The wedding of Dr. Kildare and nurse Mary Lamont is fast approaching, and Mary's brother, Doug (Robert Young) has come for a visit. He has drawn up plans for a philanthropic concern that needs the backing of a rich person, and so he has come to New York for two reasons - to meet his future brother-in-law and also to ask Dr. Kildare to introduce him to a rich man who is indebted to Kildare. During the visit, Kildare notices that Doug seems to be hearing things followed by a period of extreme energy and confidence. For reasons that are beyond me, Kildare thinks that this behavior could amount to some dread disease and won't stop until he uncovers said dread disease. Complications ensue.
The disease that is suspected is epilepsy, and as with most illnesses mentioned in this series, it is given an excessively bad rap. It is said it leads to insanity unless the person lives a very calm uneventful existence, it is said that the person eventually becomes an invalid, and because it is often inherited, it could mean that Mary has it too. But wait, wouldn't that mean that their parents would have it too, that it wouldn't just suddenly crop up in Doug and Mary? This is never mentioned.
So the diagnostic/treatment portion of this film is a bit of a mess, but then I'd expect that from a film that is 85 years old. The entries on melanoma and diabetes were all wrong medically too, but they were still enjoyable films. The key to its enjoyability is the consistency of the supporting characters - Molly Bird, Nat Pendleton as lovable but strong as an ox Joe, Nell Craig as the persistently terrified Nurse Parker, and Marie Blake as Sally the hospital receptionist and switchboard operator.