PREFACE TO THE SECOND EDITION. 



^Y endeavour, in the First Edition of this work, 

 to produce a cheap and popular guide to the use 

 of the Microscope, and thus to supply a want 

 which I had long believed it very desirable to 

 see supplied, has been rewarded by a success 

 which has fer exceeded my expectations. In the short space 

 of twelve months a large edition of Jive tJumsand copies has 

 'y been sold; and I am now called upon to prepare a Second 



Edition. 

 Mt efforts on this occasion have been directed to the thorough cor- 

 rection and revision of the whole work, rather than to extending it 

 with much new matter ; and I trust I shall have succeeded in making 

 the present Edition more free from blemish and more generally useful 

 to the public than the preceding one. In endeavouring to do so, I 

 have fully availed myself of the judicious suggestions and criticisms of 

 many kind friends ; and I wish to take this opportunity of acknow- 

 ledging the obligations I am under to those who have so generously 

 accorded to this small work, whatever its defects, their meed of appro- 

 bation. 



August 1S55. 



