14 INTRODUCTORY REMARKS. 



large quantity of water, in a ditch or pond, for example ; or if we cal- 

 culate, that according to many observers of the sea, and especially of 

 its phosphorescence, vast tracts of the ocean periodically exhibit a 

 similar development of masses of microscopic organised bodies ; even 

 if we assume much greater intervals ; we have numbers and relations of 

 creatures living on the earth, invisible to the naked eye, at the very 

 thought of which the mind is lost in wonder and admiration. It is the 

 microscope alone, which has enabled close observers of nature to 

 unveil such a world of her diminutive creation, just as it was the art of 

 making good telescopes which first opened to their view the boundless 

 variety and all the wonders of the starry firmament. 



2. But it is not here that the utility or interest of the microscope 

 ceases. To the botanist, the zoologist, the geologist, and the physi- 

 ologist it is equally valuable, equally indispensable. By its aid may we 

 examine the minute structure of the organs and tissues of which plants 

 and animals are made up, by it discover the links which bind the 

 vegetable to the animal kingdom, by it are we enabled to ascertain 

 the nature of the vegetation which decked the earth, long ere man 

 " moved, and breathed, and had his being ;" and by it may the anatomist 

 discover the structure in health, and the derangement from disease of 

 the various organs of the body. 



More recently the microscope has been brought to bear upon the 

 fossil animals, which are constantly being discovered in all parts of 

 the world. By a careful examination of sections of teeth and other 

 bones, the classification of the animals to which they belonged, as 

 made by geologists from other data, has in most instances been proved 

 to be correct. " In the hands of an Owen and a Mantell, the micro- 

 scope becomes an instrument of magic power ; by means of which, 

 from the inspection of a bone or a tooth, the colossal reptiles of the 

 ancient earth are revived in all the realily of life and being, and the 

 early formations of the egrth peopled with their former inhabitants 

 again." In medico legal enquiries, the microscope again comes to our 

 aid in detecting the murderer, and rendering him back the poison 

 grain for grain. Blood and other organic stains are by its means 

 readily detected when all other methods have failed. 



