Thicker than Water was the final short film starring Laurel and Hardy. Directed by James W.Horne, produced by Hal Roach, and released in 1935 by MetroGoldwynMayer, the short also features James Finlayson and Daphne Pollard in supporting roles.
Mrs. Hardy then causes serious injuries to Ollie when she hits him over the head with a frying pan, requiring him to be rushed to hospital for a blood transfusion. The doctor conscripts Stan to be the unwilling blood donor what do you think I am, a blood worm?. During the transfusion, too much blood is pumped out of Stan and into Ollie, requiring some of the blood inside Ollie to be pumped into Stan. But too much blood gets pumped back into Stan, requiring another reversal, and so forth ... until the transfusion machine explodes. This sets up the climactic sight gag when Laurel and Hardy exit the hospital they appear to have morphed into each other. Ollie is minus his toothbrush mustache and wearing Stans hat and bowtie, while Stan is wearing Ollies hat, necktie and mustache. The two comedians proceed to do spoton imitations of each others mannerisms. Ollie mimes Stans famous befuddled head scratch while an exasperated Stan twiddles his tie in response and delivers Ollies signature catchphrase, Heres another nice mess youve gotten me into in Hardys dubbed voice. Ollie reacts by breaking into Stans trademark cry for the comic fadeout. And after they said their goodbyes to the doctors as they leave the hospital, Oliver as Stan told Stan as Oliver Wait a minute, I forgot something And it was pulling the end title screen.At one point in the film, Laurel and Hardy drag the next scene into the frame from offcamera. This effect was achieved with the opticalprinting device known as a wipe. ........
Source: Wikipedia