402 



NATURE 



[July 25, 1918 



There is one statement that we feel cannot be 

 accepted without some consideration : " If a 

 man ever scales 9 stone there must have been 

 a time at which he weighed 4\/5 stone." Is this 

 necessarily so? S. B. 



LECITHIN AND ALLIED SUBSTANCES. 



Lecithin and Allied Substances: The Lipins. By | 

 Dr. H. MacLean. (" Monographs on Bio- } 

 chemistry.") Pp. vii + 206, (London: Long- i 

 mans, Green, and Co., 1918.) Price 75. 6d. net. 



THE time had come when an account of the 

 chemistry of lecithin and allied substances 

 should be written and must be read by everyone 

 interested in bio-chemistry. Ten years ago it had 

 not. At that time the subject could only have 

 been preseoted as an unprofitable series of dis- 

 putes on insecure premises. Now there must be 

 many for whom this monograph will be a revela- 

 tion, many who, though they may have read, have 

 not collated the important contributions to the 

 elucidation of this most difficult subject that have 

 appeared in the last few years, and who, when 

 they see this done admirably, as it is done here, 

 will realise that a new epoch in the history of 

 bio-chemistry is being marked out. 



It is just ten years since Dr. MacLean published 

 the first of a series of papers in which, starting 

 from the fact that the amount of choline obtained 

 in the hydrolysis of lecithin was always less than 

 the supposed structure of this substance required, 

 he established good ground for his belief that 

 this is due to the fact that lecithin, as ordinarily 

 obtained, is mixed with kephaline, in which, as 

 we know now from the work of Parnas and his 

 associates, the basic group is aminoethanol. Dr. 

 MacLean has described a method of purifying 

 lecithin, so that it gives the theoretical yield of 

 choline, and, therefore, is free from kephaline. 

 Other impurities that are associated with lecithin 

 which he can by his method remove may, indeed,, 

 so disguise it as to make it appear as some one 

 or other of those vague phosphatides of which 

 too many have been described, and of which we 

 are told little but that they are soluble in this and 

 insoluble in that solvent, and contain nitrogen and 

 phosphorus in a certain proportion. Lecithin and 

 kephaline now mean something more than this. 



Then from the limbo of protagone there have 

 emerged sphingomyelin and the cerebrosides, with 

 their common basic component sphingosine, sub- 

 stances that forty years ago Thudicham had seen 

 before their day had come. In the last few years 

 the work of Thierfelder, of Rosenheim, of Lap- 

 worth, and, above all, of Levene, who, to the 

 advantages of a richly endowed institution, has 

 added the enthusiasm and the patience of a great 

 investigator — work that has finality — has given to 

 these somewhat ghostly shapes reality and pre- 

 cision of outline. This work on the constitution 

 of sphingosine and on the strange fatty acids of 

 sphingomyelin and the cerebrosides confers on 

 these substances a living interest, now that their 

 NO. 2543, VOL. Id] 



chemical structure is acquiring definition, as great 

 as that which has been focussed, for instance, on 

 the nucleic acids or on hsematine. In all there are 

 the same elements of novelty, mystery, and wealth 

 of biological significance. Dr. MacLean is to be 

 congratulated on his opportunity no less than on 

 the use he has made of it. 



It was no doubt unavoidable that this book, 

 coming just when it has, should still contain, in 

 addition to the chapters describing the advances 

 of recent years, whole sections devoted to the 

 unwelcome task of pronouncing judgment on so 

 many substances, named and unnamed, the dis- 

 covery of which has not been established. Dr. 

 MacLean would probably, too, have preferred not 

 to have had to commit himself in the matter of 

 nomenclature. The things that count have good 

 enough names. Lecithin, sphingosine, and 

 sphingomyelin are appropriately and successfully 

 named, though it is true as much cannot be said 

 for kephaline, phrenosine, or kerasine. Schematic 

 nomenclature matters less, and it is in this that 

 agreement has not been attained. When the 

 subject reaches the schools this will be added 

 to it. 



A FAUNISTIC SURVEY. 

 The Invertebrate Fauna of Nottinghamshire. By 

 Prof. J. W. Carr. Pp. viii + 618. (Nottingham: 

 J. and H. Bell, Ltd., 1916.) 



THE Nottingham Naturalists' Society is to be 

 congratulated on having produced a finely 

 executed survey of the invertebrate fauna of the 

 county. It is part of a surveys which was resolved 

 upon when the society completed its fiftieth year, 

 the task being placed in the competent hands of 

 Prof. J. W. Carr. He has been eflSciently helped 

 by collectors and by speciali$ts, and it is satis- 

 factory to read that "practically every species 

 recorded has been submitted to ' and named by a 

 leading authority in the group to which it be- 

 longs." The whole work shows a high standard 

 of carefulness, and it will be of great service to 

 active local naturalists, who have now an authori- 

 tative list to which they may add. That there are 

 many additions to be made is plain when we look 

 at the sparseness of the records as regards 

 Nematodes, Rotifers, Leeches, and some other 

 classes. 



Among the excellent features of this "Fauna" 

 we may mention (i) the precision which so often 

 marks the record of the particular kind of environ- 

 ment frequented by a particular species, and (2) 

 the insertion of introductory descriptions of phyla, 

 classes, orders, and sometimes even fariiilies. 

 They are tersely and clearly phrased, and greatly 

 increase the value of the lists. The consistent use 

 of different type-founts for the various grades of 

 classification from phylu'm to species is another in- 

 stance of carefulness, and the whole typography 

 is excellent. As data accumulate, the indefatigable 

 editor proposes to append supplements, and 

 already there are nearly 300 additional species of 

 Diptera waiting for admission. The Vertebrate 



