He observed that the agent multiplied only in cells that were dividing, but as his experiments did not show that it was made of particles, he called it a contagium vivum fluidum (soluble living germ) and re-introduced the word virus.
Observou que dito axente se multiplicaba só en células que estaban dividíndose, pero como os seus experimentos non mostraron que estaba feito de partículas, chamouno contagium vivum fluidum (xerme vivo soluble) e reintroduciu a palabra virus.