510 Wisconsin Academy of Sciences, Arts, and Letters. 
the silver salt of a brompropionic acid by neutralizing with 
silver oxide. The reaction between silver oxide and brompro- 
pionic acid proceds with tremendous speed once the short period 
of induction is passed—hydrogen bromide is split off readily 
and silver bromide separates out quantitatively in a very short 
time. According to Senter, 14 a brompropionic acid, treated in 
water solution with silver nitrate, gives a reaction 17000 times 
faster than that of sodium hydroxide on the same acid. With 
silver oxide in place of silver nitrate, there is also undoubtedly 
a vast difference in speed between the two reactions. That we 
are dealing here with two totally different reactions is the opin¬ 
io of Senter, Burke and Donnan, 15 Euler 16 and others, who 
have attacked this problem from the physico-chemical stand¬ 
point. That different reaction products are formed remains to 
be rigidly established. 
Fisher and Scheiblef s Results and McKenzie's Contribution. 
We are now in a position to consider some results, which, when 
viewed in the right light, may turn out to be a reductio ad ab- 
surdum disproof of the whole Walden inversion. In the first 
place we may ask: Can Fisher’s explanation of the Walden 
inversion be followed out to give a completely harmonious sys¬ 
tem ? Ho. He has found that in the case of d valin (da 
aminoisovalerianic acid) a double inversion occurs i. e. an in¬ 
version both with nitrosyl bromide and ammonia, so that as a 
result of this cycle the original valin is regenerated. 17 In this 
case we may still believe, as Fisher first thought, that no inver¬ 
sion occurs with either reagent, since Fisher and Scheibler found 
that bromisovalerianic acid, treated either with potassium; hy¬ 
droxide or with silver oxide, 18 yielded the same hydroxy-acid. 
Here again we may have, of course, an inversion with both 
bases—indeed, unless we make such an assumption, the action 
of nitrous acid must also be considered abnormal, since 1 valin 
with nitrous acid gives the same oxy-acid as is obtained by the 
i4 Proc. Li. Ch. Soc. [1908] 24, 89. J. L. Ch. Soc. Dec., 1909, p. 1827. 
is Trans. L. Ch. Soc. 1904, p. 555. 
is Ber. 39, 2726-2734. 
it Ber. 41, 889. 
is Ber. 41, 2891. 
