Page 58. " Immediately a babel broke out "

"Babel" means a chaos of simultaneous voices. The term comes from the Biblical account of the Tower of Babel, referenced in Genesis 10:10 and 11:1-9:

And the whole earth was of one language, and of one speech. And it came to pass, as they journeyed from the east, that they found a plain in the land of Shinar; and they dwelt there. And they said one to another, Go to, let us make brick, and burn them throughly. And they had brick for stone, and slime had they for morter. And they said, Go to, let us build us a city and a tower, whose top may reach unto heaven; and let us make us a name, lest we be scattered abroad upon the face of the whole earth. And the LORD came down to see the city and the tower, which the children of men builded. And the LORD said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do. Go to, let us go down, and there confound their language, that they may not understand one another's speech. So the LORD scattered them abroad from thence upon the face of all the earth: and they left off to build the city. Therefore is the name of it called Babel; because the LORD did there confound the language of all the earth: and from thence did the LORD scatter them abroad upon the face of all the earth.

Page 61. " Caesar's wife "
Pompeia, Julius Caesar's second wife
Public DomainPompeia, Julius Caesar's second wife

This is a reference to the old saying, "Caesar's wife must be above suspicion."

Julius Caesar
Public DomainJulius Caesar
Caesar's wife, Pompeia, had not been unfaithful but had ended up in a situation where her fidelity could be questioned. Caesar divorced her as a result.

Page 61. " Not quite the act of a pukka sahib, I'm afraid. "

Pukka sahib is a Hindi phrase meaning "excellent gentleman."

British English borrowed a number of words from India during the time of British rule of the subcontinent (the British Raj) between 1858 and 1947.

Page 62. " I had my licence endorsed for a year. "

Having one's driver's license endorsed is part of the British penalty system for driving infractions. The system is explained here.

Page 64. " Landor got penal servitude for life and died in Dartmoor a year later. "

 Dartmoor Prison was built in the first decade of the 19th century. It is located in Princetown, Devon.

Today, Dartmoor houses mainly nonviolent and white-collar criminals, but in the 1920s when Landor was incarcerated there, it held some of Britain's worst offenders.

Page 64. " Illegal operation, was it? "

Lombard is making a veiled reference to abortion, which was illegal in England until 1967.

Page 65. " The Sister knew, of course "

"Sister" is the British term for a senior nurse.

It dates from the time when amateur medical and palliative care was routinely provided by nuns and other Christian women.  

Page 69. " In the midst of life we are in death "

Emily Brent is quoting from the Order for the Burial of the Dead in The Book of Common Prayer

The Book of Common Prayer is the book of services and prayers used in the Church of England, originally published in the 1500s.

Title page, Book of Common Prayer, 1662 version, printed 1762
Public DomainTitle page, Book of Common Prayer, 1662 version, printed 1762

When they come to the Grave, while the Body is made ready to be laid into the earth, shall be sung or said,

MAN, that is born of a woman, hath but a short time to live, and is full of misery. He cometh up, and is cut down, like a flower; he fleeth as it were a shadow, and never continueth in one stay. In the midst of life we are in death; of whom may we seek for succour, but of thee, O Lord, who for our sins art justly displeased? Yet, O Lord God most holy, O Lord most mighty, O holy and most merciful Saviour, deliver us not into the bitter pains of eternal death. Thou knowest, Lord, the secrets of our hearts; shut not thy merciful ears to our prayer; but spare us, Lord most holy, O God most mighty, O holy and merciful Saviour, thou most worthy Judge eternal, suffer us not, at our last hour, for any pains of death, to fall from thee.

Page 69. " No distinctive smell of Prussic Acid, probably Potassium Cyanide. It acts pretty well instantaneously. "

During both World Wars, Agatha Christie worked in a dispensary--a medical office that filled prescriptions, similar to a pharmacy. The knowledge she gained there of poisons served her well in her writing career.

Regarding her experiences in the dispensary during World War I, she wrote:

Later that year [probably 1914] I had flu badly, and after it congestion of the lungs which rendered me unable to go back to the hospital [to work as a nurse] for three weeks or a month. When I did go back a new department had been opened--the dispensary--and it was suggested that I might work there. It was to be my home from home for the next two years. . . . It was while I was working in the dispensary that I first conceived the idea of writing a detective story . . . and my present work seemed to offer a favourable opportunity. . . . Sometimes I would be on duty alone in the afternoon with hardly anything to do but sit about. Having seen that the stock bottles were full and attended to, one was at liberty to do anything one pleased except leave the dispensary. I began considering what kind of a detective story I could write. Since I was surrounded by poisons, perhaps it was natural that death by poisoning should be the method I selected. I settled on one fact which seemed to me to have possibilities. I toyed with the idea, liked it, and finally accepted it. Then I went on to the dramatis personae. Who should be poisoned? Who would poison him or her? When? Where? How? Why? And all the rest of it (An Autobiography, 235, 241-2).

Page 73. " Llewellyn, for the Crown, had bungled it a bit. "

"The Crown" would be prosecuting Edward Seton; the Defence would be arguing in his favor.