A biometric analysis of some insemination-labour and menstrual-labour curves in certain mammalia / by D. Berry Hart.

  • Hart, D. Berry (David Berry), 1851-1920.
Date:
[1913?]
Catalogue details

Licence: In copyright

Credit: A biometric analysis of some insemination-labour and menstrual-labour curves in certain mammalia / by D. Berry Hart. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    menstrual-labour durations in women, a frequency polygon could in each case be constructed. In Tessier’s ewes the curve from 912 labours was a lofty symmetrical one, slightly skew on the right side. The dates were given in 24-hour intervals, and were continuous over 11 days. In the others (Spencer’s, von Winclvel’s, and Keid’s) the curve was interrupted by peaks when grouped in 24 - hour intervals, but was still of a frequency nature. When Spencer’s were taken in 48-hour groupings, the curve smoothed out (Fig. 1). In von Winckel’s and Eeid’s a 96-hour grouping gave the same result, i.c., a fairly smooth and symmetrical frequency curve was obtained (Fig. 3 gives Eeid’s). The irregularities in the Spencer, von Winckel, and Eeid statistics seemed to me to be due to the close 24-hour grouping and to the consequent separation of births happening near mid- night from those quite close to them shortly after midnight. By grouping them in 48- or 96-hour periods this mal-allotment may have been avoided to a great extent. The question still arose, however, as to the propriety of smoothing out these curves by a means of which the method was not quite clear, and therefore one had to face this point— Given 24-hour groupings with the peaked irregularities, what could be made of them by biometric treatment—would Gauss’s method of least squares be of use ? I therefore consulted my friends Mr. J. D. Hamilton Dickson, Fellow and Tutor of Peterhouse, Cambridge, and Dr. A. Daniell, wliose Text-Booh of Physics is well known, as to this, and was fortunate enough to enlist their sympathy and active help in the question. Mr. Dickson worked out Spencer’s and Eeid’s data, and Dr. Daniell treated the question from the curve point of view, so that from their most valuable help I am now enabled to bring the matter up again with benefit to the elucidation of the practical obstetrical questions—what is the significance and accuracy of a labour date calculated from a single insemination in cows or from the last day of the last menstrual period in the human female ? What is the most probable insemination-labour duration in cattle and the most probable menstrual-labour duration in the human female ? These data may be regarded as the varying measurements between insemination and labour or between the last menstruation and labour, and can therefore be treated by Gauss’s method of least squares, a form of mathematical inquiry used in astronomical observation data, and, in general, by statistical observers, to settle, in any series of observations of the same or similar objects, the