'This "theory" of tiny menaces causing disease was accepted in the 19th century; before that, no need for masks in the operating room'
germ theory
BIOLOG: This theory of tiny menaces causing disease was accepted in the 19th century; before that, no need for masks in the operating room
This "theory" of tiny menaces causing disease was accepted in the 19th century; before that, no need for masks in the operating room
This "theory" of tiny menaces causing disease was accepted in the 19th century; before that, no need for masks in the operating room
BIOLO"G"
germ theory
BIOLO"G"