who was this person?
He was a French microbiologist.
Charles Chamberland
was a French microbiologist 
what is introduction to viruses? It is a tiny infectious agent that reproduces inside the cells of living hosts. who discovered this? Charles Chamberland
wiki:10710182
Charles Chamberland [SEP] Introduction
Charles Chamberland (12 March 1851 – 2 May 1908) was a French microbiologist from Chilly-le-Vignoble in the department of Jura who worked with Louis Pasteur. In 1884 he developed a type of filtration known today as the Chamberland filter or Chamberland-Pasteur filter, a device that made use of an unglazed porcelain bar. The filter had pores that were smaller than bacteria, thus making it possible to pass a solution containing bacteria through the filter, and having the bacteria completely removed from the solution. Chamberland was also credited for starting a research project that led to the invention of the autoclave device in 1879.