May 24, 1906] 



NA TURE 



81 



of the summer half of the Celtic year, marking the 

 victorious close of the sun's contest with the powers of 

 darkness . . . when the crops were fast coming to 

 niaUirity," and he suggests that the great festival held on 

 I he first of August " at Lyons (ancient Lugdiina) super- 

 seded an older feast held on that day in honour of Lug, 

 and was the Gallo-Roman continuation of the Celtic custom 

 of old days." Gwyl Avvst (the Yule of August) is the name 

 l)v which this same August festival was known in ancient 

 \Vaks. 



lie remarks that " the Lugnassad was, so to speak, the 

 Suinmer Solstice of the Celts, whereas the longest day was 

 ihrn of no special account " (Rhys, Hibbert lectures). 



\'cry interesting accounts of an .'\ugust festival are given 

 by Mr. Frazer (" Golden Hough ") as celebrated by the 

 Creek Indians and also by the Natchez tribe on the Lower 

 Mississippi, when fires were lighted to destroy what was 

 old before the ceremonial renewal of new fire took place 

 In' the priests by the friction of two pieces of wood, on 

 the appearance of the first ray of the rising sun. 



.Among the special marks distinguishing the primitive 

 ritual of heathendom from later customs, Mr. Frazer 

 remarks that there were no temples, but that the celebra- 

 tions took place by brooks, in woods, barns, harvest- 

 fiekls, &c. 



This interesting fair is clearly a survival from pre-Celtic 

 days, but the interest in the place has unfortunately been 

 much obscured by the alteration of the old name Tan to 

 St. .Anne's Hill on all modern maps. 



It was a very common and well-known custom of the 

 Church in late times to alter the name of a place to that 

 of a saint, where, finding large gatherings assembled for 

 religious ceremonies, their object was to substitute 

 Christian for heathen ideas. Cacr Anna in Brittany be- 

 caine St. Anne d'Auray, and Tan Hill became St. .Anne's 

 Hill. St. .Anne's Day was not fixed for the whole Latin 

 Church until 1584, when Gregory XIII. appointed the feast 

 to be held on July 26 (.August 6) ; the name of St. .Anne 

 loes not occur in the older church calendars, and her cult 

 is a very late one. 



ThEREZ.A STORV-MASKI-r.VNE. 



Carbon Dioxide in the Breath. 



The presence of 006 per cent, of carbon dioxide in tlv 

 atmosphere is held, I believe, to render the air unfit for 

 breathing purposes, whereas 003 per cent, may be taken 

 as normal. A consideration of the quantity of this gas 

 which must be continually present in the lungs makes such 

 sensitiveness on their part to appear rather extraordinary. 



Taking an average expiration as 300 c.c. and the reseive 

 " air " in the lungs as 2000 c.c, and assuming that the 

 atmosphere contains 003 per cent, of carbon dioxide and 

 expired air 4 per cent, of carbon dioxide, we have the 

 following figures (a homogeneous mixture in the lungs i^ 

 imagined for simplicity) : — 



Just after 

 inspiration 



221991 ... C.c. air 

 S009 ... ,, CO., 



Just before 

 expiration 

 2208 

 92 



Ju.t afie 



2300 



,, in lungs. 



Hence before the next expiration iigi c.c. of carbon 

 dioxide must accumulate to make up the original 92 c.c, 

 the corresponding oxygen being absorbed. 



Now if conditions remain the same, excepting that the 

 atmospheric carbon dioxide reaches 0-06 per cent., we have 



2300 



in lungs. 



Before the next expiration 11-82 c.c. of carbon dioxide 

 are required to make up the original 92 c.c. 



Comparing these numbers, ii-qi and 11S2, we find that 

 in the case of a person breathing at the rate of sixteen 

 times a minute, only one more respiration would be re- 



quired every seven minutes to get rid of the extra carbon 

 dioxide due to an increase of 03 per cent, in the atmo- 

 sphere. 



One is tempted to wonder, therefore, whether carbon 

 dioxide per se in these small quantities can have any 

 appreciable effect. Or, on the other hand, is it possible 

 that this gas in the lungs is in some manner "vitalised," 

 as questioned by Prof. Meldola some time ago (see Nature, 

 1902, vol. Ixvi., p. 492), and that on reaching the outer 

 world it is in a short tiine changed into the ordinary and 

 more poisonous form? F. Southerden. 



Royal Albert Memorial College, Exeter, April 25. 



AMERICAN PALMOBOTANY.' 



THE.SE two volumes form the second instalment, 

 under the editorship and to some e.xtent the 

 authorship of Mr. Lester Ward, of a detailed report 

 on the Mesozoic floras of the L'nited States, the first 

 part of which ap[)eared in the twentieth annual report 



-Jurassic Ginkgo leaves from Oregon. (From "Status of the 

 ■ : Fleras of the United States.") 



NO. 1908, VOL. 74] 



of the U.S. Geological Survey published in 1900. 

 The second paper deals with Triassic, Jurassic, and 

 Lower Cretaceous floras, and includes observations on 

 the stratigraphical relations of the plant-bearing 

 strata. 



The excellent quality of the plates, many of which 

 consist of photographic reproductions of specimens, 

 is in welcome contrast to the unsatisfactory figures 



1 " Status of the Mesozoic Floras of the United Slates," Second Paper. 

 By Lester F. Ward, with the collaboration of William M. Fontaine, .\rthur 

 Bibbins, and G. R. Wieland. Pan i., Text. Pan ii,. Plates. Pp. 616; 

 Plates ,i-cxix. Monographs of the U.S. Geologicil Survey, vol. xlviii. 

 (Washington, 1905 ) 



