PREFACE. Vll 



pose Yet in almost all cases the observations bo used 

 have been subjected to renewed scrutiny, and havo 

 been verified afresh, or corrected where found defective. 



In order to relieve as much as possible the dryness 

 of technical description, a colloquial and familiar style 

 luis been given to the work ; which has been thrown 

 into the form of a series of imaginary conversaziones^ or 

 rmcroscopical soirees, in which the author is supposed 

 to act as the provider of scientific entertainment and 

 instruction to a circle of friends. It is proper to add, 

 however, that the precision essential to science haa 

 never been consciously sacrificed. A master may be 

 easy and familiar without being loose or vague. 



A considerable amount of information will be found 

 incidentally scattered throughout the work, on micro- 

 scopic manipulation — the selecting, securing, and pre- 

 paring objects for examination ; — an important matter, 

 and one which presents a good deal of practical difii- 

 culty to the beginner. Not a little help will be afibrded 

 to him, also, on the power to observe and to discriminate 

 what he has under his eye. In almost every instance, 

 the objects selected for illustration are common things, 

 such as any one placed in tolerably favourable circum- 

 stances, with access to sea-shore and country-side, may 

 reasonably expect to meet with in a twelvemonth'a 

 round of research. 



