On page 354 of the 6th edition of Microelectronic Circuits by Sedra & Smith under Current flow, the following statement is made;
Current will consist of two components: electrons injected from the emitter into the base, and holes injected from the base into the emitter.
According to wikipedia,
an electron hole is a conceptual and mathematical opposite of an electron.
If an electron is excited into a higher state it leaves a hole in its old state.
This is where it get confusing. Does the injection of holes from the base into the emitter imply a loss of electrons, i.e electrons injected from the emitter into the base or something else altogether?