AT LIFE'S BORDERLINE.

This chapter provides information on viruses. The discovery of viruses was taken in 1892 when a Russian botanist named Dmitri Ivanovsky tried to figure out the cause of a disease that produced spots on tobacco leaves. It was until 1939 that a virus was actually seen using an electron microscope. Viruses are not cells nor are they made of cells. They infect cells of all kinds of living things. Scientists use observations to classify viruses such as their shape and what host they infect.