to call forth exclama- 

 tions of surprise ; and, indeed, with microscopists 

 it is a matter of common knowledge that whole 

 insects or parts of plants viewed under a low power 

 will excite more astonishment than the resolution 

 of a difficult diatom under the very highest power. 

 For instance, a spider magnified ten times seems 



