the Natural Dislribiition of Insects and Fungi. 195 



The next work in whicli the distinction appeared was the 

 Memoircs dii Museum d'Hisfoire Naturellc ; in a part of whicli, 

 pubhshed in the antnmn of 1821, a paper was inserted by 

 M. DecandoUe on tlie natural family oi' Crnajenp. Here this 

 botanist states, that he finds it possible to express in a table all 

 the affinities existing in this family of jilants by what he terms 

 a double entree,- in other words, he supposes that there are 

 transversal affinities as well as direct ones, — a notion of the 

 reality however which appears to be much more confused than 

 that previously entertained by M. Agardh and explained as 

 above in his Botanical Aphorisms. 



In the same year (1821) likewise appeared the abovemen- 

 tioned work of M. Fries on Fungi, which is explicit on the 

 subject, and wherein the very same expressions of affinity and 

 analogy are used to designate these different relations, which 

 I had applietl to them two years before in treating of Lamel- 

 licorn Insects *. 



The theoretical difference between Affinity and Analogy may 

 be thus explained f: Suppose the existence of two jiarallel 

 series of animals, the corresponding points of which agree in 

 some one or two remarkable particulars of structure. Suppose 

 also, that the general conformation of the animals in each series 

 passes so gradually from one species to the other, as to render 

 any interruption of this transition almost imperceptible. We 

 shall thus have two very different relations, which must have 

 required an infinite degree of design before they could have 

 been made exactly to harmonize with each other. When, 

 therefore, two such parallel series can be shown in nature to 

 have each their general change of form gradual, or, in other 

 words, their relations of affinity uninterrupted by any thing 

 known ; when moreover the corresponding points in these two 

 series agree in some ojie or two remarkable circumstances, 

 there is every probability of our arrangement being correct. 

 It is quite inconceivable that the utmost human ingenuity could 

 make these two kinds of relation to tally with each other, had 



* I owe my acquaintance witlj tliese several works, as well as much in- 

 formation on points of which I should otherwise have been totally 

 ignorant, to tlie friendship of the consummate botanist, in whose possession 

 the iSanksian Library has been so worthily deposited. The second part of 

 the Ildivp Enfomo/ogir/e was publishctl in April 1H21. On the iJJth of the 

 followinj; month I first saw a copy of M. Dccandolle's j)aper, which was 

 not published till some weeks after, and in the course of last winter I first 

 raw A^'ardh's paper and the work of M. Kries on Fungi. If i\I. Fries bor- 

 rowed from his master Agartlh the idea of distinfjuishiii!; aflinity and ana- 

 logy, which is not improi)able, we must at least allow liini tiic merit of 

 having greatly improved this part of the theory. 



f See llfKV iLiilomi'liiirira-, p. ^Ui'-? ct srq. 



13 b 2 they 



