Negri performed extensive research in the fields of histology, hematology, cytology, protozoology and hygiene. He contributed to the development of bacteriology and protozoology in England, South Africa and Australia. On his retirement he was appointed Professor of Medical Protozoology at the University of London. Veterinary protozoology is focused on protozoas with veterinary relevance. From 1914 to 1915, she taught medical zoology and protozoology at UP. Protozoology is the study of protozoa, the "animal-like" (i.e., motile and heterotrophic) protists.