In an early scene, the calendar date of "Saturday, March 16" is prominently displayed on Dr. Kravaal's wall. This is the actual 1940 calendar date, the year when the movie was filmed. However, later when the doctor and others are revived from a frozen sleep, they are informed that they have been frozen for ten years and that the year is now 1940. If that is the case, then the original calendar page on Dr. Kravaal's wall should have read "Saturday, March 15" which was the correct date in 1930.
When Dr. Mason uses the "standard" method of reviving Dr. Kravaal, it doesn't appear to be anything more than placing him near a fire and putting blankets on him. He asks his nurse for "more coffee," but it's unclear what he's doing with the coffee which would help him resuscitate the doctor as Kravaal is unconscious and can't be drinking it.