This black and white photograph depicts a medical demonstration or lecture taking place in a room. The central focus is a large anatomical chart displaying the arterial system of the human body. A woman in a long white dress and a hat is shown injecting a substance into what appears to be a model or a person's arm. She is holding a syringe in her right hand. Around her are several men, dressed in suits and hats, observing the demonstration. Some are seated in chairs, while others are standing. One man is seated at a table, and another is leaning forward with a look of concentration. A full skeleton is visible to the left of the anatomical chart, and another anatomical illustration is on the right. The scene suggests a medical lecture or a demonstration of an injection technique. The caption at the bottom reads 'Fig. 16.-Injecting the Arterial System Through the Radial Artery.'