COMPARATIVE ANATOMY. 84 



I ought however first of all to make a few remarks on the 

 subject of classification. Classification is of two kinds : — 

 natural and artificial. 



The first, the natural classification takes into consideration 

 the general characteristics of every part of the things to be 

 classified ; while the artificial classification looks only at the 

 variations and modifications of form, shape, colour, and 

 function of some particular organ or oi'gans. 



The student of botany will at once recognise an example of 

 this in what is called the Natural system, and the Linngean 

 system of the classification of flowers. 



In the natural system all the parts of the plant, the root, 

 the stem, the leaves, the flower, the fruit, are taken into con- 

 sideration. In the Linnsean, the number and arrangement of 

 the stamens and pistils are alone regarded. And the fact 

 that the Linnaean orders very nearly correspond with the 

 natural orders of plants, does not militate against the state- 

 ment that Linnaeus' classification was artificial, but only 

 shows the genius which prompted him to base his arrange- 

 ment on those organs of plants which have the greatest efl"ect 

 upon the variations of genus and species. 



Were our minds perfect, we should have no need of classi- 

 fication, but the horizon of man's finite understanding is so 

 bounded that it is only by dividing the picture by one limit 

 and another, and examining and photographing with our 

 mind, if I may so say, one portion after another, that we ever 

 can realize the beauty order and arrangement of that stupen- 

 dous whole, which Natural History lays before us ; and the 

 variations in the animal and vegetable kingdom may be, if we 

 will, the diff"erent expressions of the mind of the Creator, 

 while the links that unite them, the resemblances that exist 

 between one genus and another, one species and another^ and 

 the substantial unity of plan that pervades the whole, may, if 

 we will but see it so, exhibit to us the inviolable, yet un- 

 fathomable laws of that mind that never varies. 



But to turn to the immediate subject before us. 



Owen made an artificial classification of animals according 

 to the arrangement and character of their teeth, but was too 

 great a naturalist to overlook the consideration of their other 

 organs. It is, however, to the teeth of the mammalia that I pro- 

 pose to devote principally my attention this evening, although 



