OcroseEr 4, 1918] 
In Fig. 3 is a list of some typical symbols 
for different classes of compounds. A dot 
(e. g., in leucine) indicates an asymmetric 
earbon-atom and thus the optical active com- 
pounds are characterized. The long decor- 
ative design represents an octodeca-peptide or 
artificial peptone. Of the ring compounds 
mainly simple representatives have been se- 
lected, but some of the purin-bases at the 
bottom of the table (xanthin and derivates) 
show the simplicity of complex-rings. It will 
be noted that the different derivates are very 
plainly shown in their relationship, differing 
AMMONTA AMMONIUM  NEURTN 
SCIENCE 
CHOLINE 
335 
rangement of the atoms in the molecules. A 
ring of six atoms would be represented by a 
hexagon, and not by a square, one of five 
atoms as a pentagon and so on (compare, eé. g., 
xanthin). 
In certain cases nitrogen possesses a valency 
of five and in Fig. 4 the relationship of these 
symbols is shown. Also the use of the ordin- 
ary symbols in connection with organic sym- 
bols. S sulfur in thiophen, Cl= chlorine in 
chloroform. 
The writer has already employed the sys- 
tem in one of his classes with success and 
THIOPHENE CHLOROFORM 
apeeie ae OH cl 
cl—¢—eh 
NEce 
No 
NE Se 
Fic. 4. Pentavalent Nitrogen and Examples of other Elements. 
in that case only by the addition of one, two 
or three —CH, groups (crosses in the sym- 
bols). Hmoporphyrin, the mother substance 
of hematin of the hemoglobin of the blood, 
is an example of the more complex structures 
which recent investigations have disclosed. 
_ With the rapid progress in organic chem- 
istry and the structures of compounds becom- 
ing more and more complex, the need for a 
simple device of recording facts becomes ap- 
parent and I am indebted to the late Dr. 
Henry S. Denison, whose suggestions? on a 
“chemical shorthand” caused the working 
out of the present system of “organic sym- 
bols.” While the system is still in the pre- 
carious state of developmen‘, it is necessary 
to warn against indiscriminate use of the 
principles involved in constructing symbols. 
An indiscriminate application would lead to 
confusion and for this reason certain standard 
types of symbols must be established. These 
standard types must or should conform as far 
as possible to the theories concerning the ar- 
2 Denver Medical Times, Vol. 31, p. 360, 1912. 
found it a time- and space-saving medium in 
transmitting facts of organic chemistry toy 
students and hopes that the system may be- 
come of value to other scientists. 
Inco W. D. Hackx 
BERKELEY, CALIF. 
FRANK N. MEYER? 
Meyer was in the second year of his third 
great Middle Asiatic Exploration. His first 
trip of two years covered North China, includ- 
ing Mantchuria, in which province he walked 
1,800 miles. His second trip of three years in- 
cluded the Caucasus, Persia, Turkestan, east- 
ern Thibet, the middle districts of the great 
empire and Japan. His third trip was to have 
covered all the more southern portions of 
China likely to contain plants useful to west- 
ern agriculture. During these seven years 
which were full of strange adventures he made 
thousands of interesting observations, penned 
1 Drowned in the Yang-tsze-kiang, June 1, 1918, 
and buried in Shang-hai, China. 
