May i, iS65.j 



SCIEECE-GOSSIP. 



107 



change of colour in a negro, -who, from repeated 

 attacks of ague, was completely converted to a white 

 man, retaining the characteristic features and hair 

 of an Ethiopian. This change was accompanied 

 witli a great sensibility in the skin to the heat of the 

 sun and of fire. In the course of a few months the 

 natural colour returned, first in patches Avhich pre- 

 sented a singularly mottled appearance, and ulti- 

 mately the former black hue was thoroughly restored 

 to both skin and hair. 



Tf e have stated that the Pigment-cells are usually 

 polygonal ; bat this is not always the case, as is 

 illustrated in the frog, where the cells of the choroid 

 coat vary very much, and in its skin are curiously 

 stellate. The production or intensity of Pigment 

 would seem to be greatly influenced by the sun's 

 light and heat, a removal from such agencies speedily 

 enabling the skin to regain its former colour, as is 

 evidenced by the departure of freckles or browning 

 after afevv' weeks' retimifrom the exposure to them. 

 Little appears to be known of the chemistry of 

 animal Pigments, but their chief constituent is sup- 

 posed to be carbon. In a beautiful German prepa- 

 ration of a section of the human chin now before us, 

 not only are the hair-follicles and sudoriparous 

 glands plainly discernible, but also the Pigment- 

 cells in the stumps of hair, whicb have been cleverly 

 sliced by the skilfid. operator. An experienced 

 writer says that the skin must be macerated for 

 some days, when the epidermis can be removed and 

 examined with the uuder-surface uppermost. If it 

 be that of a negro, or any other dark-skinned race, 

 the Pigment-cells wiU be very distinctly seen by 

 transmitted light. But as negroes are not within 

 the reach of every microscopist, v^e must in this 

 country be content to purchase a good specimen, 

 readily mounted, from one of our well-known 

 mounters. The eye of the ox yields an excellent 

 object for examination, as the choroid membraue 

 can be easily put up in glycerine, and mounted in a 

 shallow cell. W. M. B. 



THE HAIB-WOIIM {Gordins aquatlcus). 

 By Wm. Helliek Baily, P.L.S., &c. 



WHILST taking a stroll with my family, in the 

 month of July, during last summer, along 

 the banks of the Dodder, at MiUtown, near Dublin, 

 at which time the water is very shallow in certain 

 parts of that river ; and as I am generally on the 

 look-out for objects of natural history, as well to 

 impart instruction to the young folks, as to add to my 

 own imperfect stock ; on looking into the water I 

 observed, at its margin, an extraordinary hair-like 

 creature swimming rapidly with graceful and sinuous 

 motion like a miniature eel. It immediately struck 

 me as being iV.Q Gordms aqi'.aticus, ov Hair-worm, 



although I had never seen one before. It was 

 easily captured ; and on renioving it from the water 

 evidently disliked the 

 change, becoming more 

 rigid, and when held 

 between the fingers ap- 

 pearing as if in much 

 distress, v/rithing about, 

 and, displaying great 

 elasticity, it made an 

 attempt to tie itself up 

 into a kind of true 

 Hair-worm T(fo',-^Lag«aikm).lover's knot, SUCh as 

 would perhaps, if it had 

 not uncoiled itself again, have puzzled even the 

 Davenport Brothers to unravel. 



Being provided with an open-mouth jar of water, 

 on returning home it was transferred to a glass 

 globe, in which were some other fresh-water objects. 

 Its restricted domains, or change of diet, did not, 

 however, appear to agree with it ; and after a few 

 days it died before I could observe any change in its 

 appearance. It is said in the early stage of its life 

 to live parasitically in insects. 



I obtained a second specimen from a moist place, 

 where there was little or no running water, on the 

 side of Carrick Mountain, near Eathdrum, in tlie 

 county of Wicklow. I was searching for Cambrian 

 fossils at the time, and on taking up a loose piece 

 of slate to examine it, found, instead of the Old- 

 Jumia, one of these remarkable filiform worms. I 

 kept this alive for some days, and on taking it to 

 our Natural History Society, a young medical friend, 

 who is doing good work in the investigation of 

 entozoa and parasitic animals, took a fancy to it, 

 and it was transferred to him. 



There is a popular notion amongst boys, which 

 probably arose from seeing this hair-lilie worm in 

 motion, that if a horse-hair is put into water, and 

 left there for a few days, it will turn into an eel. 



These worms, although placed with the Nema- 

 toidea, are distinguished from them by their struc- 

 ture, and especially by the absence of a posterior 

 aperture in the intestinal canal ; they are included 

 in the genus Gordiiis L., and are thus characterized : 

 —head rotund, mouth none, or not distinct, tail of 

 male bifid, and female rounded; its length is from 

 7 to 10 inches, and its thickness scarcely half a line. 

 It \i represented on the woodcut of the natural size, 

 and shows the power it has of coiling itself up. 



The feeling of our dignity and our power grows 

 strong when we say to ourselves, My being is not 

 objectless and in vain ; I am a necessary link in the 

 great chain, which, from the full development of 

 consciousness in the first man, reaches forward into 

 eternity. — Hyperion, 



