A paper test for occult blood in faeces using ortho-dianisidine.

The capacity of the refrigerator' is approximately 44 cubic feet. The cabinet is insulated throughout with 4 inches of compressed cork, encased outside with painted plywood and inside with stipple-glazed asbestos sheeting. Internal lighting is provided with automatic operation on opening and closing the doors. Cooling is by means of a Prestcold plate type of evaporator and serviced by a Prestcold superprasmatic condensing unit with a i H.P. integral electric motor. Air circulation is controlled by a fan drawing air over the evaporating unit. The fan is cut out by door-operating switches. An audible buzzer and warning light operate should the air temperature fall below 40 or rise above 7°. This system operates by independent batteries. The blood temperature is recorded by a Bristol single-pen recorder with the thermometer placed in a standard 1-pint blood transfusion bottle containing glycerol.