Dec. 1, 1868.] 



HARDWICKE'S SCIENC.E-GOSSIP. 



269 



and figures, differs widely and in a number of points 

 from either, and seems very persistent. I noticed 

 but one plant that appeared to lie between this and 

 the other varieties. In that specimen the calyx and 

 germen were hairy, the calyx-teeth reflexed (fig. 251), 



Fig. 252. Leat of Crategus Krystostyla. 



the style, when but one, incurved, and the nerves di- 

 verging — agreeing in these points with C. hyrtostyla. 

 It approached C. oxycanthoides in having (mostly) 2 

 styles, and in the general shape of the leaf, which was, 

 however, larger and of a darker green. This form 

 would appear to have considerable claims to be con- 

 sidered specifically distinct, more especially as there 

 is a biological difference of some importance between 

 it and the others ; viz., a difference in the time of 

 flowering. It is said by several botanists to flower 

 fourteen days earlier than the other forms. My own 



Fig. 253. Leaf of Crategus laciniata. 



experience shows a difference of at least a week. 

 As was noticed by Mr. Boswell Syme, "the margins 

 (of the leaves) are slightly convex from the base to 

 the apex of the first lobe " in C. oxyacanthoides, 

 while in the other forms they are " concave or 

 straight from the base to the apex of the first lobe." 

 This I find to be almost invariably the case. (Com- 

 pare fig. 248 with figs. 252 and 253.) 



How are we to regard these widely differing 

 forms ? As specifically distinct, or as mere varie- 

 ties? Mr. Hobkirk and continental botanists seem 

 inclined to look upon them as distinct species. How- 

 ever this question may be decided, there can, I think, 

 be no doubt that they are the result of variation, 

 modified by atavism, the variation resulting from 

 unknown causes acting slowly for a great length of 

 time. If secondary causes, then, are competent to 



produce varieties so widely differing from each 

 other as to render it doubtful whether they are not 

 specifically distinct, it is no violation of reason, and 

 analogy would bear out the result, to conclude that 

 species, and even genera, have been produced in the 

 same way. Some years ago it was generally believed 

 that " cataclysmal irregularity " was the method in 

 which geological phenomena had been wrought; 

 now, we have reason to believe, and with tolerable 

 certainty, that the operations of nature have ever 

 beeu characterized by the regularity with which she 

 performs her labours at the present day. So with 

 regard to the introduction and extinction of organ- 

 ized beings, it has been customary to regard them as 

 sudden, complete, and independent of natural laws ; 

 whereas, to use the words of an opponent of the 

 theory, " in the world around us we see nothing but 

 the activities of second causes ; and though reason 

 has yet failed to detect the mode in which new life- 

 forms are produced, faith may surely be allowed to 

 believe in their genetic connection [the Italics are 

 mine] by some continuously operating law." I find 

 myself totally unable to understand what is here 

 meant by & genetic connection produced by a continu- 

 ously operating luw, unless it alludes to some such 

 theory as the gradual evolution of species from 

 pre-existing life-forms. If we believe in a separate 

 and independent creation for each species, there 

 cannot be supposed to be any genetic connection 

 between them. The fact of the opponents of the 

 theory finding themselves compelled to use its 

 language, if not strong presumptive evidence in its 

 favour, is at least a proof of its utility in rendering 

 intelligible the highly complex yet harmonious 

 system of organic nature. 



John Hepworth. 

 St. Mary's Vale, Chatham. 



NOBERT'S TEST-PLATE. 



rj^HIS "marvel of art" is well described in a 

 -*- paper by Mr. Charles Stodder in the " American 

 Naturalist " for April, 1868. It consists of a series 

 of groups of parallel lines ruled on glass, each suc- 

 ceeding group being finer than the preceding one. 

 Different plates have a different number of groups, 

 ruled to different scales. One of the plates has 

 thirty groups of these parallel lines, in the coarsest 

 of which the lines are the one thousandth part of a 

 Paris line apart, and in the finest group the lines are 

 only one eight-thousandth part apart. Each group 

 or baud occupies about the two thousandth part of 

 an English inch in width ; and the whole thirty 

 groups occupy a space of little more than one 

 fiftieth of an inch. It is a difficult matter for the 

 mind to appreciate such minute divisions of space ; 

 but in order to form some idea of their minuteness 

 we are remined that "the average diameter of a 

 human hair is about the oue thousandth part of an 



