No. 4075 December 6, 1947 NATURE 799 At its maximum development the endoccele extends immersion for I5 min. in 1 per cent caustic soda. for one third of the length of the egg, and at this If this were prevented for 24 hours by anchoring stage organ-rudiments appear. Well-defined regions the fibre in the caustic soda at its original length, it of hypoblast lie one on either side of the endoccele will not assume fine coils when, afterwards, the ends (L.Hp) and one on the ventral side. The epiblast are moved closer together, but it goes into a few partially segregates into a region anterior to the irregular large coils. endoccele, another on its antero-ventral aspect and Large. irregular coils resulted from using the a third ventral to the ventral hypoblastic band. The following solutions at 20° C. : I or 3 per cent pot• three hypoblastic bands extend posteriorly to form assium cyanide, 1 per cent sodium thioglycollate, and the reproductive organs, while anteriorly they de• 0·125 and 0·33 per cent sodium sulphide and 0·88 velop into excretory system rudiments. The ventral S.G. ammonium hydroxide. 1 per cent potassium epiblastic band forms the body-wall by the migration hydroxide gave results similar to I per cent sodium of its cells through the yolk to the periphery of the hydroxide, but barium hydroxide was not effective egg. The anterior epiblastic region is the nervous in this respect. system rudiment and the antero-ventral region is the Merino wool in 1 per cent sodium sulphide (an• pharyngeal rudiment. hydrous salt) at 20° C. was then studied under similar The endoccele now undergoes marked reduction conditions. In this solution the fibres immediately in size and the pharynx develops a large lumen. straighten out and remain straight for 1 min. They These two cavities unite and the endoccele thus assume large coils within 3 min., and are very closely becomes the cesophagus. Cells from the wall of the coiled in 6 min. (if transferred to water at this stage cesophagus proliferate and form an intestinal wall these coils disappear but reappear when again im• enclosing most of the remaining yolk material. At mersed in the sulphide solution), and IO min. after hatching, all internal organs have developed into a immersion they again straighten. The fibres once functional state except the reproductive systems. more wind up into very fine coils I5 min. after A fuller account is being published elsewhere. immersion and may then disintegrate. The lengths RoY A. HARRISON of six Leicester fibres, which at no stage have been Zoology Department, under tension, had increased finally in 1 per cent Victoria University College, sodium sulphide between 33 and 56 per cent, aver• Wellington, New Zealand. aging 47 per cent. Aug. 6. The action of 1 per cent caustic soda may be due to a high pH, and the further reactions of 1 per cent sodium sulphide may be due to subsequent reduction. Coiling of Wool Induced by Certain Treatment of fibres with 1 per cent caustic soda for Reagents 15 min., followed by a wash in water which causes them to uncoil, and subsequent immersion in 1 per DURING some investigations regarding twist in cent sodium sulphide resulted in the characteristic wool, some observations worth describing were made, coiling, straightening and further coiling that has though no explanation can be offered. been described for I per cent sodium sulphide. Treat• If a Merino wool fibre 4 in. long is anchored at ment of fibres with 1 per cent sodium sulphide until each end and allowed to lie loosely in a horizontal the first coiling has been completed (6 min.), followed position in a Petri dish in water, nothing obvious by a wash in water and immersion in I per cent results. If the water is replaced with 1 per cent caustic soda, caused coiling similar to that previously caustic soda (20° C.) several phenomena may be permitted for these fibres in the I per cent sodium observed. Thus: (1) within 1 min. the original sulphide, but no subsequent straightening or further crimp disappears and the fibre appears 'lank'; (2) it coiling as would be the case were sodium sulphide goes into about three coils per inch within 3 min. ; used finally instead of 1 per cent caustic soda. Treat• (3) it goes into fine turns within 8 min.; (4) it winds ment of fibres for 6 hours with I per cent caustic up more closely, averaging 15-20 turns per inch by soda did not prevent them when afterwards immersed I5 min., after which no further action is observed; in I per cent sodium sulphide from straightening out (5) the direction of the coil reverses here and there and then coiling as described earlier. Such fibres, along the length of the fibre. however, did not disintegrate and would bear weights No similar phenomena were observed in acid of O·I-0·2 gm. without undue stretching. This is in solutions. marked contrast to the eventual gelatinous nature If, after immersion for I5 min. in I per cent sodium of wool immersed in I per cent sodium sulphide with• hydroxide, the fibre is transferred to water or acid, out previous prolonged treatment with I per cent the coils unwind ; they reappear when the fibre is caustic soda. It is evident that the prolonged action replaced in the sodium hydroxide solution. But if of the 1 per cent caustic soda makes the wool resistant the period of immersion is two hours or more, the to the disintegrating action of I per cent sodium coils do not disappear in acid or water. sulphide. Human hair, produced in a relatively straight Obviously, further fundamental chemical, physical follicle, does not coil in a solution of 1 per cent and histological studies must be completed before sodium hydroxide ; primary wool fibres, produced attempting to explain the phenomena described. in relatively spiral follicles, go into large coils ; The purpose of this note is to direct the attention of secondary wool fibres, which come from coiled other workers to these facts so that they also may follicles, go into very close coils. No closer correlation investigate what are indeed some very peculiar has yet been made on this point. Wools of characteristics of wool. breeds other than the Merino behave similarly in MARTIN R. FRENEY all these respects but are less predictable as to Australian Council for Scientific behaviour. and Industrial Research, It was found that under zero tension there was a 314 Albert Street, 2-3 per cent decrease from the original length after East Melbourne.