INTRODUCTION 



The technic of fifty years ago, judged by modern standards, was 

 very crude; the microscopes of that time, while no worse than the 

 preparations, could not show the details which interest investigators 

 today. Many objects, like pollen grains, were examined without 

 sectioning. The pollen grain of a lily, if placed upon a dark back- 

 ground, is barely visible to the naked eye; but with modern methods, 

 such a pollen grain can be cut into fifty sections, the sections can be 

 mounted and stained without getting them out of order, a photo- 

 micrograph can be made from the preparation and a lantern slide 

 from the photomicrograph, and finally there appears upon the screen 

 a pollen grain ten feet long, with nuclei a foot in diameter, nucleoli 

 like baseballs, and starch grains as large as walnuts. Impossible as 

 this may seem, such preparations are easily made, and investigators 

 are now showing clearly the nature of structures which, only ten years 

 ago, were good subjects for philosophical botanists, who are happier 

 with preparations which leave more freedom for the imagination. 



Modern technic is very complicated, and to the beginner the 

 numerous details may seem bewildering, but every detail must be 

 mastered if the final mount is to be worth anything. By following 

 the various schedules, even in a slavish way, fairly good mounts 

 have been obtained at the first trial; but to gain any independence 

 and to secure the best results, the student should understand the 

 reason for each step in the whole schedule. Only then will he 

 become able to make such variations as individual cases may require. 

 The horizon should broaden as the student advances, and he should 

 see that even such diverse methods as the Freehand Method, the 

 Venetian Turpentine Method, and the Paraffin Method have 

 certain fundamental principles in common. 



Everyone who intends to become an investigator should study 

 technic with the intention of using it in his researches. Many regard 

 the making of mounts as mere mechanical drudgery which can be 

 done by an assistant, but such armchair investigators are likely to 



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