RICHARD FRIEDBERGSince the parameter b in (IS) approaches 1 as the electron energy approaches its maximum TFo-w" 2 /2m M , the relative sensitivity of /* decay to a and m v is different from that of processes (3) and (4). To take the example of the last paragraph but one, if a-0 and 7w"=1.6 MeV, the parameter b would affect both the energy spectrum and the asymmetry, for electron energies near the maximum, by an amount that might be observed by an improvement of existing measurements. But if 0=0.02 and m"=0, the parameter a 2 in (15) would be quite negligible. Thus, an improved measurement of the tail of the electron spectrum in ju decay might be combined with a measurement of the branching ratios for (3) and (4) to give an estimate of both a and m v .The preceding considerations are theoretical. In the immediate future, however, there is little hope of observing reactions (3) and (4) unless the branching ratio Rz/Ri is at the least 0.01. Such a large effect could not be produced by m v alone and could only be interpreted as evidence that a 2 >0. Indeed, it is known from the energy-momentum balance in ir-y. decay 6 that 6 W.