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degrees. Thus a genus may consist 

 of several species which approach 

 very near the type, and of which the 

 claim to a place with it is obvious ; 

 while there may be other species 

 which straggle farther from this cen- 

 tral knot, and which yet are clearly 

 more connected with it than with any 

 other. And even if there should be 

 some species of which the place is 

 dubious, and which appear to be 

 equally bound to two generic types, 

 it is easily seen that this would not 

 destroy the reality of the generic 

 groups, any more than the scattered 

 trees of the intervening plain prevent 

 our speaking intelligibly of the dis- 

 tinct forests of two separate hills. 



" The type-species of every genus, 

 the type-genus of every family, is, 

 then, one which possesses all the cha- 

 racters and properties of the genaxs 

 in a marked and prominent manner. 

 The type of the Rose family has al- 

 ternate stipulate leaves, wants the 

 albumen, has the ovules not erect, 

 has the stigmata simple ; and besides 

 these features, which distinguish it 

 from the exceptions or varieties of its 

 class, it has the features which make 

 it prominent in its class. It is one 

 of those which possess clearly several 

 leading attributes ; and thus, though 

 we cannot say of any one genus that 

 it must be the type of the family, or 

 of any one species that it must be the 

 type of the genus, we are still not 

 wholly to seek ; the t^^pe must be 

 connected by many affinities with 

 most of the others of its group ; it 

 must be near the centre of the crowd, 

 and not one of the stragglers." 



In this passage (the latter part of 

 which especially I cannot help noticing 

 as an admirable example of philo- 

 sophic style) Dr. Whewell has stated 

 very clearly and forcibly, but (I think) 

 without making all necessary distinc- 

 tions, one of the principles of a Natu- 

 ral Classification. What this principle 

 is, what are its limits, and in what 

 manner he seems to me to have over- 

 stepped them, will appear when we 

 have laid down another rule of Natu- 



ral Arrangement, which appears 

 me still more fundamental. 



§ 4. The reader is by this tim<ei 

 familiar with the general truth (which 

 I restate so often on account of the 

 great confusion in which it is com- 

 monly involved) that there are in 

 nature distinctions of Kind ; distinc- 

 tions not consisting in a given num- 

 ber of definite properties plus the 

 effects which follow from those pro- 

 perties, but running through the 

 whole nature, through the attributes 

 generally of the things so distin- 

 guished. Our knowledge of the pro- 

 perties of a kind is never complete. 

 We are always discovering, and ex- 

 pecting to discover, new ones. Where 

 the distinction between two classes of 

 things is not one of Kind, we expect 

 to find their properties alike, except 

 where there is some reason for then- 

 being different. On the contrary, 

 when the distinction is in Kind, wo 

 expect to find the properties different 

 unless there be some cause for their 

 being the same. All knowledge of a 

 Kind must be obtained by observation 

 and experiment upon the Kind itself ; 

 no inference respecting its properties 

 from the properties of things not con- 

 nected with it by Kind goes for more 

 than the sort of presumption usually 

 characterised as an analogy, and gene- 

 rally in one of its fainter degrees. 



Since the common properties of a 

 true Kind, and consequently the gene- 

 ral assertions which can be made re- 

 specting it, or which are certain to be 

 made hereafter as our knowledge ex- 

 tends, are indefinite and inexhaustible; 

 and since the very first principle of na- 

 tural classification isthatof forming the 

 classes so that the objects composing 

 each may have the greatest number 

 of properties in common ; this prin- 

 ciple prescribes that every such classi- 

 fication shall recognise and adopt into 

 itself all distinctions of Kind which 

 exist among the objects it professes 

 to classify. To pass over any dis- 

 tinctions of Kind, and substitute defi- 

 nite distinctions, which, however con- 



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