Jink, 191: 



KXOWLKDGK. 



237 



would be designated wool. It is one of the coninionplaces of 

 knowledge, that the hairs of most, and probably .ill, animals 

 differ very materially, according to the part of the body from 

 which they are taken : those from the back, for instance, being 

 usually coarser, while those from the under-parts are 

 invariably finer and softer, and it is an undoubted fact that 

 many of the latter have a strongly -marked, wool-like structure. 

 I know of no animal which exhibits this difference in the 

 character of the hairs from different parts of the body in so 

 striking a degree as the Hedgehog {Erinaccus ciiropaeiis), for 

 in that animal we have a gradation from stout spines to the 

 softest and finest hairs, and the histolo^'ical structure is 

 equally varied. There is, however, another animal, much 

 more familiar to us, which exhibits a similar wealth of variety 

 in the structure of the hairs from different parts of the body, 

 and the drawings of the hairs of the cow which are given as 

 illustrations (see Figures 262 and 263), will fully bear out this 

 contention. There we have gradation in a remarkable degree, 

 as there are large coarse hairs with strongly-marked medullary 

 cells, but with very slight indications of the overlapping 

 cortical cells, through others in which there is a gradu.al 

 diminution of the former structure and a corresponding 

 increase in the latter, until finally we arrive at those showing 

 the full characteristic structure of fine wool. From the 

 article " Wool "' in the " Encyclopaedia Britannica," I quote 

 the following, which states the case very succinctly — "' At what 

 point, indeed, it can be said that an animal fibre 

 ceases to be hair and becomes wool, it is impossible to 

 determine, because in every characteristic the one class 

 by imperceptible gradations merges into the other, so 

 that a continuous chain can be found from the finest 

 and softest merino to the rigid bristles of the wild boar." 

 It might be thought that the question had an academic interest 

 merely, but such is not the case : circumstances have been 

 brought to my notice which prove that it is also of some 

 commercial importance. Some time ago. one of our largest 

 manufacturers of felt submitted to me a sample for 

 microscopical examination. He had previously contracted to 

 supply to a German merchant, a ie\t free from -oi-ool. as the 

 tariff on all goods containing wool was absolutely prohibitive. 

 On arrival at the German port, it was examined by the experts 

 of the revenue authorities and refused admittance except on 

 the higher scale, on the ground that it contained wool. Then 

 ensued a deadlock, as the merchant refused to accept delivery 

 on what, to him, would have been prohibitive terms. It was a 

 sample of this felt which was submitted to me, after having 

 been sent to a Liverpool analyst, who suggested that it was 

 rather a n;atter for a microscopical specialist than for a 

 chemical analyst. It was submitted with an assurance that 

 no wool had been used in its manufacture. On examination, 

 it was composed, according to my view, of cow's hair and jute 

 with a small percentage of flax and wool. A report was given 

 to this effect, which, of course, was unsatisfactory, as one was 

 desired certifying to the toial absence of wool. Shortly after- 

 wards, another sample was submitted, the materials of which 

 had been mixed under the close personal supervision of the 

 head of the firm, who gave me his word of honour that 

 absolutely no wool had been used in the making of that 

 particular sample of felt. Again wool was found, roughly to 

 the e.xtent of about four or five per cent. This was inexplicable, 

 and I was assvired that there must have been a mistake some- 

 where, and a delicate hint was given that it could hardly have 

 occurred at their works. Separate samples of the materials 

 used in its manufacture were then asked for, and in the cow's 

 hair was found what was unhesitatingly pronounced to be 

 wool, and it was suggested that this was probably the source 

 of contamination and the explanation of the apparent 

 discrepancy. I was assured, however, that no admixture of 

 wool had taken place at their works, and that the considerably 

 higher price of wool (at least four times the price of cowhair) 

 was a sufficient guarantee for the honesty of the merchant from 

 whom the cowhair had been purchased. The matter could 

 hardly be allowed to rest here ; for. not to mention one's 

 reputation, which it was evident hkd suffered some diminution, 

 there was still no explanation forthcoming as to the undoubted 

 presence of wool, and my interest being by this time thoroughly 



aroused, I could not be content without following the matter 

 up until a solution of the difficulty should be arrived at. On 

 thinking the matter over, I determined to procure hairs from 

 different parts of the cow direct, with the satisfactory result 

 that from various parts, but especially from the flank, I was 

 both astonished and delighted to find that a considerable 

 proportion of the hairs had all the characteristics of sheep's 

 wool. To fortify my own dictum. I sent off specimens of this 

 wool-like cow's hair to several friends who are experienced 

 microscopists, one of whom undertakes chemical and micro- 

 scopical analyses for commercial men, and in every case it 

 was unhesitatingly pronounced to be wool. I am not aware 

 that the fact has been previously noted, and as the matter 

 appears now to have some commercial, as well as a scientific, 

 interest, this record may be considered as not without some 

 value. It is also gratifying to note that the German revenue 

 authorities, on the result of this modest piece of research being 

 submitted to them, have intimated that similar qualities of felt 

 will now be admitted free, if accompanied by an affidavit to 

 the effect that there has been no addition of sheep's wool. 

 As a result, several consignments have been made on this 

 undertaking, and although on one or two occasions there has 

 been some correspondence, the arrangement, I believe, still 

 continues. It would appear from this that our German 

 friends are now willing to consider that wool-like hairs, if not 

 from the sheep, are not wool, but they may readily be excused, 

 I think, if the practice gets commoner, or if our manufacturers 

 should utilise other animal hairs of a somewhat similar 

 character, if, for revenue purposes at all events, they should 

 revise their definition and insist that all wool-like hairs, from 



whatever source, are wool. t i- r 



J. E. Lord. 



THE PKEPAR.ATION OF SNAILS' TONGUES FOR 

 THE MICROSCOPE.— Every snail, and almost every 

 mollusc (except the Pelecypoda), bears upon its tongue a 

 number of symmetrically-arranged rows of teeth, with which 

 the food is rasped into a form convenient for ingestion. These 

 teeth are generally hook-like in form, whence they are called 

 unci. There is a central row, seen in the embryo of Physa 

 to be formed by the coalition of two side rows ; and the rows 

 which border upon the central row are generally of a different 

 type to the outer ones, so that there is a more or less clear 

 differentiation into admedian and external rows. It would have 

 been in accordance with the rules of anatomical nomenclature 

 to call the outer rows lateral, rather than external : but 

 unfortunately many authors have used the term lateral for the 

 admedians. In the case of Physa, which we have some 

 reason for calling a very primitive form, there are no 

 admedians, and all the unci are pectinated. This pectination 

 is less regular in Limnaeids ; in Succinea and the Helices it 

 undergoes a peculiar modification ; in the Arions (perhaps 

 derived from the Helicid stock) it is nearly lost; while it 

 undergoes a different kind of modification in Vitrina and 

 Liiiiax, and in Zonites only appears as a teratological rever- 

 sion. In Testacella it is not found at all. Indications are 

 thus supplied from which a classification of the Pulmonates 

 may be sketched out ; and into such a classification the other 

 anatomical characters appear to fit very well. It has been 

 objected that the nature of the food of the species determines 

 the type of radula. I believe that this may very well be the 

 case, but that the nature of the food is itself a most important 

 evolutionary factor ; that changes in this respect are likely to be 

 slow and not abrupt ; and that the whole of the organism, 

 including the reproductive and tegumentary organs, will have 

 reacted in harmony with such changes. According to this 

 view the main evolutionary changes have been brought about 

 by what is ultimately a chemical factor ; while there is much 

 reason for supposing that many useful and decorative modifica- 

 tions may have originated in sudden mutations, and it seems 

 likely that if we could more fully examine these mutations, 

 we might set them down as due to physical factors. In the 

 last resort no doubt it would be impossible to distinguish 

 between the chemical and the physical ; but still it appears a 

 plausible view that changes depending upon factors of a 

 smaller order should be slow and fundamental, while changes 

 depending upon larger and compound factors might be more 



