14,2 



EECEEATIVE SCIENCE. 



however, between the leaf and the whole 

 tree can only be traced in leaves whose veins 

 and stem are fully developed. In such, a 

 close analogy has been found between the 

 distribution of the branches on the trunk and 

 the position of the small vein upon the midrib. 

 It will be found in most cases, if not in all, 

 that the angle which the vein makes with 

 the midrib is the same as that between the 

 branch of the tree and the trunk. Mr. 

 M'Cosh has measured the angle of ramifica- 

 tion and the angle of venation in an immense 

 number of different trees and plants, and has 

 found the measurement to coincide. 



Those trees, which send out branches 

 from the root, or near the root, such as the 

 box, privet, holly, and oak, have leaves in the 

 same way without any, or with a very short, 

 footstalk ; whereas the leaves of those trees 

 which have a long unbranched trunk, like the 

 pear, cherry, sycamore, and chestnut, have, 

 generally, also a long footstalk. Hollyhocks, 

 rhubarb, mallow, and other low-branching 

 herbaceous plants, generally send out a group 

 of stems from the root, and, on examination, 

 you wiU. find that several midribs start from 

 the base of the leaf, and cause the leaf to 

 assume a rounded shape. In some trees, like 

 the beech and elm, the branches are almost 

 equally distributed throughout the trunk, 

 and in the same way the small veins are 

 usually distributed on the middle rib. Other 

 trees, like the sycamore and laburnum, send 

 off groups of branches at particular heights, 

 and the venation of the leaves follows the 

 same arrangement. The laburnum has trip- 

 let leaves, and a glance wUl show that the main 

 trunk is divided into three main branches. 



Thus an interesting subject of inquiry 



opens out before any of my readers who live 



in the country, and to such I hope that 



leaves, in future, will not be regarded merely 



as the summer ornaments of our woods and 



lanes, but that they wiU find, with Goethe, 



" All shapes are similar, yet all unlike, 

 I The chorus thus a hidden law reveals." 



GEEASE IN THE CABINET. 



Geease is a terrible destroyer of specimens 

 in the cabinet of an entomologist. Where 

 does it come from ? It is a kind of greasy 

 fluid, which exudes from the bodies of many 

 of our moths, especially of the Bombycidaj, 

 thence spreading over the wings, and event- 

 ually spoiling the specimen. Even keeping 

 the drawer continually stocked with camphor 

 will not prevent its appearance ; and I do 

 not know what will, but I know how to cure 

 it when it is there. 



The plan of operations may be described 

 as follows : — Eirst procure a bottle of benzole, 

 which may be got at any chemist's, and which 

 must be kept well stoppered when not used. 

 When about to operate, obtain a deep saucer, 

 or, better, an evaporating dish, in which place 

 your insect, then pour in carefully the ben- 

 zole till the specimen is entirely immersed ; 

 you need not be frightened at wetting it. 



It should be left thus for about five 

 minutes, the dish being kept covered up to 

 prevent waste by evaporation. At the end 

 of this time your insect may be taken out and 

 left till all the benzole has evaporated from 

 it, which will not take very long, when it wiU 

 be found to be in as perfect a condition as when 

 first set out ; with one advantage, that of not 

 being likely again to become greasy. 



This is not the only means of curing 

 grease, but I find that it far supersedes any 

 other, no especial process being afterwards 

 used to dry the specimen, which is so liable 

 to be detrimental to it; on the contrary, as 

 we have seen, it improves it rather than 

 causing any damage. 



The reason of this cure is, that benzole is 

 a solvent of grease ; thus, by leaving the in- 

 sect in it for a few minutes, the grease is 

 entirely dissolved out of it, in this way pre- 

 venting its future appearance. 



