  I use a microscopic calculation of the weak capture process
3He(\mu^{-},\nu_\mu)3H, to extract and constrain the weak form factors of the
nucleon, particularly the induced pseudo-scalar, and the second-class currents.
The induced pseudo-scalar form-factor is found to agree with the prediction of
chiral perturbation theory. The constraint found on the conservation of vector
current (CVC) hypothesis is the tightest to date.
