Biomedical electronics is a relatively new science. As a science it requires a basic knowledge of anatomy, chemistry, electronics, mathematics, physics and physiology. The utilization of this knowledge to design equipment for detecting biological changes, to improve the instruments of today and to evaluate these results by quantitative methods is the goal.

A review of the basic embryology concerning the fate of the aortic arches is described herein. Briefly, the first two pair appear and disappear early and are of no consequence. The third pair remain as the common carotid arteries. The fourth pair persist ~s different structures. The left arch becomes the arch of the aorta, and the right arch becomes the innominate artery. The fifth pair appear briefly then degenerate. The sixth develop into the pulmonary artery on the right side and the left becomes the ductus arteriosus until birth. When breathing begins muscular contraction closes the ductus arteriosus. The resulting structure is the ligamentum arteriosum.

Control of diseases in domestic animals is attempted for two main reasons: 1. To reduce reservoirs of disease transmissible to man, and 2. to produce livestock more economically.