Hilda Margaret Bruce (5 April 1903 – 2 November 1974) was a British

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

, best known for her discovery of the

Bruce effect The Bruce effect, or pregnancy block, is the tendency for female rodents to terminate their pregnancies following exposure to the scent of an unfamiliar male. The effect was first noted in 1959 by Hilda M. Bruce, and has primarily been studied in ...

, a pheromonal behaviour observed in many

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

species. Her work on the control of fertility earned her the Oliver Bird Medal.

Biography

Hilda Bruce was born on 5 April 1903. She was educated at

St Leonards School St Leonards School is an independent boarding and day school for pupils aged 4–19 in St Andrews, Fife, Scotland. Founded in 1877 as St Andrews School for Girls Company, it adopted the St Leonards name upon moving to its current premises, the s ...

. In 1923, she began her tertiary studies at King's College for Women, where she received a BSc in Household and Social Science, and another in

Physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...

. In 1928, Bruce joined the

National Institute for Medical Research The National Institute for Medical Research (commonly abbreviated to NIMR), was a medical research institute based in Mill Hill, on the outskirts of north London, England. It was funded by the Medical Research Council (MRC); In 2016, the NIMR b ...

(NIMR) at Mount Vernon, Hampstead. Her early research was dedicated towards the understanding of

Vitamin D Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...

; she also jointly published the first article describing the breeding characteristics of the

golden hamster The golden hamster or Syrian hamster (''Mesocricetus auratus'') is a rodent belonging to the hamster subfamily, Cricetinae. Their natural geographical range is in an arid region of northern Syria and southern Turkey. Their numbers have been d ...

. In 1933, Bruce was employed by the Pharmaceutical Society, where she continued her research on Vitamin D. In 1941, she was appointed to set up the Cod Liver Oil (Poultry) Standardisation Laboratory. In 1944, she returned to the NIMR, where she formulated specialised diets for

laboratory animal Animal testing, also known as animal experimentation, animal research, and ''in vivo'' testing, is the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study. This ...

s. From the early 1950s, Bruce turned her attentions towards

sexual behaviour Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., masturbation) ...

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...

, particularly the

Whitten effect The Whitten effect is stimulation, by male pheromones, of synchronous estrus in a female population. Social signals, or social stimuli, have an effect on reproduction in all mammals. For certain female mice, the pheromones contained in the urine ...

. In 1959, she published her discovery of what is now called the

, the

termination of pregnancy Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of pregnan ...

following exposure to the scent of an unfamiliar male. Bruce retired from the NIMR in 1963, but continued

part-time Part-time can refer to: * Part-time job, a job that has fewer hours a week than a full-time job * Part-time student, a student, usually in higher education, who takes fewer course credits than a full-time student * Part Time Part Time (styliz ...

research, variously on

nutrients A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped *Photographi ...

and

pheromones A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

, at the Department of Investigative Medicine in

Cambridge Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge bec ...

. She continued work at the Department until 1973. In her later years, Bruce largely used a wheelchair, having been afflicted with worsening

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...

since 1942.

Bruce effect

Throughout the 1950s, Bruce studied

in laboratory mice, with a particular interest in oestrus synchronisation. In one experiment, she housed newly mated pregnant females with male mice that were not the father of the carried embryo. As a result, the rate of

miscarriage Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical lo ...

s increased, these females subsequently returning to

oestrus The estrous cycle (, originally ) is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous ...

and mating with the new male. No increased rate of miscarriages occurred when pregnant mice were paired with juvenile or

castrated Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharmaceut ...

mice. Her colleague Alan Parkes, who had recruited her to the NIMR in 1944, helped her to pursue the initial findings that eventually lead to this discovery.

The National Institute for Medical Research

Following the isolation of pure vitamin D in 1931, Bruce worked in collaboration with Askew, Philpot and Webster in the Department of Biological Standards, determining the stability of the pure substance. At this time, Bruce was also working with Dr Callow in the Department of Physiology, Pharmacology and Biochemistry, determining the healing effect of vitamin D in rats with rickets.

Publications

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References

{{DEFAULTSORT:Bruce, Hilda British mammalogists English zoologists 1903 births 1974 deaths Women mammalogists Women zoologists National Institute for Medical Research faculty Alumni of King's College London People educated at St Leonards School 20th-century Argentine people 20th-century British zoologists 20th-century British women scientists