Mr. T. H. Huxley un the Method of Paleontology. 45 



A simple illustnitiou or two, however, will show that the laws 

 of physiological correlation alone are wholly incompetent to fur- 

 nish such guidance. Suppose I find the jaw of a vertebrate ani- 

 mal with sharp cutting teeth imbedded in it, how far will phy- 

 siology help me to determine the precise nature of the animal to 

 which it belonged ? The sharpness of the teeth may lead me to 

 guess that they were used for cutting some soft substance. The 

 shape of the articular condyle and that of the processes for mus- 

 cular attachment may equally render probable the direction and 

 force of its ordinary movements ; but as to the rest of the or- 

 ganism, whether the teeth were for cutting up fish, flesh, fowl, 

 or carrion, whether the creature itself was piscine or reptilian or 

 mammalian, — on all these points no amount of mere physiological 

 reasoning will help me. Nay, how do I know it is a vertebrate 

 jaw at all ? that it is vertebrate bone and tooth substance ? For 

 anything physiology teaches me to the contrary. Invertebrate 

 animals might develope osseous and dentinal tissue, and might 

 possess appendages having the form of vertebrate jaws. 



Every naturalist knows that Invertebrate animals do not thus 

 mimic the Vertebrata, and he believes that they never have and 

 never will do so ; but his confidence is based, not on any physiolo- 

 gical reasoning as to the impossibility of such a proceeding, but 

 on his simple experience that it never does occur. He rests not on 

 a deduction from the laws of physiological correlation, but on the 

 morphological law that no Invertebrate animal ever possesses an 

 organ having the form and structure displayed by the jaw in 

 question. And this law is an empirical one ; no further reason 

 for it can be given than for the law of gravitation. The 

 whole object of morphology is to ascertain ivhat structural pecu- 

 liarities invariably coexist with one another : why these struc- 

 tural peculiarities coexist is a question with which it does not 

 necessarily concern itself, and so far as the mere restorations of 

 the palaeontologist are concerned, it is a wholly irrelevant question. 

 The empirical laws of morphology supply all that the palaeon- 

 tologist requires for this object. 



Let us imagine that all existing animals had perished, but that 

 their dead forms were gathered together and submitted to the 

 investigation of some intelligent being from whom the know- 

 ledge that they had ever lived was concealed. He would of 

 course remain entirely ignorant of physiology and all its laws. 

 Life, if he were acquainted before only with physical and chemical 

 phsenomena, would be an inconceivability, and the conception of 

 adaptation to purpose, of physiological correlation, would fail to 

 suggest itself whei-e nothing was known of actions or functions. 



Nevertheless, by the careful comparison of one form with 

 another, he would see that in one set of specimens certain struc- 



