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IV.—On some Physiological Results of Temperature Variations. By JoHn 
Berry Haycrart, M.B., C.M., B.Sc., Assistant to the Professor of 
Physiology (Edin. Univ.). Communicated by Professor TuRNER, 
one of the Secretaries to the Society. (Plate I.) 
(Read 17th February 1879.) 
While trying to verify by actual statistics some of the ‘‘ Laws of Population” 
first enunciated by MALruHus, a curious fact was observed, viz., that some seasons 
of the year are more prolific in the number of births than others. 
This led to the further investigation of the subject, the results of which are 
before the Society. 
In pursuing this inquiry, data were drawn from the monthly returns of births, 
deaths, and marriages (Scotland). I may here express my hearty thanks to 
| Dr Witi1Am Rosertson, for much kindness shown in furnishing the necessary 
reports. 
| Two courses were open: to take the births of the whole of Scotland, where 
| the illegitimate are mixed together with the legitimate, therefore vitiating the 
results when compared with the marriages ; or to take only data from the legi- 
_ timate births of ‘The Eight Large Towns of Scotland,” where seasonal varia- 
‘tions in the number of inhabitants are continually taking place, there being 
/always more in winter than in summer “in town.” 
It was deemed advisable to avoid both fallacies by working with both sets 
| of data, the one correcting the other. 
The data quoted in this paper are those, however, of the eight large towns 
alone, those of Scotland generally not being given for sake of brevity. They 
will be, notwithstanding, quoted once or twice to correct the other. 
In all cases large numbers were used, and these numbers taken never from 
the single year’s returns alone, but always from an average of at least ten. 
On studying the monthly returns of “births,” it is seen that there are some 
| months in the year in which more births occur than others. 
Thus in April of every year there are more than in November. 
Averaged Monthly Returns of Births of Years (1866-1875) inclusive, 
Corrected to equal Months of 30:42 Days. 
January, = 3154 births (legitimate). 
February, = 3057 . 2 
March, = SPAT rs 5 
April, = 3387 7 3 
VOL, XXIX, PART I. PAae | 
