October, 1912. 



KNOWLEDGE. 



399 



showing some measure of regenerative capacity. There have 

 been two recent revisions of the family, one by E. von Daday 

 (Revue Suisse Zool. XIX), and another bv .\. Hagmeier 

 (Zool.JahrbiicherXXXU). 



TOOTH-WORMS. — In some parts of Hungary there is a 

 vulgar belief that b.id toothache is due to minute worms. By 

 their writhing and gnawing they produce abscesses in the gum, 

 and one of the popular cures is to fumigate the mouth very 

 thoroughly so that the worms are driven out from their hiding- 

 places. The thorough fumigation of the mouth is a wide- 

 spread habit all over the world, but the tooth -worm myth is 

 rare. It may have had an origin, one might suppose, in the 

 very rare occurrence of fly-larvae (Sarcnpliaga wohlfahrti) 

 in bad buccal abscesses, but Professor Karol Sajo's examina- 

 tion of the alleged "tooth-worms." which the Hungarian 

 sutferers are willing to demonstrate on the spot, has shown 

 that they are the funicles of the seeAf,o{ HyoscyaDius, which 

 are used, we suppose, as an anodyne. 



FRESHWATER STING-RAYS OF THE GANGES.— 

 It has been known since the beginning of the nineteenth 

 century that rays occur high up the Ganges, but considerable 

 doubt has existed as to the species. This has been cleared 

 up by B. L. Chaudhnri, who shows that there are at least two 

 freshwater Batoids in the Ganges, viz.. Try-on fluviatilis and 

 Hypolnplius sephen. These species are not only found one 

 thousand miles above tidal influence, but also breed freely in 

 fresh water. 



FISHES AND MALARIA.— In 1905, it was pointed out 

 that the Barbadoes were remarkably free from malaria, and 

 the reason suggested for this was that the mosquito larvae 



(which elsewhere grow up into distributors of the malaria 

 organism) were devoured by a small fish, popularly known as 

 " iniUions," very abundant in all the streams and pools. 

 Captain R. B. Seymour Sewell and B. L. Chaudhnri have 

 recently shown that there are numerous (they describe eleven 

 species) Indian fishes which are of proved utility as mosquito- 

 destroyers. Thus we have another thread in the web of life — 

 '■ fishes may be a very import.int agent in regulating and 

 diminishing the degree of [iialarial infection in any given 

 district." 



ERI SILK. — Messrs. H. Maxwell-Lefroy and C. C. Ghosh 

 give an account of Eri silk, which is grown in Assam for local 

 use, and may perhaps have a big future before it. Eri silk 

 cannot be reeled, for the cocoon is in layers, not in a continuous 

 thread. The moth (Attacus ricini) can push its way out 

 without softening or cutting the fibres, and may be allowed to 

 mature within the cocoon and emerge. The fibre can be spun 

 as cotton is, and the yarn can be woven quite readily. The 

 resulting silk cloth ("Endi") is the most durable cloth known 

 in India, and takes dye well. The silkworms live on Castor 

 leaves 



PEARLS AND PARASITES.— After a searching inquiry. 

 H. Lyster Jameson coniiis to the conclusion that there is 

 insufticient evidence for the theory that the pearls of the 

 Ceylon Pearl Oyster are due to the larvae of the tapeworm 

 Tetrarhynchus unionifactor. It appears probable that the 

 simultaneous presence of pearls and tapeworms in the Ceylon 

 Pearl Oyster is a case of two parallel diseases, comparable 

 to the case of a dog infected simultaneously with tapeworms 

 and mange. According to Jameson, pearls arise round nuclei 

 of some variety of shell-substance formed when the normal 

 rhythm of secretion is disturbed. 



SOLAR DISTURBANCES DURING AUGUST, 1912. 

 By FR.\NK C. DENNETT. 



August was remarkable for its lack of clear sky, but during 

 the month only two days were entirely missed, the 15th 

 and the 23rd. Spots were only seen on four days, the 11th, 

 12th, 21st and 2Sth, and on ten others only faculae were visible, 

 leaving fifteen upon which the disc appeared quite free from 

 disturbance. At noon on August the 1st the longitude of the 

 central meridian was 224"" 42'. 



No. 12. — A minute group of pores only seen on the evening 

 of the 11th and on the morning of the 12th, the true position 

 having to be estimated rather than measured. 



No. 13. — A penumbraless pore, bright edged, with its 

 eastern edge somewhat rough, and on its western side the 

 surface showed traces of minute black specks, but it only 

 lasted one day, the 21st. 



No. 14. — .\ group of minute pores observed with difficulty 

 on the 28th in the place seen on the previous day to be 

 occupied by a faculic area. The position has been given by 

 estimation, as measures were impossible. It appears to have 



been situated directly south of the place in which No. 11 had 

 been seen in July. 



Faculic areas were observed on .\ugust 2nd and 3rd about 

 longitude 242", and south latitude 40". On the 7th, near the 

 western limb. On the 10th and 11th east toward south-east, 

 in longitudes 16° and 34° and latitudes 9° and 4° to 8° south 

 respectively. On the 19th, within the eastern hmb a little 

 south, in longitude 276° and latitude 12°. On the 21st a 

 faculic ridge from 9° to 11° south, near the western limb, 

 longitude 25"; also a knot at 247", 10° south, and another in 

 very high southern latitudes near the central meridian. On 

 the 25th a double knot of faculae was approaching the south- 

 western limb, situated longitude 339 , and south latitude 19° 

 to 22'. And on the 27th, some 30° within the eastern limb, 

 longitude 179% south latitude 10 , the faculic disturbance was 

 seen which heralded the group No. 14. 



Our chart is constructed from the combined observations of 

 Messrs. J. McHarg, A. .\. Buss, C. Frooms, and the writer. 



DAY OF AUGUST, 191 2. 



10 JO JO +0 50 60 



90 100 110 <uj eo M !» »<; i7o leo ;9o m 2(1 220 :« ^«) jso jm 27o 



290 300 510 320 3X M 350 3(j0 



