170 ANNUAL OF SCIENTIFIC DISCOVERY. 



THE MICROSCOPE. 



It is hardly correct to say that what eyes are to the blind the micro- 

 scope is to those who see. There is really no comparison between 

 those who can not see and those who see only a little. The microscope 

 is, in fact, an instrument which assists the sight in the same way as 

 short-sighted persons are enabled to see more correctly than those 

 who are long-sighted. The nearer we can place our eyes to an object 

 and see it, the better we see. If one person sees clearly at eight 

 inches, and another sees as plainly at six inches, the latter will see 

 more of the object he looks at. The glasses of the microscope ena- 

 ble all observers to bring their eyes closer to an object when it is seen 

 than is possible for the natural eye. Hence the great object of all 

 microscope-makers is to construct glasses that shall enable the observ- 

 er to get his eye as near as possible to the object. Twenty-five years 

 ago it was considered the highest attainment of microscope-making, 

 that achromatic instruments were made Avhich would work with 

 lenses that were brought within | of an inch of the object looked at. 

 Since then, the machinery of the microscope has been greatly im- 

 proved, and one of the great microscope-making houses of London 

 is producing object-glasses of -^ of an inch focus. Just in propor- 

 tion as these glasses are produced in working order, do new conditions 

 of matter unfold themselves to the observer. It is hardly possible to 

 conceive of any instrument producing more wonderful results than the 

 microscope, which, by enabling us to see better, develops the extraor- 

 dinary powers that are possessed by the human eye for adding to the 

 facts which constitute the basis of those general laws which are the 

 sciences of natural history and physiology. 



Although the microscope reveals the minuter conditions of the 

 existence of mineral bodies, there is a repetition in the forms of these 

 bodies, and a resemblance- between the forms seen by the naked eye 

 and those revealed by the microscope that renders this instrument of 

 less use in the inorganic kingdom than in the organic kingdom of 

 nature. It is in the detection of minute forms of plants and animals, 

 and in the unraveling of the minute structure of the organs of ani- 

 mals and plants, that the microscope has rendered so much service to 

 science. A whole creation of minute plants and animals, having dis- 

 tinct organs and performing varied functions, has been added to our 

 knowledge by the aid of the microscope. Let any one turn to a sys- 

 tematic account of the vegetable kingdom, and it will be seen that 

 there are whole families of plants recognized as members of that 

 kingdom whose existence can only be made out by this instrument. 

 Such are the diatoms, the desmids, and the volvoces. Amongst the 

 confervas, the fungi, the fuci, are whole tribes which could only have 

 been thus discovered. If we turn to the animal kingdom, a like series 

 of families is there found. The rhizopods, infusorial animalcules, 

 and other families are only known by the aid of the microscope, whilst 

 small forms of larger groups have been abundantly demonstrated. 

 The fascination of observing and describing new species has devel- 

 oped itself here, as in other departments of natural history, and hun- 

 dreds, nay, even thousands, of new species of microscopic plants and 

 animals have been discovered and described within these last 20 years. 



