140 



NATURE 



[June 9, 1898 



are given— one representing the absorption of oxygen by the 

 materials as tested, and the other the absorption calculated for 

 "pure gutta," since here also it is mainly this constituent by 

 which the absorption takes place. 



The appendix to the lectures, given in the reprint, contains the 

 results of a complete chemical analysis of the identical speci- 

 mens of gutta percha used for the determination of the specific 

 gravity and the experiments on the absorption of water and 

 oxygen. 



Experiments were also shown to demonstrate the remarkable 

 difference in the behaviour of gutta percha and caoutchouc to- 

 wards ozone, thin tissue of the former resisting the action of 

 strongly ozonised oxygen for a considerable time, whereas a 

 caoutchouc membrane was pierced by a jet of this gas impinging 

 on it in a few moments. The lecturer also spoke of the applica- 

 tions of gutta percha hardened by extraction of the resin accord- 

 ing to his process, proposing it for the use of boats for the 

 arctic regions, on account of its considerably greater strength 

 than that of ordinary gutta percha at very low temperatures, 

 which was demonstrated by experiments. 



He also showed that the elasticity of golf balls, as shown by 

 the height of rebound when allowed to drop on a stone slab, 

 depended almost entirely on the percentage of resin in the gutta 



doubtless be of interest. The skull, that of a Hartebeest, was 

 exhibited at the Linnean Society on January 20 last, and is 

 the original of the sketch ; the cocoons are cylindrical and 

 closed at the outer end like the fingers of a glove, extremely 

 tough and composed of a dark grey felt substance, evidently the 

 comminuted fibres of horn, the largest being about three 

 inches in length ; these cocoons are formed by the horn-feeding 

 larvoe of the moth known as the Tinea vastel/a, and the following 

 is a description of the insect :— Very pale gilded ochraceous 

 shining. Head ochraceous and tufted above, palpi porrect, 

 pubescent, extending a little beyond the front, much shorter 

 than the breadth of the head, third joint lanceolate, much shorter 

 than the second. Abdomen extending much beyond the hind 

 wings. Legs rather long, hind tibiae thinly fringed. Wings long, 

 narrow, fringe rather long, fore wings slightly acute, exterior 

 border very oblique, under side and hind wings purplish cinereous, 

 excepting the fringe. Length of the body seven lines, of the 

 wings sixteen lines. 



A very interesting point with regard to the habits of this 

 insect, which has not yet been cleared up, but upon which I hope 

 to be able to throw some light, through the observations of 



t « a 8 M I* 14 ■• IS 

 Weeks 



Genuine 



Soondie 

 White 



» a4«Sioiai4'ie>a 

 Weeks 



Mixed ^—~^—~^— 

 Leaves --^--^-- 

 Balata — x — x — x 



Fig. 4.— Absorption of oxygen by different " classes " of gutta percha. 

 (Two spheres, each 16 mm. diam.) 



percha of which they are made ; and consequently the treatment 

 by the hardening process is now invariably resorted to, except in 

 the case of gutta percha obtained from leaves by chemical pre- 

 cipitation processes, which consists almost entirely of pure gutta, 

 as has been already mentioned. 



HORN-FEEDING LARV/E. 

 COME few months ago I received a consignment of skulls of 

 •^ antelopes from West Africa, the specimens having been 

 shot by the late Lieut. R. H. McCorquodale, 3rd Dragoon 

 Guards, and on opening the cases I was much struck by the 

 appearance of the horns ; all, without exception, were infested by 

 singular thin finger-like protuberances which seemed to grow 

 from the horn, leading me at a first impression to the immediate 

 conclusion that they were some species of fungi ; on a nearer 

 inspection I found them to be cocoons, and not having seen 

 anything like them before I looked into what literature I could 

 find on the subject. 



As it is, generally speaking, only travellers, or those in touch 

 with travellers, who have the opportunity of seeing the actual 

 cocoons on the horns, a sketch and a few salient points will 



Cocoons i natural 



Skull and horns \ natural size. 



NO 1493, VOL. 58] 



officers now serving in Africa, is, that it has been asserted to 

 feed on the horns of living animals ; and in support of this I 

 will quote the following : — " Dr. Fitzgibbon many years ago 

 while in Gambia stated he was surprised at finding grubs 

 enclosed in cases, which projected from the horns of animals 

 freshly killed, the blood not being yet dry, the carcases of the 

 animals being exhibited in the market place." This statement 

 is recorded in vol. i. of the Proceedings of the Dublin Zool. 

 Soc. "In contradiction, Lieut. -Colonel Wenman Coke said he 

 had shot large numbers of various species of horned animals in 

 South Africa, but that he had never seen the horn of a living 

 animal perforated by one of these larvae, although he had seen 

 many dead horns infested with them. Colonel Coke is most 

 confident that the larvae never attacks a living animal ; he says 

 that had this been the case it could not have escaped his observ- 

 ation ; Mr. Truman concurs in expressing great doubt as to 

 the correctness of the theory that the larvae feed on the horns 

 of living animals." We have the strong evidence of Dr. Fitz- 

 gibbon, and might argue that, as the fibrous substance of the 

 horn undergoes little or no change at the death of the animal, 

 there seems no reason why the moth should not deposit its eggs 



