Principle: General rule is that it is for the plaintiff to prove negligence of the defendant. But if the thing causing the injury is under the control of defendant and injury is such as would not occur without negligence, law presumes negligence.
Facts: While performing a surgery for the removal of stones from the kidney of 'A', Dr. 'B' left a mop inside the body of 'A'. 'A' suffered acute pain and has to be operated again for the removal of the mop.
'A' sues Dr. 'B' for damages.