SOME PHYSIOLOGICAL RESULTS OF TEMPERATURE VARIATIONS. Ze 
Having shown that the conception variations are produced chiefly by changes 
in temperature, it is necessary to determine more definitely the influence, and 
to find out the percentage increase which would follow an elevation of 1° (Fahr.) 
or unit of temperature, | 
By calculating from the original numbers in the register books, or still better, 
perhaps, by comparing the altitudes in Fourier’s curves, it will be seen that 
an elevation of 1° (Fahr.) causes an increase of about ‘5 per cent. 
This can readily be done from the Fourier curves. The altitude of the 
primary temperature curve is 10 units above the mean, while the altitude of 
the corresponding conception curve is 162 units. Therefore 1 unit is the cause 
(or corresponds to) 16:2 of conception. 
To arrive at the percentage, find out the average mean number of monthly 
conceptions, which is 3127, Therefore 1° or unit causes an increase of 16:2 
conceptions over the mean of 3127, or ‘51 per cent. This may be taken roughly 
at ‘5 per cent., it being absurd to state such a law very exactly where so many 
slight fallacies exist, from false registration and otherwise. 
The influence of temperature on conceptions may be stated as a physiological 
law as follows :— 
“Temperature is the main factor regulating the variations in the number of 
conceptions (and consequently of births) which occur during the year, It 
increases their number with its elevation, and this on an average of ‘5 per cent. 
for an elevation of 1° Fahr. (in Scotland).” | 
It would be interesting to know what produces the secondary and other 
waves of temperature given by Fourier’s analysis. 
May it not be, that the one with a maximum in spring and autumn (the 
secondary curve) is caused by the local winds which then occur, and which no 
doubt greatly influence local temperature, being probably the great cause of its 
local variation (these themselves, of course, being primarily due to temperature) ? 
Marriage Factor. 
By examining Chart II. or the following figures, it will be seen that in January 
the number of marriages contracted is very high. The numbers fall through 
February to March, rising in April only to fall again in May. From May, the 
month in which fewest marriages occur, the numbers suddenly rise to their 
highest maximum in June ; falling through July, August, September to October, 
rising again in November, and falling slightly in December. 
Average Marriage Curve of Years (1866-1875) inclusive. 
January, = 1245 
February, 611 
VOL. XXIX, PART I. 21 
II 
