This singular development is owing, probably, to a sympathetic connection between the uterine organs and certain parts of the brain, and large nerves in the neck. _Suppression of the Menses_ is one of the strongest presumptive signs of pregnancy that can be observed, but does not always _accompany_ it, and frequently arises from other causes. In the great majority of cases, it is true, the menses cease to flow, immediately conception occurs; sometimes they will continue for one or more periods after, and occasionally during the whole time of gestation, even up to a few days before delivery. This, however, is a very unusual occurrence, and the stoppage of the menses is by no means so strong a sign that pregnancy _has_ occurred, as their continuance is that it has _not_. Some females are always irregular, so that pregnancy makes little difference, and in them of course these signs are even less to be depended upon than usual. There have cases been known even of women who have conceived without having _menstruated_, and of others who never menstruated except when they were pregnant; and it is not at all unusual to see others who will conceive while nursing, and never menstruate between the two pregnancies. Therefore we can only say that the menses _usually_ stop when conception occurs, and that their continuance is strong evidence that it has not occurred, but still both signs may fail. It is also proper to remark that several medical men have advanced the opinion that the discharge which appears during pregnancy is not the menstrual fluid, but real blood. It has however been accurately examined, and found in no respect to differ from the usual discharge. In my own opinion there is no doubt but that some females really do menstruate while pregnant.