Mr Glover on Forms of Indtiction. 129 



instances which may not have been wholly examined, by means of 

 an investigation of other instances apparently only analogous. 

 Thus, let us suppose, that a definition of the term animal wei'c 

 formed, stating that an animal is a being possessing sensation 

 and voluntary motion ; and that it could be found, by a com- 

 parison of some of the different grades of animalized being, that 

 just in the ratio of the development of nervous matter, was the 

 state of those functions, in an increasing or a decreasing ratio ; 

 and that where this nervous matter exists (as in the genus Echi- 

 nus and the sub-kingdom Acrita, generally banished by natu- 

 ralists of the present day from the animal kingdom) not in 

 the form of filaments connected with a common centre, the 

 functions are wanting ; would we not be entitled to conclude, 

 that, in all animals, the development of a nervous matter in 

 the filamentous and radiated form, bears an exact ratio to the 

 aforementioned functions? If we do not admit that a few 

 instances can be taken as specimens of a class, containing indi- 

 viduals apparently dissimilar, then, indeed, the mode in which 

 the mind arrives at laws in physical investigation is often incom- 

 patible with logical propriety, — a proposition truly monstrous ! 

 But it will doubtless be asked, in what way a conviction can 

 be got of the essential nature of connexions investigated in Na- 

 ture, when, in the properties themselves, no reason for this es- 

 sentiality can be detected. Our answer is the admitted apho- 

 rism, that we are compelled, by the very constitution of our 

 minds, to take the constancy and invariableness of relations ob- 

 served among properties, as warrants of the essentiality of the 

 order of relationship. Could the true principles of essentiality, — 

 the FOEMS of Bacon and of Aristotle — be discovered, we should 

 then have reasons from which it might be possible to know the 

 extent to which certain relations, observed in a single instance, 

 could reach throughout Nature ; and our knowledge of the 

 external world would be a perfect knowledge, so far as it should 

 go. But so long as those principles remain undiscovered, the 

 logic of physics must owe its coincidence with fact to an ad- 

 mission, on empirical grounds, of the existence of an essential 

 series of phenomena, where there is but the evidence of their 

 observed order being constant. We have said, however, that 



VOL. XXIII. NO. XLV. — JULY 1837. I 



