;22 



NATURE 



[January 5, 191 1 



calculations necessary to the revision of Le Verrier's 

 tables of Jupiter. 



2000 francs to M. Bordmann, for the completion of his 

 stellar photometer. 



2000 francs to M. Ouidor, for assistance in the publica- 

 tion of his memoir on the external morphology of the 

 parasitic copepods. 



SEX RELATIONSHIP. 



"DERHAPS one of the most subtle and interesting 

 problems of life is the numerical relationship of sex 

 and its influence on the body politic. 



It has always been something of a puzzle why the pro- 

 portion of each kind, apparently with little or no under- 

 lying reason, is produced in the right numbers. The 

 argument that if such were not the case the particular 

 species would not survive does not reveal to us the 

 methods by which this object has been achieved by nature. 

 That some mechanism must exist by means of which, 

 within certain limits, the number of males and females 

 born is regulated, is proved by the facts of history, where 

 we have numerous examples of wars and other social 

 upheavals where males have largely suffered, and yet 

 within an apparently short period of time, as measured 

 by such events, a balance has been again re-established. 

 The sex equilibrium may be compared to that of a gyro- 

 scope, where the greater the disturbance of jjosition the 

 greater is the force tending to re-establish its natural 

 stand whilst in motion. Nature in her methods never 

 does anything exactly, but approaches an object by 

 establishing lateral control, which guides her on her way, 

 should any deviation occur. Thus she does not proceed 

 along a straight line, but is continually oscillating to 

 either side. Her progress may very well be likened to 

 that of an inebriated person in search of his dwelling. 

 All that can be said is that he has a tendency home- 

 wards. 



The facts regulating sex must be something of the same 

 type, and are such that the greater the oscillation in any 

 one direction the greater must be the restraining force 

 invoked to curb or neutralise the movement. .All such 

 movements have an inertia, and consequently, like a 

 pendulum, pass the middle line and establish a negative 

 phase. The history of any race in its sex composition 

 would show us that such oscillations have occurred 

 throughout time, modified, no doubt, in their regular 

 sequence by such factors as wars and famine. These 

 oscillations of se.x balance have brought with them certain 

 changes and movements in the people themselves ; an 

 excess of males would naturally tend to produce war, 

 either civil or foreign, whilst a superfluity of females is 

 easily associated with upheavals in the domestic polity of 

 the community. There is no doubt that, could we trace 

 the history of the world, or any section of it, we should 

 see that man simply reacts to certain variations which 

 are inevitable sequences in the establishment of this 

 balance. Are there at present any indications of the 

 methods upon which, or factors by which, this state is 

 maintained? As is usually found, " truth is simple," and 

 so the workings of nature, when once discovered, are easily 

 understood. The sex constitution of our population, upon 

 which such mighty issues depend, appears to obtain its 

 regulating force from a very simple factor, and apparently 

 is correlated with age only. 



At the present time the sex balance is as follows : — 

 At birth the ratio of males to females is about 1030 to 

 1000 ; at the fifth year, owing to deaths amongst the 

 males, the balance is equal ; from the fifth to the fifteenth 

 year the mortality amongst the females is slightly higher 

 than amongst the males, but from that time onwards the 

 females relatively increase. If we take the male as a 

 few years older than the female for the purpose of mating, 

 then the balance is disturbed further still. The result of 

 this is to produce in a community a section of women who 

 cannot possibly perform that function for which they were 

 fashioned. Their energies are naturally directed into other 

 spheres, as evidence of which we see the revival of the 

 movement for political recognition. The agitation is no 

 new one, and apparently is dependent for its strength and 

 virility on the position of the sex pendulum. If the pre- 



•NTO. 2149, VOL. 85] 



sent female oscillation has not yet reached its zenith th' 

 agitation will continue ; if the reverse is happening, a- 

 there is reason to believe to be the case, then the presen 

 movement, after certain bursts of rejuvenescence, shouli' 

 slowly subside, to be again resurrected at some futui 

 epoch in the history of the world. 



The. following table gives the relationship of the agt 

 of the mother to the sex of the child : — 



(Taken jrom an Inquiry into Birth Conditions in the Town 

 of Middlesbrough.) 



All births up to 19th year 



., ,> 24th „ 



„ „ 29th ,, 



,. ,. 34th ,, 



,. » 39th „ 



All births 



England and Wales (1910) 



If taken between the stated ages 

 follows : — 



Up to 19th year 



From 20th to 24th year inclusive 



„ 25th ,, 29th „ ,, 



,, 30th „ 34th „ ,, 

 34th year and over 



It is seen that, as a matter of fact, the tendency to 

 produce females over males is present in young mothers ; 

 at more mature ages there is an excess of males. We 

 can easil}^ see how a self-regulating balance is established, 

 depending upon this fact. In a state of society in which 

 females are scarce they naturally, owing to demand, mate 

 early in life, and tend thereby to reproduce an excess of 

 their own kind (females), thus neutralising the state which 

 recently existed. On the other hand, should the males be 

 in the minority, the females will mate at more mature 

 ages, at anj' rate at ages of twenty-five and above as is 

 at present, in which circumstance an excess of males is 

 produced. We see, therefore, that the natural tendency 

 at the present time is to neutralise the female excess. We 

 may possibly look upon ourselves at the present moment 

 as being at the zenith of a female oscillation, and as time 

 progresses, helped probably by a saving of infantile life, 

 a more numerical equality of sex will be established. 



The relationship of the age of the father to the sex of 

 the child is much the same as the mother, and where 

 disparity in age occurs the influences may neutralise each 

 other, so that with a mother of about twenty years and 

 a father of about thirty years the chance of a boy or a 

 girl should be about as equal as nature can make such a 

 problem. Education is attempting to teach the inhibition 

 of self, and thus delaying the age of marriage, so that 

 the preponderance of male births should go on increasing. 

 If the present rate of progress is maintained, and allow- 

 ing for the greater mortality of the male infant over the 

 female, an average marriage rate of between twenty-seven 

 and twenty-eight years should produce a population in 

 which the males are at all periods in excess of the females. 



R. J. EWART. 



AVIATORS AND SQUALLS. 



OX looking through. the now formidable list of fatalities 

 which mark "the progress, and the dangers, of 

 aviation, the reader is often struck by the number of 

 accidents where the reason for the capsize of the machine 

 is not apparent. "Holes in the air" is the explanation 

 frequently tendered, but it seems more than probable that 

 sudden gusts, or squalls, at critical moments may be the 

 re.al factors causing the trouble. For this reason an 

 article bv M. Durand-Greville in the December (1910) 

 number of the Bulletin de la Societe astronomique de 

 France is of interest. . j. 



M. Durand-Greville proposes a system of warnings ol 



