Relations of Organized Beings. 357 



which pervades the System of Nature*. These essential 

 agreements of parts consist rather in a similarity of organic 

 composition and of relative situation, than olform. A micro- 

 scopic examination of the primary tissue, or a chemical ana- 

 lysis of its substance, will often demonstrate the true affinities 

 of a structure when its external form would only mislead us. 

 And when we have proved an affinity to subsist between the 

 structures of two organic beings, we then apply the term to 

 the beings themselves, and say that an affinity subsists between 

 them, greater or less, according to the number and import- 

 ance of the organs in which such affinity is shown. Take for 

 example the long, straight weapon of offence in the Narwhal, 

 its general appearance is that of a horn, and such the vulgar 

 accordingly call it; but if we examine its organization and its 

 chemical composition, we find that both are utterly unlike 

 those of real horns, but correspond to the structure of teeth. 

 Further, if we examine the mode of its connexion with the 

 skull, we find that it is inserted into a socket like other teeth, 

 instead of being attached in the manner of horns, and we ac- 

 cordingly pronounce it to be not a horn but a tooth, deve- 

 loped for purposes of offence to an extraordinary extent. And 

 having thus shown that the weapon of the Narwhal has no 

 affinity to real horns, we no longer appeal to this structure in 

 proof of any affinity between the Narwhal and the truly horned 

 animals. Again, the Narwhal in its external form much re- 

 sembles a Fish ; but when we look to its nervous, circulatory, 

 and reproductive organizations, which rank much higher in 

 the scale of characters than external form, we find that it is 

 no Fish, but a true Mammal, agreeing in every essential point 

 with the warm-blooded quadrupeds of the land, to which its 

 affinities are real and direct. Similar instances of the dis- 

 cordance between outward form and real affinity might be 

 multiplied to a great extent; and it forms a constant employ- 

 ment for the scientific zoologist to distinguish real affinities 

 from apparent ones, and thus to refer every organized being 

 to its true position in the Natural System. 



It will thus be seen that every instance of asserted affinity 



* We may suppose, for instance, that it was a law of organic creation 

 that all Birds should have the anterior extremities modified into the form 

 of wings ; and in obedience with this law we find that there is no Bird 

 which is absolutely without wings, though there are several kinds in which 

 the wings are perfectly incapable of flight. Again, it is a law that Mam- 

 malia have neither more nor less than seven cervical vertebrae ; and we find 

 this law to hold good, without an exception, through the whole Class of 

 Mammals, from the slender-necked Giraffe to the Whale, which can hardly 

 be said to have any neck at all. The above, out of countless other exam- 

 ples, will show what is meant by laws of organization. 



