The challenges of either party for cause need not all be taken at once, but they must be taken separately, in the following order, including in each challenge all the causes of challenge belonging to the same class:
1. To the panel.
2. To an individual juror for a general disqualification.
3. To an individual juror for implied bias.
4. To an individual juror for actual bias.
R.L.1910, § 5868.