that secrecy is to be observed constitutes the matter of an onerous contract and binds more strictly than either a natural or a promised secret. Such are secrets of office which officials of all sorts become aware of in the execution of the duties entrusted to them; professional secrets of doctors, lawyers, priests, and others, who are consulted as experts by people in doubt or difficulty; as well as all others which are entrusted to any person under the express or implied condition of secrecy.
2. The obligation to observe a natural secret will cease after the secret has become public property. The party whose secret it is may sometimes be reasonably presumed not to be unwilling that the matter should be communicated to another, as, for example, to somebody who can and who will be of assistance to him. If the public good requires that the secret should be made known in order to prevent public wrong, the obligation of secrecy will cease, for the public welfare is of greater importance than that of an individual. If serious harm threatens one's self or some other innocent person, or the party whose secret is in question, and the harm can only be averted by making known the secret, this will be allowed in the case of natural or promised secrets. The right of defence from impending evil prevails over that of natural and promised secrets.
Even the obligation of the third class of secrets will cease when they cannot be observed without serious harm to the public weal. The natural law, however, which requires that people should be able to consult others in their difficulties in all security, demands that this class of secret should be observed in the case when even serious harm threatens some innocent person, unless he whose secret is in question is the cause of the impending evil. Thus, if I know as a professional secret who is the real culprit in the case of a crime wrongly imputed to an innocent person, I may disclose the real culprit if by some special means he caused the false accusation of the innocent person, otherwise I must keep the secret. It is a disputed point among theologians whether I am bound to observe a secret at the peril of my life when it was entrusted to me under that express condition, some maintaining that no one can pledge his life in that way, others more probably holding the contrary. Whether or not I am bound at my own serious loss to keep a secret entrusted to me under the condition of secrecy depends to some extent on circumstances. Sometimes I cannot be supposed under the circumstances to
