330 Mr, Mcicleay on certain general Laws regulating [Nov. 



series of objects linked by affinity are drawn up in array, tlie 

 connexion of their extremes, that is, the formation of the circle, 

 becomes in that very moment, so far as I have observed, more 

 or less conspicuous. 



It follows, moreover, from admitting the existence of analot 

 gical relations, or, in other words, from laying down the paral- 

 lelism of groups in different series of affinity, that the number 

 of groups in these series must be the same. For were it other- 

 wise, as for instance, supposing three groups to exist in one 

 complete series, and four ni another, it js clear that the parallel- 

 ism could not exist. But if this parallelism be real, which has 

 been, as shown above, asserted independently of each other by 

 several naturalists acting in different branches of natural his- 

 tory, then the number of groups of the next lower order com- 

 posing a group of a given degree must be determinate. And if, 

 moreover, we accord to our author the accuracy of the following 

 rule, namely, " Nunquam negligendum, unumquodque regnum, 

 ordinem, genus, &,c. in systemate ut individuum esse sumen- 

 dum ;" — in other words, that class bears the same relation to 

 class which order does to order, and genus to genus ; then the 

 number of groups composing ani/ group of the next higher 

 degree must be determinate ; and it only remains for the natu- 

 ralist to discover from observation what this number is. 



That Nature has made use of determinate numbers in the con- 

 struction of vegetables has long been known empirically ; as for 

 instance, where botanists have found the typical number of parts 

 of fructification in the acotyledonous plants of Jussieuto be two, 

 that in monocotyledonous plants to be three, and that in dico- 

 tyledonous plants to be five, or multiples of these numbers. 

 Consequently the existence of a determinate number in the dis- 

 tribution of the plants themselves might have been argued 

 a priori. And in this manner indeed M. Fries appears to have 

 argued ; for it is tolerably clear that it was the consideration of 

 the foregoing rule, adopted by Nature in the structure of acoty- 

 ledonous plants, which induced him theoretically to assume four 

 as a multiple of two to be the determinate number in which 

 Fungi are grouped.* I say this, because he is obliged from ac- 

 tual observation to admit that of these four groups, one is exces- 

 sively capacious in comparison with the other three, and is 

 always to be divided into two. So that we may either, with 

 M. Fries, consider every group of Fungi as divisible into four, 

 of which the largest is to be reckoned as two, — a supposition 

 that would not only make two determinate numbers, but which, 

 from the binary groups not being alway analogous, will moreover 



• It ought],here to be observed, thatOcken had previously advanced the opinion that 

 four was the determinate number in natural distribution. This naturalist, however, 

 having in his Naiurgesihichtc fur schukn, lately published, in a great measure aban- 

 doned the number four for five, and tliat more especially in the ariimal kingdom, has 

 thus got into all the difficulties which necessarily attend tlie supposition of two determi- 

 nate numbers. 



