20 MICROSCOPIC ILLUSTRATIONS. 



and to claim for the microscope a high rank among" 

 optical instruments. 



The fact is, that since the modern improvements the 

 microscope has undergone, it is being brought to the 

 assistance, and is at the present time furthering the pro- 

 gress of almost every branch of natural science. To the 

 Geologist it may be said to be a new instrument. But what 

 has it not even now effected for him ? In his study of or- 

 ganic life and structure, it has unfolded to him the pre- 

 cise characters of divers animals and plants which inha- 

 bited and clothed our earth in ages which have long 

 passed away. Look at the discoveries of Agassiz on the 

 fossil creatures of the deep ! By a microscopic investi- 

 gation of such portions of them as have withstood the 

 destructive power of time, namely, their scaly covering, 

 he has been able so to group and class them, that the 

 characters and habits of the genera belonging to each dis- 

 tinct era are clearly demonstrated. A microscopic exa- 

 mination also of the testaceous remains of sundry Ento- 

 mostraceans found in slate-clay formations, now ele- 

 vated much above the level of the sea, prove them to 

 have been at some time or other imbedded in the waters. 

 And the Naturalist may even determine by his inspection 

 of the shell, whether the species were the inhabitants of 

 fresh or salt water, and consequently whether the strata 

 themselves were the indurated beds of the sea, or of some 

 river or lake. 



The most perfect animal remains which the microscope 

 has disclosed to us, are the various loricated Infusoria 



