512 Wisconsin Academy of Sciences , Arts , and Letters. 
COOH 
HC-OH 
ch 2 oh 
d glycerinic 
which is in beautiful harmony with the system proposed by 
Rosanoff. 22 Fisher and Easke succeeded in converting 1 serine 
into d alanine, 23 which in turn by treatment with nitrous acid 
gave d lactic acid. 24 We have, therefore, a rigid demonstration 
of the configuration of the whole series of tbe C 3 optically active 
acids, providing of course, tbat all the exchanges used in this 
proof take place normally. 
Fisher seems to be about to attack this problem from an en¬ 
tirely different point of view. Making use of Guye and Crum 
Brown’s hypothesis i. e. by simply determining the effect of var¬ 
ious substituting groups on the absolute rotation of a large 
number of organic compounds and taking account also of the 
relative position of the various groups, one may ultimately be 
able to calculate the rotation produced by a body of a given 
configuration. Providing no other side products were formed, 
we would have complete information regarding the changes 
taking place with optically active bodies as soon as we had de¬ 
termined the rotation of the product. The exact trend of Fish¬ 
er’s future work on the Walden inversion is hard to determine— 
his last paper on propyl, isopropyl cyanacetic acid 25 seems to 
be in the direction indicated here. To attain results of general 
significance along this line will involve, however, a very consid¬ 
erable amount of tedious work, since the elimination of the 
effect of the solvent upon the absolute rotation of various sub¬ 
stances is a matter of extreme difficulty. Unfortunately, all of 
our pure organic bodies can not be studied in the form of oils. 
We shall now consider some results in another series which 
may be interpreted on the basis of a double inversion. Short 1 " 
after Fisher’s first paper was published in March 1907, M 
Kenzie, an English chemist, announced some experimental i 
22 j. Am. Ch. Soc. [1906] Vol. 28, p. 118 footnote. 
23Ber. 40, 3717; Ber. 41, 893. 
24 Ber. 40, 1051. 
25 Ber. [Sept. 1909] 42, 2981-2989. 
