Jan. 1, 1S68.] 



HARDWICKE'S SCIENCE-GOSSIP. 



9 



To be applied with a camel-hair brush. 



No collector in a tropical climate need be in- 

 formed of the destruction caused by the active little 

 black ant, which infests every house, even when 

 the object is placed on a table with its legs sur- 

 rounded by water ; for I have known these vermin, 

 in the course of a night, make a bridge of their 

 little bodies across a couple of inches of water, and 

 make a clean sweep of the contents of the table ; 

 but with this preservative, in which my sheets of 

 cork had been well saturated, and afterwards dried, 

 I never knew ants approach any object when on the 

 cork, even when lying on the ground. 



Aberdeen. R. Dyce, M.D. 



HOW BIRDS AND INSECTS ELY. 



A COMMON quill pen affords as beautiful and 

 -^-*- complete an example of contrivance as can 

 be found in the whole range of creation. The wing 

 of which the' quill pen once formed a portion was 

 given to the bird for the purpose of flight ; in other 

 words, by raising and depressing the feathers com- 

 posing the wing, the bird was to support itself in 

 the air. But to a human workman an enormous 

 difficulty would have occurred at the very outset of 

 his undertaking. The feather, both for the sake 

 of lightness, and to allow of the air passing through 

 it unimpeded, must be made as it is ; viz., of a 

 central shaft with innumerable distinct laminae pro- 

 jecting from it on each side. The problem to be 

 solved was this, " How shall these lamina? be held 

 together, so that they shall not be forced asunder 

 by the action of the air during the downward stroke 

 of the wing " ? Now, see the beautiful piece of 

 contrivance, the admirable example of design, to 

 which I referred just now. If the reader has the 

 good fortune to possess a microscope, or even a 

 lens of a tolerably high power, he has only to cut 

 or tear off a small piece of the feather — in fact, a 

 few of the projecting lamina?— lay them on the stage 

 plate, and gently force* them asunder, and the mys- 

 terious secret will be revealed at once. He will see 

 that one side of each laminae is crowded with 

 minute hooks: and a further study of the object 

 will show him that these hooks are intended, and 

 indeed do naturally fasten themselves on to the 

 edge of the next-lying lamina. Thus the rows of 

 lamina? on each side of the shaft are firmly bound 

 together, the whole forming one continuous feather, 

 an instrument of flight, which is unrivalled for 

 lightness and pliancy, and at the same time, through 

 the agency of these almost invisible booklets, per- 

 fectly stiff and strong. I never had the patience to 

 calculate their number, but the total amount in 

 a single quill pen must be something astounding ! 



I need perhaps scarcely add, that no such con- 

 trivance is to be found in the wings of birds not 

 destined for flight : they are wanting altogether in 



the apteryx, emeu, cassowary, ostrich, &c. Indeed, 

 it is in a great measure the absence of these hooks 

 which renders the feathers of the latter bird, and 

 of the bird of paradise, so peculiarly lovely and so 

 well fitted for purposes of ornamentation. In these, 

 each lamina waves gracefully in the air, completely 

 unconnected with its neighbour, and unrestrained 

 by the iron grasp of the tiny instruments which so 

 materially aid most of the feathered tribe in their 

 flight. 



To find any similar structure outside the ornitho- 

 logical world, we must make a long stride across 

 the fishes and reptiles to the insects ; past the 

 beetles and moths (these, by the way, are sometimes 

 allowed a single hook), and so on to the hymenoptera 

 —the wasps, bees, and ants. In all these we once 

 more come across this striking example of design in 

 full perfection. 



A careful examination of the organs of flight in a 

 bee or wasp under the microscope discloses the fact, 

 that the anterior margin of the lower wing on each 

 side of the body is lined with a series of hard horny 

 hooks, precisely the same in principle with those on 

 the bird's feather, though very different in ap- 

 pearance. In point of fact, the insect's booklet is 

 much more perfect and, so to speak, better made 

 than the bird's. Instead of being a mere strip from 

 the membrane of the wing itself, it is composed of a 

 distinct substance — chitine — the same substance 

 which forms the stiff hard claws with which the feet 

 of insects are terminated, and to which indeed these 

 booklets bear no little resemblance. The shape 

 varies, too, much more than in birds. They are not 

 all of the simplest form, like a fish-hook without its 

 barb, but there is a regular gradation, from the stiff 

 booklet at the base of the wing, with its gracefully 

 curved end, to the simple straight hair at the other 

 end of the line. 



Now, whence arises this extraordinary difference ? 

 Whence comes it, in fact, that the inferior animal 

 (the insect) is gifted with a more perfect instrument 

 than its more highly-organized relative, the bird ? 

 The answer is simple. Each individual booklet in 

 the bird's wing is comparatively weak, because, from 

 their immense number, and from the peculiar orga- 

 nization of the wing itself, made up of innumerable 

 lesser parts, the loss of a single booklet is of very 

 little consequence. A bird might lose a thousand 

 of its booklets, and doubtless often does, from the 

 scattering shot of an awkward sportsman, and be 

 none the worse for the accident ; but the loss of 

 half-a-dozen only would seriously impede the func- 

 tions of an insect, and prevent it from holding its 

 place in nature. 



Consequently, each particular booklet is made as 

 perfect as possible. Looking at the matter from 

 this point of view, we are reminded of an analogous 

 instance in the case of " stings." The wasp has a 

 single sting, as stiff and hard to break as a needle, 



