****SPOILERS**** The movie comes up with the bright idea of using the blood of wild animals and having it injected, by blood transfusions, into human beings. Thus combining that of the animals strength cunning and ability to hunt and take down game far bigger then itself, and only kill for food and survival, with that of the mindless and destructive mentality to kill and destroy for personal gratification and glory by man. Dr. Cameron, George Zucco, planned to create an army of mindless killers, half-man and half-beast, to be used against Hitler's vaunted Wehrmacht that would win the Second World War for the allies.
This mad idea had Dr. Cameron thrown out of the faculty of the university that he was a member of and declared insane as well as him being stripped of all his honors and accomplishments as a brilliant man of science. That left him a very bitter and vindictive man.
At his laboratory in his plantation home in the swamps the discredit Dr. Cameron was to put his experiments to a different use, against those who destroyed his professional career. Dr. Cameron has his hulking and powerful as well as harmless and simple minded handyman and gardener Petro, Glenn Strange, injected with wolf blood. That's how Dr. Cameron plans to do in those who made a monkey out of him as well as having him be the laughing stock of the scientific community.
George Zucco in one of his many mad doctor roles that he played in his long movie career is convincingly and perfectly insane as the mad Dr.Cameron. Glenn Strange is at the top of his game as the innocent and slow-witted Petro who's used by Dr. Cameron in his mad experiments as the instrument of revenge and murder.
The movie "The Mad Monster" was in some ways as insane as Dr. Cameron with his former faculty members, who should have known better, being so gullible as to fall right into the trap that he set for them. Coming over to Prof. Blaine, Robert Strange, home with Pedro Dr. Cameron tells the professor to inject Petro with a syringe of serum, wolf blood. This to be done after Dr. Cameron left and thus giving him an alibi was really brainless on the part of Prof. Blaine who was then killed by a transformed and wolf-man-like Petro. Later in the movie we have Prof. Fitzgerald, Gordon De Main, being invited to Dr. Cameron's plantation in the deserted swampland who should also have know better not to fall for Dr. Cameron's trap.
Prof. Fitzgerald having it out with Dr. Cameron about his mad monster experiments than, without thinking, has Petro, who lived at the Cameron plantation, put in his car to drive him back to town. Petro changed by a delay-action injection of wolf blood given to him by Dr. Cameron just before he left with Prof. Fitzgerald. Again Petro turned into a wolf-man and attacked Prof. Fitzgerald and made him drive off the road. Knocked out but alive Prof. Fitzgerald is saved by a group of townspeople who came to his rescue but is later killed by Dr. Cameron at his home, where he was taken for help, before he could wake up and tell the police what happened.
The ending of "The Mad Monster" was a bit too much with Petro as the wolf-man running amok at the Cameron home after it was hit by a lightning bolt and set on fire during a heavy thunderstorm with both Dr. Cameron and Petro perishing in the flames.
It was truly ironic that the movie "The Mad Monster" came up with the idea for the allies to use an army of wolf-men to fight against the German army. It was three years later in 1945 there were rumors that were taken very seriously by the allies that Hitler planned to use German guerrilla-type units to attack and battle behind the lines of the allied forces who were invading Germany; Those units were called by the German as well as the allied high command "WEREWOLVES".
