B.— CHEMISTRY. 59 
Although the yield was very small, it reached 42 per cent. when 
acetone was replaced by a salt of its dicarboxylic acid, which might 
easily arise from citric acid as one of the intermediate compounds used 
by plants in their synthetical exercises. 
Based upon this experiment, R. Robinson (1917) has developed an 
attractive explanation of the phytochemical synthesis of alkaloids, in 
which the genesis of a pyrrolidine, piperidine, quinunuclidine, or iso- 
quinoline group is shown to be capable of proceeding from the associa- 
tion and interaction of an amino-acid, formaldehyde, acetonedicarboxylic 
acid and the intermediate products of these, taking place under the 
influence of oxidation, reduction, and condensation such as the plant 
is known to effect. It would scarcely be fair to the resourceful skill 
embodied in this theory to attempt an abbreviated description of the 
methods by which molecules as complex even as those of morphine and 
narcotine may be developed. Ornithine (aé-diaminovaleric acid) is 
represented as the basis of hygrine, cusehygrine, and the tropine alka- 
loids, whilst the coniine group may spring from lysine ( ae-diamino- 
caproic acid). A particularly interesting application of these principles 
has been made with reference to the vital synthesis of harmine, which 
W. H. Perkin and R. Robinson (1919) represent as arising from a 
hydroxytryptophan as yet undiscovered; meanwhile they have shown 
that harman is identical with the base obtained by Hopkins and Cole 
on oxidising tryptophan itself with ferric chloride. Thus it may be 
claimed that Robinson’s theory represents a notable advance in our 
conception of these vital changes, and that by means of the carbinol- 
amine and aldol condensations involved fruitful inquiries into constitu- 
tion and the mechanism of synthesis will follow. 
The Nucleic Acids. 
Owing to the venerable position occupied by alkaloids in the sys- 
tematic development of chemical science, and to the success which 
has attended elucidation of their structure, many of us have become 
_¢allous to the perpetual mystery of their elaboration. Those who seek 
fresh wonders, however, need only turn to the nucleic acids in order 
to satisfy their curiosity. For in the nucleic acid of yeast the chemist 
finds a definite entity forming a landmark in the path of metabolic 
procedure, a connecting link between the undefined molecules of living 
protein and the crystallisable products of katabolic disintegration. 
Let us review this remarkable substance. With an empirical 
formula, C,,H,,O,,N,,P,, it has a molecular weight (1303) exceeding 
that of the octadecapeptide (1213) synthesised by Fischer (1907), 
although considerably below those of the penta-(penta-acetyl-m- 
digalloyl)-8-glucose (2136) produced by Fischer and Bergmann (1918). 
and of the hepta-(tribenzoylgalloyl)-p-iodophenylmaltosazone (4021) 
elaborated by Fischer and Freudenberg (1912). Nevertheless, its in- 
trinsic importance is transcendent. In the language of chemistry it 
is a combination of four nucleotides, linked with one another through 
the pentose molecule, d-ribose, which is common to each, and owing 
its acid character t6 phosphorie deid, also Common t6 thie component 
