INTRODUCTION. 



To know the origin of any object, event or act, is always of in- 

 terest. To know what lead up to a certain acceptable innovation or 

 aid is pleasing to everyone, and often important to the historian of 

 any department of the world's work. What was the form of the first 

 analytical key, who made it and what induced him to make it, are in- 

 teresting questions that the writer at least cannot answer. Such 

 tables have become very popular in the various departments of bot- 

 any and of zoology, but who originated them is not known; nor 

 when the first was published, nor where. Like many other good 

 things, these keys may have been the result of simultaneous thought 

 and experiment on the part of several workers that felt the need of 

 some outside aid to the inside treasures of the ever increasing mass 

 of scientific knowledge. But to whomsoever belongs the credit of or- 

 iginating these devices, to him belong much praise and many hearty 

 thanks. 



That analytical keys were needed is proved by their popularity. 

 They are welcomed by the student in all the sections into which Na- 

 ture is for convenience divided. It is true that there are some ob- 

 servers who scoff and laugh in derision when "keys" are mentioned, 

 but these few belong to that r.lass, fortunately limited, whose mem- 

 bers are unable to use them. There are persons that seem to be de- 

 ficient in those mental qualities that make the use of si-ch tables a 

 pleasure and a delight, as there are others unable to arrange even 

 the simplest of keys. If in a scheme of the kind there are three 

 groups, a blue, a black and a green, these unfortunate opponents of 

 keys seem unable to decide what to do next, when the specimen hap- 

 pens to be green while the first description in the list calls for a blue 



