196 NATURE AND LIFE. 



but to effect the composition of albuminous substances, in 

 order to give us the complete mastery of the processes which 

 Nature follows in her elaboration of immediate principles. 

 That gift of making its object a reality, which is the peculiar 

 privilege of chemistry, is also one of the strongest argu- 

 ments to bring in proof of the absoluteness of those laws 

 which we ascertain respecting the system of forces external 

 to us. 



Linnaeus, whose mind was remarkably analytical and 

 classifying, not only arranged vegetables and animals in 

 order, but also classified diseases, and even odors. He 

 refers the latter to seven classes : aromatic odors, such 

 as that of laurel-leaves ; fragrant, like those of lilies and 

 jasmine ; ambrosial, such as amber, musk, etc. ; garlicky, 

 like that of garlic ; fetid odors, like those of the goat, the 

 orage, and others; disgusting odors, as those of many 

 plants of the solaneae order; and, last of all, nauseous 

 odors. The terms of Linnaeus have generally become cur- 

 rent in language, but we understand, of course, that their 

 value is merely conventional. As we have said before, 

 there is no standard for the comparison of odors. We can 

 only describe them by making comparisons between them, 

 according to the degrees of resemblance existing between 

 the impressions with which they affect our olfactory mem- 

 brane. They have no qualities capable of being rigorous- 

 ly defined. This is the reason why it is impossible to give 

 them any natural classification. 



III. 



The sensations produced by smells are perceived and 

 judged of in a great variety of ways, though with less dif- 

 ference than prevails as to tastes. " I have seen a man," 

 says Montaigne, " fly from the smell of apples quicker than 

 from a cannonade." The instance he alludes to in this 

 passage is that of Quercet, Francis I.'s secretary, who rose 



