394 



NATURE 



[January 17, 19 18 



-as Ap. Belopolsky's groups have been verified and 

 added to, and the lines have been respectively identified 

 with those of europium and terbium. Many of the 

 lines not definitely recognised as being of variable 

 intensity have further been found to agree with the 

 stronger lines of yttrium, lanthanum, gadolinium, and 

 dysprosium. The peculiarities of the spectrum thus 

 appear to arise from the exceptional development of 

 lines belonging to rare earths. It may be added that 

 the presence of europium lines in this spectrum was 

 first detected by Mr. BaxandaJl, of the Solar Physics 

 Observatory, Cambridge. 



The Society for Practical Astronomy. — The 

 annual report of the president of this society for 19 16-17 

 is included in the Monthly Register, vol. ix.. No. 2 

 (1338 Madison Park, Chicago, 111.). The chief purpose 

 of the society is to promote the practical study of astro- 

 ,nomical phenomena, and to encourage co-operation 

 among its members through the various observing sec- 

 tions which have been organised. A section for the 

 teaching of astronomy, under the direction of Dr. Mary 

 E. Bird, appears to have been especially successful. 

 There is also a section for the construction of astro- 

 nomical instruments, which is directed by Prof. M. F. 

 Fullan, who is contributing a valuable series of articles 

 on .the construction of a Newtonian reflector, from the 

 grinding and figuring of the mirror to the actual 

 mounting of the telescope. 



BUTTER SUBSTITUTES. 



THE present shortage of fats, especially butter, gives 

 a particular interest to two papers published by the 

 Society of Chemical Industry. The first, printed in the 

 Journal for October 31 last, is by Dr. A. Lauder and 

 Mr. T. W. Fagan, who experimented on the utilisa- 

 tion of fatty acids for feeding purposes. The large in- 

 crease in glycerol manufacture for explosives has re- 

 sulted in the production of a quantity of fatty acids 

 much in excess of what can ordinarily be utilised. 

 According to the view now held of the digestion of fat 

 in the animal organism, there does not seem to be 

 any physiological reason why it should not assimilate 

 free fatty acids. In the authors' experiments ten 

 young pigs (about seven weeks old) were fed, the first 

 five on a mixture of maize meal and sharps, the re- 

 maining five on a smaller ration of the meal and sharps 

 mixture, together with a small quantity of the fatty 

 acids from coconut oil. About 5 oz. of the fatty 

 .acids replaced i lb. of the meals. In addition to the 

 above rations, a certain quantity of cabbage was given 

 to the pigs. The results showed that the increases in 

 the live weights of the two lots of pigs when the 

 •experiment had lasted for seven weeks were practic- 

 ally identical. The conclusion is drawn that the fatty 

 acids were assimilated, and that they replaced about 

 two and a half times their weight of carbohydrate. 



The second paper, published in the issue of Decem- 

 ber 15, by Mr. W. Clayton, deals with " Modern Mar- 

 garine Technology." The first butter substitute was 

 prepared at the time of the Franco-Prussian War by 

 Mfege-Moufies, who digested animal fat with sodium 

 carbonate solution in the presence of pepsin (from pig 

 or sheep stomach), the product being afterwards 

 churned with 10 per cent, of cow's milk and water 

 containing macerated cow's udder. In modern mar- 

 garine manufacture the fat is no longer artificially 

 digested with pepsin, whilst animal fat is more and 

 more being replaced by vegetable oils (coconut, palm- 

 kernel, cotton-seed, arachis, soja-bean, sesame, kapok, 

 maize, and wheat), and by hardened or hydrogenated 

 oil. It has been established that the very small quan- 

 tity of nickel which remains in the hydrogenated oil 



NO. 2516, VOL. 100] 



is quite harmless. In tiie preparation of margarine 

 milk is used for two primary reasons : first for flavour- 

 ing purposes, and secondly as an emulsifying agent. 

 The milk is pasteurised by heating at 82° C. for a few 

 minutes (a possible improvement would be to sterilise 

 it by means of ultra-violet light or a high-tension 

 alternating current), cooled to 10° C, and delivered 

 into souring tanks. In the latter it is inoculated with 

 lactic acid bacilli and the temperature then raised to 

 the point favourable to lactic fermentation. When 

 the fermentation has proceeded so far that the acidity 

 causes a rapid precipitation of curd the milk is again 

 cooled to a safe inhibiting temperature. The mixture 

 of vegetable and animal fats and oils is melted, 

 strained, and brought to a suitable temperature (best 

 25° C.-35° C). It is then run into a churn containing 

 the prepared milk (the milk is sometimes added to the 

 oil, but then emulsification is not so good), apd the 

 mixture emulsified by the action of revolving baffle- 

 plates. The emulsion is allowed to flow on to a 

 slanting shoot, where it meets a spray of ice-cold 

 water. This causes immediate solidification and a 

 breaking up of the mass into yellow granules. These 

 granules, after draining, are kept at a constant tem- 

 perature in a maturing room, where the bacteria intro- 

 duced by the milk can develop. Maturing takes 

 longest in the case of the best animal margarines. 

 When mature the product is kneaded to form a 

 coherent butter-like mass and to expel the excess of 

 moisture, and then passes to the blending department, 

 where it is prepared for sale. Boric acid (not exceed- 

 ing 0-5 per cent.) is generally added as a preservative. 

 Lactic fermentation imparts to the milk a pleasant acid 

 taste, but does not give it the true butter flavour. 

 Much research will be necessary before margarine can 

 be made with a ta-te like that of butter. 



E. H. 



SEA-PENS OF THE ''SIBOGA " 

 EXPEDITION.' 



"T^HE Pennatulacea of the Siboga expedition — the 

 -*■ richest collection of sea-pens made by a single 

 expedition — comprise about 550 specimens, which 

 Prof. Hickson has referred to seventeen genera and 

 forty-five species (seventeen new). Having at his dis- 

 posal this, wealth of material, and other specimens in 

 his own collection and in that of the University of 

 Manchester, Prof. Hickson has taken the opportunity 

 of making a thorough survey and revision of the 

 order. He regards the order as consisting of only a 

 few well-marked generic groups, and considers that 

 new generic names should not be introduced without 

 very strong reason. No new generic name is proposed 

 in this memoir, and several recently described genera 

 have been merged in older ones. Prof. Hickson care- 

 fully defines the descriptive terms employed in his 

 memoir in the hope that henceforward there may be 

 a greater measure of uniformity in the terminology ; 

 certainly he has set a high standard of precision in 

 the systematic descriptions. 



In the course of interesting speculations on the 

 hypothetical ancestor and the evolution of sea-pens, 

 Prof. Hickson says he is inclined to believe that 

 Cavernularia is nearer the ancestral form — which he 

 suggests was a dimorphic Alcyonacean similar in build 

 to Sarcophytum trochiforme — than Lituaria, which 

 Prof. Kiikenthal considered to be the most primitive 

 sea-pen. 



Pennatulacea were obtained by the expedition from 

 sixty-five of the 322 collecting stations, and th^ names 



1 " The Pennatulacea of th». Si/wfa Expedition, with a General Srrvev nf 

 the Order." By Prof. S. J. Hickson. Pp. x + 265+p'ates x + i chart. 

 (Leyden : E. J. Brill, 1916.) Price 13.50 franc;. 



