The tragical element in this otherwise ridiculous inconsistency lies in the fact that the knowledge of prudential checks is denied to the very class which most urgently needs such information. It is the poor alone who suffer acutely from the effects of over-population: it is they who feel the actual sting of want when the small wage is distributed over a large family-area. For the well-to-do there is no mystery concerning prudential checks. The family doctor will whisper discreetly into the ear of the wealthy matron whose quiver is sufficiently filled. Expensive medical works containing full instructions are at the command of those who can afford to buy them. Why should the poor be kept in ignorance upon a matter of supreme importance to them? Upon the subject of prudential checks the medical profession as a body has afforded little or no assistance. Here, as in many other matters, "doctors differ"; and no steps have as yet been taken to ascertain, by scientific investigation, the best method of preventing conception. The checks now to be described are of two kinds--first, those in which success depends upon self-control; and, second, those in which mechanical appliances are used. I. The practice of withdrawal immediately before the act of coition is completed obtains very extensively in France. This, the most ancient of known methods, is referred to in the Bible (Genesis xxxviii. 8-9). The efficacy of the check depends, of course, entirely upon the self-control of the husband, and failure is therefore always possible. It may be mentioned that this plan has sometimes been objected to on the ground of supposed injury to health; but no evidence has been adduced in support of the objection. On the other hand, Dr. C. R. Drysdale has ascertained by personal enquiry that 100 members of the medical profession in Paris "had only 174 children in all their married lives, or not two as an average.... The question of the effect produced upon the health of the parents by the use of the physical check of Genesis xxxviii. was discussed at the meeting of the International Medical Congress at Amsterdam in 1879; and two medical men of great distinction--MM. Lutaud and Leblanc--asserted distinctly that these practices of family physical prudence in France were in no way productive of ill-health to either conjoint. And, as they were universally made use of by the medical men of Paris in limiting their own families, it was very unlikely that such damage to health as had been spoken of would not have been noted and clearly described long ago if it existed in nature."