Page:Contraception; 1st ed. (IA in.ernet.dli.2015.94163).pdf/179

not as in B, where the rim is too thick and heavy and the conical portion C is too flat and small.

There are two interesting physiological reasons against too flat a cap, one depending on the characteristic of a good many women, namely, irregularity in the menstrual appearance, so that they may find themselves inadvertently wearing the cap at the commencement of the menstrual flow. A very small dome is then unsuitable; if the high domed type I recommend is used no anxiety need be felt, as it allows for the flow for several hours at least; a second reason for the high dome is found in some women of intense sex activity, in whom the orgasm gives rise to uterine secretions in some quantity, for which the large dome allows an exit. Furthermore with a large thin centre to the cap there is no risk of crushing the cervical canal, whereas the small hard central dome or the flat lens-shaped cap both tend to crush and interfere with the cervix. Moreover, the high thin central piece allows of invagination, if, as sometimes happens, the glans penis and the cervical os interlock at the time of passion (see p. 60). I know of no objection whatever to the high dome to counterbalance all these advantages, and can think of none.