This question of physical diagnosis leads them into a severe critique of Tardieu. Their polemic attacks each of the points which he attempted to establish. I must content myself by referring to the passage of their work which deals with the important topic.[16] Suffice it here to say that they reject all signs as worse than doubtful, except a certain deformation of one part of the body, which may possibly be taken as the proof of habitual prostitution, when it occurs in quite young persons. Of course they admit that wounds, violent abrasions of the skin, in certain places, and some syphilitic affections strongly favour the presumption of a criminal act. Finally, after insisting on the insecurity of Tardieu's alleged signs, and pointing out the responsibility assumed by physicians who base a judgment on them, the two Germans sum up their conclusions in the following words (p. 178): "It is extremely remarkable that while Tardieu mentions 206 cases, and communicates a select list of 19, which appear to him to exhibit these peculiar conformations of the organs, he can only produce one single instance where the formation seemed indubitable. Let anyone peruse his 19 cases, and he will be horrified at the unhesitating condemnations pronounced by Tardieu." The two notes of exclamation which close this sentence in the original are fully justified. It is indeed horrifying to think that a person, implicated in some foul accusation, may have his doom fixed by a doctrinaire like Tardieu. Antipathy and ignorance in judges and the public, combined with erroneous canons of evidence in the expert, cannot fail to lead in such cases to some serious miscarriage of justice. Passing from the problem of diagnosis and the polemic against Tardieu, it must be remarked that Casper was the first writer of this class to lay down the distinction between inborn and acquired perversion of the sexual instinct. The law does not recognise this distinction. If a criminal act be proved, the psychological condition of the agent is legally indifferent--unless it can be shown that he was clearly mad and irresponsible, in which case he may be consigned to a lunatic asylum instead of a jail. But Casper and Liman, having studied the question of sexual maladies in general, and given due weight to the works of Ulrichs, call attention to the broad differences which exist between persons in whom abnormal appetites are innate and those in whom they are acquired. Their companion sketches of the two types deserve to be translated and presented in a somewhat condensed form.[17]