A veterinarian can often be involved in legal proceedings. In civil actions he can be plaintiff or defendant, e.g. if one of his clients refuses to pay or when he claims damages for malpractice. As far as criminal law is concerned he can also be accused of a wrong concerning the Act for the Protection of Animals or violation of professional discretion. In any trial he can be witness, competent witness or expert. Very often he has to appear in court as a competent witness; he has to make his special knowledge available to the judge in order to assist him in passing sentence, and it is, therefore, necessary for him to give an independent and impartial evidence.