INTKODUCTION. TJiJ 



subjected to inspection by it, and will then disclose new beauties 

 and fresh sources of knowledge. Under it the point of the finest 

 cambric needle looks like a crow-bar, grooved and seamed with 

 scratches; the eye of the fly is seen to consist of thousands of eyes; 

 and the dust on the butterfly's wing appears to be what it really is, 

 scales laid on with all the regularity of shingles or slates on a house ; 

 while to prepare and examine these simple objects requires no great 

 skill and no elaborate apparatus. 



2. As a means of imparting instruction to the young, the micros- 

 cope has now become indispensable. The changes which of late 

 years have taken place in the views held by our ablest men in regard 

 to the best education are too well known to need even mention. 

 No education that does not include a knowledge of natural science 

 is now regarded as complete, and there is a very wide range of the 

 most essential and practical knowledge that can be reached only 

 through the microscope. Thus, when we look at a leaf with the 

 naked eye, we see but a green mass of matter, possessing a certain 

 beautiful form, it is true, but disclosing none of those organs which 

 render it more complicated and wonderful than anything ever pro- 

 duced by our most skilful mechanics. Looked at by the micro- 

 scope, however, this same leaf is found to be made up of innumer- 

 able parts, each one of which is highly complex and beautiful; it is 

 furnished with mouths for breathing, with cells for storing, digest- 

 ing and assimilating nutriment, and with ribs for strengthening its 

 structure; and all this, which is perfectly invisible to the unassisted 

 vision, becomes distinct and obvious when we call to our aid a 

 microscope of even moderate power. It is true that much of this 

 may be taught by means of books, engravings and verbal descrip- 

 tions, but every one knows that for distinctness and impressiveness 

 the very best engravings fall far short of a view of the real object. 



3. As an instrument of research, the microscope now occupies a 

 position which is second to none. There is hardly any department 

 of science in which a student can hope to reach eminence without a 

 familiarity with the microscope. Botany and Zoology have been 

 developed almost wholly by its aid, and so necessary is it in the 

 study of these sciences, that Schleiden, one of the most successful 

 of investigators says of it: " He who expects to become a botanist 

 or a zoologist without using the microscope, is, to say the least of 

 him, as great a fool as he who wishes to study the heavens without a 

 telescope." In chemistry its services have been very important, and 

 in geology and mineralogy it has opened up new fields of research 

 which almost promise to revolutionize these sciences. Medicine has 



