438 



NA TURE 



[August 31, 1905 



of albumin affords. Furthermore, before a synthesis 

 can be successfully attempted, it is necessary to know 

 whether these substances are primary or secondary pro- 

 ducts formed directly or indirectly by the action of the 

 reagent, and here again the field is still untraversed. 



Whilst great similarity exists among the constituent parts 

 of the molecule, there is a wide difference in the propor- 

 tions of each present. The protamines, which are obtained 

 from the milt (testicles) of fishes, and represent some of 

 the simplest proteids, contain a large proportion of diamino- 

 acids and a small quantity of monoamino-acids ; the 

 kindred histones, on the other hand, contain a much 

 smaller proportion of diamino-acids, but the whole group 

 of monoamino-acids. Through a series of gradations we 

 arrive finally at substances like the proteids of silk and 

 elastin, which are exceptionally rich in monoamino-acids. 



A comparison of the composition of the individual 

 albumins of food and of the living body leads to the con- 

 clusion that in digestion deep-seated changes must occur. 

 Moreover, the view is steadily growing that the albumin 

 molecule forms the basis of the two other important groups 

 of food-stuffs, fats and carbohydrates. The decomposition 

 which certain albumin fragments undergo promises to 

 throw new light on the changes which occur in the 

 organism and on the formation of pathological products. 



Granted that the whole series of albumin products 

 were known, their relative arrangement in the molecule 

 would still remain to be discovered. Attempts have been 

 made by using milder reagents to arrest the process of 

 degradation at an earlier stage, and so obtain larger mole- 

 cular fragments; but great practical difficulties attend the 

 method. Nevertheless, by the labours of Fischer and 

 Bergell a series of no less than four intermediate 

 products between silk and its lowest degradation product 

 have been isolated. First, sericoine ; secondly a sub- 

 stance containing tyrosine ; thirdly, one free from tyrosine ■ 

 and lastly, a compound which probably belongs to the 

 dipeptides mentioned below. This study of partial de- 

 gradation of the albumin molecule derives increased 

 interest from the behaviour of food albumin in the intes- 

 tine, which, as Fischer and Abderhalden have shown by 

 their experiments on dogs, probably undergo neither slight 

 nor yet complete decomposition, but partial hydrolysis 

 It will be an attractive problem to determine 'how' far 

 ood albumin may be degraded and yet afford nutriment 

 tor the organism. 



If the process of decomposition cannot furnish the 

 necessary information about the structure of the albumin 

 molecule, the reverse process of synthesis may effect the 

 desired object. E. Fischer has with wonderful experi- 

 mental ingenu^y and skill successfully followed this path 

 01 research Ihe classical memoirs on the polypeptides 

 nJl. l-^^ ''"'" "^"'''"^ '° '" 'he pages of Nature. 

 By combining two molecules of amino-acids, the dipeptides 

 glycyl-glycme, alanyl-alanine, and leucyl-Ieucine have beer! 

 «l.nl'?'„r ^^ ^%" as rni.,,ed dipeptides, e.g. glycyl-alanine, 

 aianyl-glycine, &c. By uniting three and more molecules 

 ,\u" l^"'^-P''P"des, &-C., are formed. The longest chair! 

 of this character is pentaglycine, consisting of a group of 

 hve linked glycine molecules. & H 



But,^ as we have seen, the degradation products of 

 albumin are not all monoamino-acids, but include hydroxy- 

 and diammo-compounds, and peptides of these substances 

 have also been prepared. These products show an un- 

 m.stakabe likeness to the natural peptones. They give 

 the usual reactions-the biuret reaction, precipitation by 

 phosphotungstic acid, and hydrolysis by trypsin .A 

 peculiar interest centres round the 'different behaviour of 

 the peptides towards the pancreatic ferment. Whereas 

 g ycy -Z-tyrosine and glycyl-Meucine are easily hvdrolysed' 

 glycyl-glycine and glycyl-alanine are unattacked by the 

 lerment. •' 



These experiments, as Fischer has pointed out, are not 

 only useful in indicating the physiologically important com- 

 pounds among the numerous synthetic materials obtained 

 by him but shoNV, by the experience so gained, the possi- 

 bility of discovering the different kinds of linking which 

 exist among the amino-acids of the albumin molecule 



We rnay anticipate from these investigations some know- 

 ledge of the cjiuse whereby different parts of the molecule 

 resist or retard the action of the ferment. J. B. C. 



NO. 1870, VOL. 72] 



ON THE ORIGIN OF EOLITHS.' 



pOR some time past the question of the existence of 

 man in different countries during the Tertiary period, 

 based upon flints bearing traces of intentional work, has 

 occupied the lively attention of " prehistorians " in 

 numerous parts of the globe — in France, England, 

 Germany, Russia, Egypt, India, &c. 



According to the eminent Belgian geologist, M. Rutot, 

 who has placed himself at the head of this new move- 

 ment, we must add to the PalEeolithic and Neolithic periods 

 a period more ancient still, which has received the name 

 of Eolithic. This does not comprise any type of instru- 

 ment chipped into an intentional form, but only natural 

 forms utilised at once. These primitive and rough tools 

 have received the name of eoliths. It is believed that 

 they may be recognised by the presence of secondary 

 work {retouches), that is to say, the removal of small 

 flakes in apparently a systematic manner, in accordance 

 with the needs of the case, or resulting from the wear 

 of the flint by use. 



An enormous quantity of eoliths are found in the 

 Quaternary gravels mixed with instruments of determinate 

 and classic forms. In the gravels of the north of France 

 and of Belgium, M. Rutot has described several industries 

 of this kind, the Reutelian, the Mafjiian, the Mesmnian, 

 &:c. But such objects are equally met with in beds of 

 far greater antiquity ; the chipped stones of the Oligocene 

 of Thenay, of the Miocene of Otta and Aurillac, of the 

 Pliocene of England, &c., are eoliths; and here the 

 question becomes far more grave, inasmuch as the adepts 

 in the new theories rely on these facts to admit the 

 existence of man Or his immediate precursor during the 

 Tertiary period. 



For twenty years I have not ceased to combat these 

 theories ; first, because it appeared to me to be imprudent 

 to admit the existence of Tertiary man in the absence 

 of all direct, that is to say, in the absence of osteological 

 evidence, and secondly, because I have always been con- 

 vinced that the eoliths are due to natural causes. I had, 

 indeed, had occasion to meet with them in all the ancient 

 alluvia of torrential character in which flints were present. 

 In Auvergne, and in the Velay, in the course of my explor- 

 ations in connection with the geological map, I had found 

 them at numerous points in the midst of Oligocene or 

 Miocene beds occupying thousands of square kilometres 

 in extent. I asked myself how experiments could be 

 undertaken to solve the problem of the eoliths, when M. 

 Laville, of the Ecole des Mines, brought before M. 

 Cartailhac, correspondent of the institute. Dr. Obermaier, 

 and myself some experiments carried on daily, but un- 

 intentionally, in an industrial establishment. 



There are in the Commune of Guerville, near Mantes, 

 some works in which cement is made from a mixture of 

 chalk and plastic clay. The chalk, as usual, contains 

 blocks of flint which are rejected by the diggers. Trucks 

 convey the chalk from the quarry to the neighbouring 

 works, and deliver it with a certain quantity of clay into 

 circular vats called dilayeurs. These are about 5 metres 

 in diameter and 1-40 metres in depth. The water which 

 serves them arrives by pipes, and is discharged through 

 lateral sieves, carrying with it the finest particles of the 

 mixture of chalk and clay. The water is set in motion 

 by a horizontal wheel, above the level of the water, but 

 from its spokes are suspended harrows (herses) of cast- 

 iron dipping into the water ; the speed of rotation of the 

 wheel is about 4 metres at its circumference. 



The water is thus driven into a tumultuous movement, 

 which carries away not only the particles of chalk and 

 clay, but also a certain number of flints which have 

 escaped the attention of the workmen, and have been 

 thrown into the vats together with the chalk. These 

 flints are therefore subjected to blows one against the 

 other which during a period of twenty-nine hours must be 

 e.\tremely numerous. When the machinery is stopped, the 

 flints remain at the bottom of the vat, where they are 

 covered by a coating of chalk. They are taken out of the 

 vats to be washed and placed in heaps, as they are useful 

 for making concrete. 



Now these bits of flint that while in the vats have 

 1 Translation of a paper by M. Marcellin Boule in the Comttss retd-us of 

 the Pans Academy of Sciences (June 26). 



