When the male organ is covered by an indiarubber _French Letter_, condom, or Malthus sheath, a little bag with thin walls, there is no chance of the woman being impregnated if the bag be not torn. In all instrument-makers’ shops they are sold at from two to three shillings the dozen. One rather too large is to be preferred, for these bags contract if used more than once.
When the husband makes use of the French Letter, it must be unrolled, pushing it up not quite to the end, expressing with the hand the air bubbles which may remain in its cavity; the bottom may also be moistened inside with a little soapy water or saliva.
If, after using it, the French Letter be empty, it is evident that it must have been torn, in which case the wife should immediately use careful injections; but this may be too late.
One letter may suffice for several times; in this case, it must each time be carefully wiped off or washed and dried and inflated in order to remove the folds, and to see that it has not been torn; and lastly, it may be powdered with a little powder inside and outside. The best powder is that of lycopodium, which is obtainable at a cheap rate in druggist shops. After having powdered it, the French Letter may be opened by means of two fingers, and be rolled up again when required for further use.
The same French Letter should not be too often used, perhaps two weeks or six times, and it should not be too old, for in the lapse of time it loses its properties. Like all things made of indiarubber, it is well to keep it in a rather damp, cool place, and shield it from light or frost, it must not be touched by greasy substances, such as oil, fat, vaseline, paraffin, etc., nor with carbolic acid or other substances which act upon indiarubber.
There are also French Letters or condoms of gut, called _Skin Letters_, made from the cœcum of sheep. These are sold at higher prices, and are more durable and stronger than the indiarubber ones. They have the fault that they become somewhat hard after frequent use. They are not elastic, and therefore cannot be rolled up, so that they cannot be used if they are too narrow. Before use, it should be carefully examined against the light to see that it is not made of pieces glued together, which fall asunder as soon as the bag is moistened, and then it must be blown up gently to see that there are no holes in it. When good, it may be used for a month. Their employment is quite like that of indiarubber letters.