February 6, 19 13] 



NATURE 



62- 



mankind in central Germany in post-Pleistocene 

 times; Dr. Pfeiffer's inquiry covers both periods. 



The tumulus explored by Dr. Moller (he had 

 great difficulty in obtaining permission to under- 

 take the work) lies about twenty miles north of 

 Weimar, on a slight elevation among the fiat fields 

 which border the Unstrut — a tributary of the 

 Saale. Interments were discovered which date 

 from the early part of the Neolithic period down 

 to mediaeval times — roughly speaking, from 

 3-4000 B.C. to 1000 A.D. A section of the tumulus 

 — oval in shape and measuring 30 metres in its 

 longest diameter — revealed within it a small 

 tumulus, covering a single interment, of the early 

 Neolithic period. On the southern margin of the 

 smaller and older tumulus were three intrusive 

 burials — in the contracted posture — also Neolithic 

 in date. At the southern base of the tumulus, at a 

 still later Neolithic date, there had been placed a 

 cyst, or slab tomb, flanked with altar floors. The 

 larger tumulus, which covers the older and smaller 

 one, had been thrown up over a fourth interment, 

 a cyst burial, covered with a cairn of stones, which 

 is ascribed to the close of the Neolithic period. 



These four burials of the Neolithic period were 

 accompanied by such evidence that their sequence 

 and date could be determined with a fair degree of 

 accuracy. The Bronze period is represented by 

 only one interment, the body having been entombed 

 within a dug-out canoe. The pre-Christian period 

 was represented by three urn-burials ; the tomb 

 of a warrior of the fifth or sixth century marked 

 the Merovingian age ; lastly, numerous graves of 

 people buried in early Christian times (ninth and 

 tenth centuries) occurred all over the large 

 tumulus. Dr. MoUer's attention was more parti- 

 cularly directed to the pottery and other accom- 

 panying evidences of civilisation, which gave him 

 a clue to the dates of the various interments. 

 The skeletal remains of the men, women, and 

 children buried in the tumulus, often reduced to 

 little more than dust, are only incidentally touched 

 upon. It will be thus seen that, in expert hands, 

 tumuli become the most valuable of prehistoric 

 ■documents 



In Dr. Soergel's memoir a most useful contribu- 

 tion is made to the systematisation of our know- 

 ledge of the larger mammals which became extinct 

 towards the end of the Pleistocene period. Every 

 palaeontologist has observed that the extinction of 

 these great animals is coincident with the progress 

 and distribution of human races in the Pleistocene 

 period. Indeed, Dr. Steinmann [Die geologischen 

 Grundlagen der Abstammungslehre, igo8) came 

 to the conclusion that their extinction took place 

 at the hands of man. Dr. Soergel does not agree 

 with that view ; he holds that the frequent changes 

 of climate in the Pleistocene epoch led to a mani- 

 festation of a high degree of variability amongst 

 certain of the mammalian genera, and that the 

 forms which became most highly specialised- — ■ 

 such as the Irish elk — in contradistinction to the 

 less specialised form — Ccrvus dama — became ex- 

 tinct because of their highly specialised characters. 

 An unprejudiced survey of the evidence inclines 

 NO. 2258, VOL. 90] 



the reviewer to regard Dr. Steinmann's conclusion 

 as the nearer approximation to the truth. 



Dr. Pfeiffer's memoir — by far the more important 

 of the three — is an honest attempt to lay archaeo- 

 logy, so far as it is concerned in investigating the 

 evolution and history of human handicraft, on a 

 firm foundation. His work is beautifully illus- 

 trated, and he has spared no pains to obtain 

 evidence by experiment and by direct observation. 

 The scope of his memoir will be best indicated by 

 giving the titles of its seven chapters: i., the 

 technique employed in fashioning stone imple- 

 ments during the periods of stone; ii., the physical 

 conditions determining the various forms of tech- 

 nique employed; iii., various forms of fashioned 

 stones; iv., the bone implements of the Stone 

 periods; v., wood implements of the Stone periods : 

 vi., the utilisation of the products of the chase; 

 vii., the extinction of the industries of the Stone 

 periods. Dr. Pfeiffer does not touch on the evid- 

 ence of a high surgical technique amongst the 

 people of the Neolithic period. The ancient skulls 

 with clear signs on them of extensive operations 

 and limb-bones with well-healed fractures show 

 that there were daring and successful surgeons 

 amongst the Europeans of the Neolithic period. 



THE PASTEURISATION OF MILK. 



IN a former article on " Tuberculosis and the 

 Milk Supply " (N.\ture, November 7, 1912, 

 p. 281), reference was made to pasteurisation as 

 one of the means suggested for the provision of 

 a pure milk supply. 



Pasteurisation, as applied to milk, is a process 

 of somewhat indeterminate nature. It denotes 

 the heating of milk to a temperature which may 

 range between 140° F. and 165° F. in "bulk" 

 pasteurisers, in which the milk remains, and is 

 maintained at the temperature employed during 

 the whole period of treatment — some 20-30 

 minutes — or up to i8o° F. in "flash" pasteurisers, 

 in which the milk flows continuously through the 

 apparatus and the period of heating is a brief one. 

 In both cases the milk is immediately nm on to 

 coolers. Either method fulfils more or less com- 

 pletely the objects for which pasteurisation is 

 carried out, which are (i) to destroy pathogenic 

 micro-organisms, such as tubercle, typhoid, and 

 diphtheria, that may have gained access to the 

 milk ; (2) to reduce the bacterial content of the 

 milk, and, as a consequence, (3) to enhance the 

 keeping qualities of the milk, and to allow its 

 distribution in a merchantable condition. The 

 treatment undoubtedly effects these objects more 

 or less efficiently, but it remains to consider in 

 what manner the after-condition of the milk may 

 be influenced thereby. 



By heating milk above a temperature of 165° F. 

 a more or less rapid destruction of the lactic-acid- 

 producing organisms occurs, while the more re- 

 sistant putrefactive forms largely survive the 

 treatment, and it is owing to this change in the 

 bacterial flora that danger arises should the milk 

 subsequently be kept at temperatures favourable 



