CHEMISTRY: JACOBS AND HnOELBERGER 
195 
ally appreciated, although it was discovered in 1893 by Schroder (Zs. 
physik. Chem., 11, 449). 
2. Another important use to which the general freezing-point-solu- 
bihty law could be put would be in settling the frequently discussed 
question as to whether racemates exist as such in the liquid state, and 
if so, to what extent. This question could be most certainly and defi- 
nitely decided for any given pair of optical isomers simply by determin- 
ing the freezing-point diagram for the system and applying the general 
law. The exact amount of racemate present in the liquid state and the 
manner in which it varies with the temperature could also be computed; 
for a solution composed of two optical isomers forms one of the most 
perfect examples known of an ideal solution, and the laws of such solu- 
tions would apply with great exactness over the whole range of concen- 
trations. In addition to the freezing-point diagram, the latent heats of 
fusion and the heat of dilution would also be needed in order to work 
out the problem completely. The main point which it is desired to em- 
phasize here is simply that the ideal solution laws are capable of giving 
a complete and quantitative answer to such a question as this, an answer 
concerning the correctness of which no reasonable doubt could be felt. 
MERCURY DERIVATIVES OF AROMATIC AMINES. I. STRUC- 
TURE OF PRIMARY AND SECONDARY p-AMINO- 
PHENYLMERCURIC COMPOUNDS 
By Walter A. Jacobs and Michael Heidelberger 
ROCKEFELLER INSTITUTE FOR MEDICAL RESEARCH, NEW YORK 
Presented to the Academy, February 17, 1915 
During the year 1902, the question of the structure of the mercury 
derivatives of the aromatic amines was the occasion of a polemic between 
L. Pesci^ and O. Dimroth.^ The former ascribed the complex structure 
(I) to the mercuriated primary and secondary amines (R = H or alkyl), 
while Dimroth advocated the simple monomolecular formula (II), 
basing his views upon argmnents which Pesci was unable to con- 
trovert. Subsequent workers have used the monomolecular formula 
R R 
1 
I 
CH3COOHN Hff NCH3COOH H— N— R 
/\ 
(I) HgOOCCHa (ji) 
