[3] In October 1892 Macmillan was among the first female students to enrol at the university, she was however not the first to graduate as others were either more advanced in their studies or taking higher degrees.

Macmillan studied science subjects including Honours Mathematics with George Chrystal, Astronomy with Ralph Copeland, and Natural Philosophy with Peter Guthrie Tait and Cargill Gilston Knott.

[4] In the summer of 1896 she went to Berlin for further university study, then returned to Edinburgh and passed an examination in Greek language to enter the Faculty of Arts in October 1896.

During this time she was a member of the Edinburgh Ladies' Debating Society, a forum which helped her gain confidence arguing in the face of opposition.

In Scotland, Glasgow's The Herald reported that she began nervously but warmed to her subject and "argued law in an admirable speaking voice".

[4] Two days later she continued to plead her case, this time in "complete self-possession", wearing a dark red outfit and hat trimmed with ermine furs.

"[10] No matter her exact words, her time at the House of Lords attracted worldwide publicity which proved valuable to the women's cause.

Macmillan was responsible for writing about the UK, the US, New Zealand, Australia, India, China, South Africa and five smaller countries.

She wrote from both personal experience and outside observation of women's activists: "as soon as they become alive to this fact, they have tested the legality of their exclusion in the law courts.

[15] The pacifist women of Germany were forced by war to withdraw their invitation to host the annual IWSA congress which was to have been held nine months later in Berlin.

[17] Taking these messages as her inspiration, Catt proposed that, rather than holding a woman suffrage convention in Berlin, an international peace congress of women should meet in The Hague for four days beginning 28 April 1915.

[16] When this announcement reached the UK, the NUWSS was divided on the one hand by patriots such as Millicent Fawcett who were devoted to war work and on the other by the signers of the Christmas letter who wished to send peace delegates.

[14] They rejected a resolution favored by internationalists Helen Bright Clark and Margaret Bondfield[18] which would have supported a delegation of women at The Hague.

At The Hague 28 April to 1 May 1915, a large congress of 1,150 women from North America and Europe gathered to discuss peace proposals.

The Wisconsin Plan was unanimously adopted as the optimum method for returning peace to the world,[17] and Macmillan, Schwimmer and the committee travelled to the neutral US to present President Woodrow Wilson with it.

The Congress strongly condemned the harsh surrender terms that were being planned for Germany in the Treaty of Versailles to be signed the next month.

Following the passing of the Sex Disqualification (Removal) Act 1919, which enabled women to become members of the legal profession, Macmillan applied to Middle Temple as a pupil barrister.

[citation needed] As she was studying for the bar, she co-founded the Open Door Council for the repeal of legal restraints on women.

[8] NUWSS was re-organised in 1918 as the National Union of Societies for Equal Citizenship, but Macmillan disagreed with the group's stance on protective legislation for women workers.

[8] Feminist writer Cicely Hamilton wrote of Macmillan that "she was the right kind of lawyer, one who held that Law should be synonymous with Justice ...

Women who were married to foreigners were, upon declaration of war, faced suddenly with status as enemy nationals within the land of their birth.

To that end, she wrote a piece entitled "The Nationality of Married Women" that was published twice in Jus Suffragii, once in July 1917 and again with updated statistics in June 1918.

Intense lobbying by women, and a massive parade demonstration, failed to influence the conferees, and the international law continued to hold that a woman's nationality followed her husband's.

In her will, she specified bequests to the Open Door International for the Economic Emancipation of the Woman Worker, and to the Association for Moral and Social Hygiene.

[27] The prize was founded as an annual grant to benefit female law students scoring the highest in the bar's final examination, and to support societies with which Macmillan was associated.

The plaque notes that she was a "suffragist, founder of Women's International League for Peace and Freedom", as well as the being the "first woman science graduate of the University" in acknowledgment of her achievement in 1896.

[25] Her name and picture (and those of 58 other women's suffrage supporters) are on the plinth of the statue of Millicent Fawcett in Parliament Square, London, unveiled in 2018.