There are several objects, for the accomplishment of which persons are induced to simulate the existence of disease; such as, for obtaining military exemptions and discharges; or certain civil disqualifications; for the purpose of deriving parochial relief, or pecuniary assistance from benefit societies; or the comfortable shelter and retreat of an hospital; for exciting compassion and obtaining alms; for creating public interest and curiosity; for procuring release from confinement, or exemption from punishment; and, lastly, for the dishonest intention of recovering unjust compensation from some person selected for accusation, as the author of the pretended calamity. The subject has been very ably treated by different authors on Medical Jurisprudence, especially by _Mahon_ and _Foderé_, whose opportunities for observation during the severe operation of the conscription laws, must have been numerous and instructive; in our own country the work of _Dr. Hennen_, on the principles of Military Surgery, will be found to contain some very valuable information upon the detection of such impostures. The diseases which have been selected for the accomplishment of any of the purposes above enumerated are extremely numerous, although there are some few which may be said to be more generally preferred on such occasions. In general the medical enquirer will not have much difficulty in detecting such impositions; although there are cases where the investigation becomes a subject of extreme delicacy and importance, as in those of persons reporting themselves sick, and unfit for military service, or _Malingerers_, as they are technically called. It must be confessed that there is a degree of _eclat_ attending the detection of a fraud, which is very likely to lead the practitioner astray, by inducing him to attach undue importance to the supposed proofs of guilt; such cases have unfortunately occurred, and the innocence of the party has been compromised by the vanity of the inquisitor.