April 22, 1922] 



NATURE 



529 



Research Items. 



The Ice Age and Man. — In the January and 

 April issues of Man, Messrs. H. J. E. Peake and 

 J. Reid Moir have pubhshed schemes correlating 

 the palaeolithic types of culture with the geological 

 strata. The conclusions proposed by both writers 

 agree fairly, except that in Mr. Reid Moir's scheme 

 the position of the Alpine glaciations has been 

 moved up one stage. On this Mr. Peake remarks : 

 " According to Mr. Reid Moir the Mousterian stradaies 

 the Riss, while Obermaier has argued with much 

 force that it straddles the Wiirm, and the Mag- 

 dalenian immediately precedes the Wiirm, while 

 Penek and Schmidt have shown that this phase 

 extended into the Biihl. This divergence seems to 

 require some explanation." 



Rush and Straw Crosses. — Rude bundles of 

 straw or rushes, in the form of crosses, are often found 

 hung over the doors in many parts of Ireland on 

 St. Brigid's Day, the February festival marking the 

 end of winter and the beginning of spring. Miss 

 E. Andrews, who discusses the question in the April 

 issue of Man, with a good illustration, suggests their 

 connection in form with the Swastika, and infers 

 that we have in them a very ancient symbol used in 

 pagan times to represent the sun emerging from the 

 darkness of winter. This ingenious explanation is 

 supported by a certain amount of evidence, and it 

 deserves consideration. 



Animals on the Roof. — In the March number 

 of Folk-lore, Prof. H. J. Rose of University College, 

 Aberystwyth, attempts to explain a passage in 

 Petronius where Trimalchio speaks of Asinus in 

 Tegulis — the portent of an ass appearing on the tiles. 

 He brings together a number of examples showing 

 that in the lower culture the appearance of an animal 

 or a bird on the roof is regarded as portentous. 

 This leads to the consideration of the roof in connec- 

 tion with beliefs regarding the house. He suggests 

 that in the case of Trimalchio's ass the animal may 

 have been conceived as an evil spirit or a new and 

 particularly disagreeable form of ghost. The uncanny 

 effect of fire-light on the rude thatching and the 

 smoke-wreaths, the strange scratchings and patter- 

 ings of small nocturnal animals running over the 

 top of the hut, nightmares in which the roof threatens 

 to fall and crush the sleeper, real injuries from the 

 collapse of the flimsy structure, the intrusion of 

 beasts of prey, bats, moths, and small birds fluttering 

 about inside — all these and many other factors may 

 well have united to make up the sum of this curious 

 chapter of folk-belief. 



Cytoplasmic Inclusions of the Germ-cells. — 

 The discovery of the chromosomes and their behaviour 

 both in ordinary cell-division and in the maturation 

 of the germ-cells opened up a new era in the study 

 of the mechanism of heredity, and it is now widely 

 believed that the chromosomes are the bearers of 

 " factors " or " genes " that are responsible for the 

 transmission of heritable peculiarities. In recent 

 years, however, a good deal of attention has been 

 paid 10 certain structures, the " mitochondria " and 

 " Golgi apparatus," that occur in the cytoplasm, 

 outside the nucleus, and it has been suggested that 

 the mitochondria, at any rate, may constitute the 

 protoplasmic basis of heredity. In the current 

 number of the Quarterly Journal of Microscopical 

 Science (vol. 66, part i) Prof. J. Bronte Gatenby 

 concludes his notable series of memoirs on " The 

 Cytoplasmic Inclusions of the Germ-cells," and ex- 

 presses the opinion that " As direct bearers of any 

 important or precise factors of heredity, the Golgi 



NO. 2 73 8, VOL. 109] 



body and mitochondria appear to be ruled out by 

 their inexact and variable behaviour in the germ-ceu 

 cycle. The chromosomes, and the chromosomes 

 alone, fulfil the necessary conditions." 



Enteronephric Excretory Organs in Earth- 

 worms. — A few years ago a remarkable " enteronephric" 

 system of excretory organs in Pheretima was described 

 by Dr. K. N. Bahl, consisting of modified nephridia 

 which open by a system of ducts into the ali- 

 mentary canal, instead of opening on the surface 

 of the body as in the usual (integumentary) type. 

 The system consists of septal and pharyngeal 

 nephridia. It was a matter of considerable interest 

 to determine whether these modified nephridia are 

 formed from the epiblast of the embryo, like ordinary 

 nephridia, or whether they develop in some other 

 way. Dr. Bahl has now investigated this problem 

 and gives in the Quarterly Journal of Microscopical 

 ■Science, vol. 66, Part i, a detailed embryological 

 account of the organs in question, as well as of the 

 integumentary nephridia of the same worm. He 

 finds that all three types can be traced back to the 

 original epiblastic row of nephridial cells. The 

 connection of the enteronephric system with the 

 alimentary canal is evidently a secondary feature 

 that has arisen comparatively late in phylogeny. 



The Effect of Temperature on the Absorption 

 Spectra of Glasses. — The observations of Houstoun 

 on the absorption spectra of eight or nine kinds of 

 coloured glass showed in 1906 that, while in most 

 cases an increase of temperature from 15° C. to about 

 330° C. produced in the visible spectrum an increase 

 in the absorption on the longer and a decrease on the 

 shorter wave length side of an absorption band, this 

 was not invariably the case. Nor was the absorption 

 in all cases decreased by increase of temperature. 

 Gibson in 1916 investigated five glasses at -180° C. 

 and 430° C. in the visible part of the spectrum, and 

 found in some cases, as for instance that of a red 

 glass, that the absorption for a particular wave length 

 increased at the higher temperature to fifty times its 

 value at the lower. In a Ph.D. thesis of the Univer- 

 sity of Pennsylvania recently issued, Mr. G. Rosen- 

 garten describes his measurements of the absorption 

 of a number of coloured glasses in the infra-red 

 between wave lengths i and 5 x lo^* cm. His source 

 was a tungsten lamp, his spectrometer prism of rock 

 salt, and the issuing radiation was measured by a 

 thermo-pile. Up to 500° C. he finds the changes in 

 absorption seldom exceed the instrumental error of 

 8 per cent. 



Colour Sensitive Photographic Plates. — We 

 have received from the Bureau of Standards, Wash- 

 ington, a copy of a communication entitled " Studies 

 in Colour Sensitive Photographic Plates and Methods 

 of Sensitising by Bathing," by Francis M. Walters, 

 Jr., and Rayrriond Davis. The authors describe 

 their methods of investigation, and deal with pina- 

 cyanol in considerable detail. They have also in- 

 vestigated the use of dicyanin, erythrosin, pinaverdol, 

 pinachrome, orthochrome T, and homocol, as well 

 as the hypersensitising of commercial panchromatic 

 plates. They find that the various dyes require 

 different methods for their most successful applica- 

 tion. The previous washing of the plate to be treated 

 is sometimes of great importance, and the effects of 

 alcohol and of ammonia need, perhaps, more attention 

 than they have hitherto received. The paper is well 

 illustrated. It is ready for distribution and any one 

 interested may obtain a copy from the Bureau until 

 the free stock is exhausted. 



