INTRODUCTION. 



the executive of every microscopical society should en- 

 deavour to secure a copy of each for its library. 



If microscopical students would only peruse these older 

 works, and enter into communication and discussion with 

 their brother microscopists, much time and work would be 

 saved, and a great deal of that re-discovery which goes on 

 at the present day averted ; there is no other way of 

 avoiding repetitions except by the methods above stated. 



We might advance more rapidly, or more certainly at 

 least, if we asked, before performing any microscopical 

 operation, the reason why. We are too apt to do things 

 in a certain manner because some one who instructed us 

 in the art and mystery did so before us ; no inquiry was 

 made, but we did likewise. If the principles upon which all 

 operations are conducted were thoroughly understood by 

 all those who intend working with the microscope, much 

 labour would be saved, needless experiments avoided, slides 

 rendered more permanent, and microscopical research 

 brought more into favour on account of some of the barriers 

 which now obstruct progress having been broken down. 



It is in this direction that a treatise may be useful to the 

 student ; objects themselves, whether of animal, vegetable, 

 or mineral origin, are best treated of in works entirely 

 independent of practical microscopy; an organism, how- 

 ever minute, has its life-history, and it should be the aim 

 of each student to be useful in his generation by endeavour- 

 ing to furnish an accurate account of the cycle of existence 

 of some member of the animal or the vegetable world. 



Of course, before he can be expected to occupy himself 

 with original research, he should be fairly acquainted with 

 all that has been done before upon the subject ; but above 

 all must he be familiar with the instrument with which he 

 works, and the methods whereby certain results may be 



attained. 



B 2 



