An historical look at embryo transfer.

Abstract

If this, the International Embryo Transfer Society, were to take a 'patron saint', he would have to be Walter Heape (Plate 1), not just because he performed the first embryo transfers at the end of the last century but because of his immense influence on sciences that are fundamental to the work that we do. Although his transfer work in rabbits (1891, 1897b) was aimed at answering the 'pure' scientific question of whether the uterine environment influences an embryo's phenotype, and at defining the mechanisms of the supposed phenomenon of telegony, Heape's contribution to 'applied' science included the rekindling of interest in artificial insemination (1897a, 1898) and the laying of a scientific foundation to the animal breeding industry with emphasis on its economic importance (1899, 1906). Heape's scientific heirs in reproductive physiology at Cambridge, F.H.A. Marshall and Sir John Hammond, judged (1946) his most important work to be his memoir on The Sexual Season of Mammals (1900), in which he brought together all that was then known about breeding seasons and oestrous cycles and introduced the very terms we use today in describing the phases of the cycle. Marshall (1930) also indicated Walter Heape's versatility in an obituary describing a career that included business endeavours, elephant hunting and the invention of a high-speed camera, the "Heape and Gryalls Rapid Cinema Machine", in addition to his wide-ranging biological pursuits. Marshall's own book on reproductive physiology (1910) was the first on the subject and is dedicated to Walter Heape who would have played a considerable part in forming the ideas behind Marshall's introductory statement (page 1) that "... generative physiology forms the basis of gynaecological science, and must ever bear a close relation to the study of animal breeding." The same book draws heavily on Heape's writings, including (p. 334) his 1905 postulation that oestrus depended on an interaction between a "generative ferment" and "gonadin", secreted by the generative glands. This was at a time when the first inklings of an endocrine function for the ovary had only just been gained by the gynaecologists Knauer and Halban in Vienna (see Corner, 1961), so such a prescient hypothesis, 18 years before the demonstration of ovarian oestrogen (Allen & Doisy, 1923), would seem to deny the later assertion (Parkes, 1949) that Walter Heape regarded the ovary "merely as a producer of eggs". But it is eggs that concern us now, so let us go back to 27 April 1890 and examine what knowledge would have been at Heape's disposal when he did that first transfer. The environment of the time can be considered in relation to other major events in biology and with special regard to the history of techniques essential to embryo transfer.