122 



For advanced students, needing a knowledge of more special 

 methods, Lee's Microtomisfs Vade-Mecum (5th edition, 1900), 

 and the notes of " technic " given in the many papers treating 

 of insect histology and development will furnish valuable sug- 

 gestions. All of the general methods of killing, fixing, 

 staining, etc., given in the following notes have been person- 

 ally used by the authors in studying insects. For those few 

 special cases of treatment of particular tissues and organs 

 introduced, which have not been tried by the authors, an 

 authoritative reference to the use of the method is always 

 given. ' 



It is hardly necessary to say that within certain limits 

 there is a great deal of difference in the practice of microto- 

 mists in the matter of method. In these brief notes it is in- 

 tended to outline a simple, straightforward course of proced- 

 ure which has been found by actual work on insect tissues to 

 give good results in such work. Even this plan has been 

 found difficult to adhere to, because a certain amount of 

 variation is sure to enter into the practice of any worker. 

 The student will find out for himself, however, as he gets 

 more and more familiar with the work, the advantages of 

 variation, and will be able to take advantage of the oppor- 

 tunities for modifying his practice presented by the many (at 

 first glance, confusingly many) suggestions of the standard 

 manuals of microtomic technic. The following three books 

 will be of special value for reference. 



Lee, A. B.: The Microtomisfs Vade-Mecum^ 5th edition, 

 1900. 



Whitman, C. O.: Method of Research in Microscopical 

 Anatomy and Embryology^^\^^$. 



Gage, S. H,: The Microscope^ 7th edition, 1901. 



