<正> Animal experiments demonstrated that severe acoustic trauma of themiddle and inner ears occurred after cannonade explosion within a dis-tance of about 8 metres.Among the 60 ears of 30 guinea pigs

57 showedrupture of eardrums

32 had destruction of ossiele-chains

while 47 hadaccumulation of blood and exudates in the middle ears;a gradient of in-jury of the cochlea was also observed

minimal damage occurred in 3

increased in 41

and maximal in 16.The injuries occurred chiefly in thefirst and second turns

but the third and fourth turns were also involvedin 21.The results coincide with the clinical audiometry curve of thepatients who suffered from explosive acoustic trauma.