Simplify the following text for a Grade 10 native English-speaking person.
Original: â â These divisions between pro- and anti- animal testing groups first came to public attention during the brown dog affair in the early 1900s , when hundreds of medical students clashed with anti-vivisectionists and police over a memorial to a vivisected dog .
Simplified: â â The public first began giving its attention to the supporters and opposers of animal testing during the brown dog affair in the early 1990s . In the brown dog affair , hundreds of medical students and anti-vivisectionists and police argued over a memorial to a vivisected dog .