Three things

were said by Rabbi Elazar ben Parta

before the Sages

and they instituted his words:

regarding [a person in] a city under siege,

and regarding [a person in] a ship caught at sea,

and regarding one going to be judged [for a capital offence],

that they are presumed to be alive.

However, a city taken by siege,

and a ship lost at sea,

and one walking out to be executed,

we give them the stringencies of the living

and the stringencies of the dead,

the daughter of a non-cohen married to a cohen

and the daughter of a cohen married to a non-cohen

may not eat terumah.

and falls ill

such a person may send it with another.

But if he [the husband] said to him

"get from her for me a certain item"

he may not send it with another

as he [the husband] does not want his asset 

in the hands of someone else