SCIENCE-GOSSIP. 



317 



Luminosity in Animals. — One of the most 

 curious phenomena of life is that faculty possessed 

 by certain organisms of radiating into space, as 

 luminous vibrations, a portion of the energy that 

 animates them. In this respect insects take the 

 first place, though this same photogenic power 

 is found both in higher and lower orders of life. 

 Professor Dubois has devoted much time to the 

 study of the origin of physiological light, and he 

 tells us that the luminosity of most of the so-called 

 " luminous earths" is due to the presence of minute 

 organisms, of which Lipura noctiluca is an instance. 

 Fig. 1, the glowworm {Lampyra noctiluca) is a 

 well-known example among the more highly 

 organized insects. Before fecundation the photo- 

 genic property appears in the egg of the glow- 

 worm, even 

 while it is 

 contained in 

 the ovary. At 

 the moment 

 of hatching, 

 in the larva 

 of the first 

 stage, the 

 luminous 

 appearance 

 shows itself 

 in the form 

 of two small, 

 yellow ovoid 

 bodies, situ- 

 ated on the 

 sides of the 

 penultimate 

 ring, fig. 2. 

 In the glow- 

 worms the 

 light -produc- 

 ing power is 

 not limited to 

 the ovaries, 

 as, when 

 moulting, the 

 entire hypo- 

 derm shows a 

 feeble phos- 

 phorescence. 

 Fig. 3 shows 

 the location of 

 the photo- 

 genic organ 

 in the male 

 Lampyra. 



" Modern Microscopy " is the title of a very 

 useful treatise on the microscope and microscopical 

 technique, written by M. J. Cross and Martin J. 

 Cole, and published in London by Bailliere Tindall 

 and Cox. The main object of the book is to afford 

 such information and advice as will assist the 

 novice in choosing his microscope and accessories, 

 and direct him in his initial acquaintance with the 

 way to use it. It is not the novice only that will 

 find this book of service. The second part will be 

 found to be indispensable to the advanced worker 

 by reason of the wealth of practical suggestions 

 that it contains relating to laboratory work. Mr. 

 Martin J. Cole treats this portion of his subject in 

 a masterly manner, and in a course of fourteen 

 lessons he takes the student through the various 

 methods of preparing, staining, hardening and 

 mounting which he himself has adopted in his ripe 

 experience both as a worker and as a teacher. It 

 is a book that every microscopist should possess. 



Fig. 3.— Section of the terminal portion 

 of a male Lampyra noctiluca. 0, Pho- 

 togenic organ. 



Some Eastern Parasites. — The genus Filaria, 

 that of the threadworms, has been credited at 

 different times, according to Dr. G. Archie Stock- 

 well, with more than a score of species, many of 

 which are due to error, and about all of the others 

 there is much to learn. The most notable are the 

 Filaria sanguinis-hominis, the F. guinense, and the 

 F. lota or F. conjunctiva. The first-named, com- 

 paratively common in the Orient, reaches a length 

 of three-fourths of an inch or more, and infests the 

 circulation, being often unnoticed, but in numbers 

 checking the flow of lymph and producing painful 

 glandular enlargements, abscesses, etc. The Guinea 

 worm, found not only in Africa but in the Philip- 

 pines and even in the West Indies, resembles a 

 horse-hair, often three or four feet long, penetrating 



the muscles 

 and some- 

 times causing 

 dangerous ul- 

 cerations. 

 The F. lota, 

 found only 

 under the 

 conj unctiva 

 of the eye, is 

 about an 

 inch long, 

 and, though 

 an African 

 worm, is not 

 confined to 

 negroes, as 

 was formerly 

 supposed. A 

 white victim, 

 an English- 

 woman, dis- 

 covered a 

 Filaria in one 

 eye through a 

 pricking sen- 

 sation, and 

 afterwards 

 noticed it 

 wanderi n g 

 over the eye 

 beneath the 

 conj unctiva, 

 raising aridge 

 as it passed, 

 and even 

 crossing the 

 nose to the 

 other eye, remaining always invisible during cold 

 weather after the lady's return to England. It 

 was finally removed from the left eye, much to the 

 patient's relief. 



Preservation of Crystals. — To prevent the 

 deliquescence of crystalline bodies in microscopical 

 mounts they should be covered with a drop of 

 castor oil and subjected to a gentle heat. If the 

 cover-glass be then put on and sealed down the 

 crystals will last for years. 



Unmounted Material. — Mr. W. West, of 

 15, Horton Lane, Bradford, Yorks, issues a new 

 catalogue of unmounted material prepared by 

 Mons. S. Louis, for whom Mr. West is the agent in 

 Britain. These objects include beautifully cleaned 

 diatoms from many parts of the world, sections of 

 woods, micro-fungi and rich foraminiferous sands, 

 etc. Microscopists will find this list worth ex- 

 amination. 



Fig. 2. — Larva of Lampyra noctiluca 

 in its first stage : a a', ultimate and 

 penultimate segments. On the 

 right the luminous organs can be 

 seen, showing through. (Magni- 

 fied 65 diameters.) 



