An ultrasound is a machine used by a sonographer (ultrasound specialist) to look into the human body, specifically areas of soft tissue. It is highly used during pregnancies to view the developing fetus. Ultrasound is also used to see the liver, gallbladder, lymph nodes, ovaries, testes, and many other parts of the body. The parts that make up the ultrasound are the probe, a central processing unit, transducer pulse controls, a monitor, keyboard, a storage device of some sort, and finally a printer. Ian Donald introduced the ultrasound in 1956 but many attempts and references were made before by several people. For example, a man named Galton created and produced a machine that was able to reach 40.000 GHz in 1880. Donald first used ultrasound to measure the diameter of a fetal head and was successful in doing so. He went on to develop this machine that is so widely used today with another man named Brown.