The scientist who first studied the world of microscopic life was

Van Leeuwenhoek discovered "protozoa" - the single-celled organisms and he called them "animalcules". He also improved the microscope and laid foundation for microbiology. He is often cited as the first microbiologist to study muscle fibers, bacteria, spermatozoa and blood flow in capillaries

The scientist who first discovered the microbial life was Antony Van Leeuwenhoek. He is called as the Father of Microbiology