80 NATURE 
[SEPTEMBER 18, 1913 
— SSS a ee 
of natural products. The constitution of rubber is 
approximately known; most of the alkaloids have 
been explored with a greater or less degree of com- 
pleteness; and now the study of starch,*? chlorophyll, 
and hematin (the non-proteid constituent of haemo- 
globin) °* has been taken up afresh during the last 
three years, with results which, in the case of the two 
latter, eclipse in importance and interest all that was 
previously known. In whatever direction we may 
look, there is the same evidence that we can take 
to pieces the most complicated structure which nature 
has devised, and by the aid of valency conceptions can 
fit the pieces into a formula which is an epitome of 
the chemical activities of the molecule. Again, in 
many cases the resources of our laboratories enable 
us to build up the structure thus displayed, and to 
establish the identity of nature’s product and our own, 
Nevertheless, the fact remains that all these syntheses 
leave untouched and unexplained the profound differ- 
ence between the conditions we find necessary to 
achieve our purpose and those by which the plant or 
animal carries on its work in presence of water and 
at a temperature differing only slightly from the 
normal. It is, of course, a well-known fact that an 
enzyme under the appropriate conditions can bring 
about the same chemical transformation of a substrate 
as is effected by the living cell from which it can be 
Separated; but our knowledge of these complex, ill- 
defined, nitrogenous organic compounds is relatively 
very meagre; they are difficult to purify, and their 
composition—apart from any question of structure— 
is largely unknown. Yet because Wahler chanced to 
discover that urea can be produced synthetically from 
an inorganic source the conclusion is not infrequently 
drawn that all chemical changes in living substance 
are brought about by ordinary chemical forces.*? 
Probably everyone present will concur in that view, 
but the assent, if given, can scarcely arise from a 
consideration of the facts, of which there is no great 
store. Where so little is known accurately, chemistry 
1s not on very safe ground if she infer the rest. 
What common basis of comparison exists between 
Wohler’s process and the metabolic changes by which 
urea is produced in the living body? What evidence 
have we that because an enzyme and an inorganic 
agent under different conditions give rise to the same 
end product, the driving force is the same, although 
the lines along which it is exercised are very different ? 
I think it is not the least of the many services which 
Prof. Meldola has rendered to chemistry, that he has 
given us this warning: “If we have gone so far 
beyond nature as to make it appear unimportant 
whether an organic compound is producible by vital 
chemistry or not, we are running the risk of blockad- 
ing whole regions of undiscovered modes of chemical 
action by falling into the belief that known laboratory 
methods are the equivalents of unknown vital 
methods.”’ °° 
I turn now to a no less interesting question than 
that involved in enzyme reactions, namely the wide 
distribution in plants and animals of single asymmetric 
°7 H. Pringsheim and H. Langshans, Ber. 1912, xlv, 2533, 
58 For summaries of Willstitter's and Marchlewski’s researches on chloro- 
phyll. and of Piloty's on hematin, of “Annual Reports on the Progress of 
Chemistry (Gurney and Jackson) rgrr, vili, 144-152; tora, ix, 165-172. 
59 “* Quite similar changes can be produced outside the body (#2 zx) by 
the emp!oyment of methods of a purely physical and chemical nature. It 
is true that we are not yet familiar with all the intermediate stages of trans- 
formation of the materials which are taken in by the living body into the 
Materials which are given out from it. But since the initial processes and 
the final results are the same as they would be on the assumption that the 
changes are brought about in conformity with the known laws of chemistry 
and physics, we may fairly conclude that all changes in living substance are 
brought about by ordinary chemical and physical forces."—Sir Edward 
Schafer, President's Address at the Dundee Meeting, British Association 
Keport, 1912. p. 9. 
60 R. Meldola, ‘The Chemical Synthesis of Vital Products ” (Arnold, 
1904), Pp. 7. 
NO. 2290, VOL. 92] 
substances which if synthesised in the laboratory 
would be produced as inactive mixtures of both asym- 
metric forms. It has been argued that the occurrence 
of racemic compounds in nature, although infrequent, 
is a proof that in the organism, as in vitro, they are in 
all cases the initial products from which, when 
separated into antipodes, one of the asymmetric com- 
pounds is utilised in the life processes and the other 
left. But whether this be the case, or whether only 
the one asymmetric form result from the synthesis, 
Pasteur firmly held the view that the production of 
single asymmetric compounds or their isolation from 
the inactive mixture of the two forms is the preroga- 
tive of life. Three methods were devised by Pasteur 
to effect this isolation, and in only one of them are 
living organisms—yeasts or moulds—employed; but 
Prof. Japp, in his address to this Section at Bristol 
in 1898, emphasised the fact, hitherto overlooked, that 
in the two others, nevertheless, ‘‘a guiding power [is 
exercised by the operator] which is akin in its results 
to that of the living organism, and is entirely beyond 
the reach of the symmetric forces of inorganic 
nature.’’ Hence, to quote again from his address, 
“Only the living organism with its asymmetric 
tissues, or the asymmetric products of the living 
organism, or the living  intelligence—with its 
conception of asymmetry, can [bring about the 
isolation of the single asymmetric compound.] 
Only asymmetry can beget asymmetry.” After 
an exhaustive review of the subject, Japp came 
to the conclusion that the failure to synthesise single 
asymmetric compounds without the intervention, either 
direct or indirect, of life is due to a permanent dis- 
ability, and although—as was to be expected—this 
conclusion was challenged,®’ the only ‘‘asymmetric 
| syntheses”’ effected since that time have been opera- 
tions controlled by the chemical association of an 
optically active substance with the compound under- 
going the synthetical change.** 
Recently the problem has assumed a more hopetul 
character. Ostromisslensky ** in 1908 made the re- 
markable discovery that inactive asparagine, which is 
not racemic but a mixture of the dextro- and laevo- 
forms in molecular proportion, gave a separation of 
one or other isomeride when its saturated solution was 
inoculated by a crystal of glycine—a substance devoid 
of asymmetry. Now Erlenmeyer claims to have 
achieved a true asymmetric synthesis by boiling an 
aqueous solution of inactive asparagine for sixteen 
hours, when by crystallisation part of the dextro-form 
separated in an almost pure state.° The theoretical 
conclusions which led to this investigation are of 
much interest because they raise afresh the question 
whether without displacement of the individual 
radicals, and apart from antipodes, more than one 
compound can exist, in the molecule of which two 
carbon atoms are united by a single linking.®° As an 
illustration, reference may be made to the malic-acid 
series, in which three optically active compounds are 
known, the dextro-acid, the laevo-acid, and Aberson’s 
acid.** In the laevo-series the three isomerides ob- 
tainable by rotation of one of the carbon atoms with 
its attached radicals relatively to the other would be 
61 F.R. Japp, ‘‘ Sterenche nistry and Vitalism. Presidental Address to 
Section B (Bristol), British Association Report, 189°, p. 826; cf. K. Pearson, 
Nature, 1808, lviii, 495; G. Errara; F. R. Japp. #rd., 616 ; Ulpiani and 
Condelli, Gasz. chim. ital. 1900, xxx [i], 344; Byk, Ber., 1904. XXXVil, 
4696 ; Heule and Haakh. Ber., 1908, xli. 4261 ; Byk, Ber., 1909, xlii, 141. 
® Cf inter alia, McKenzie, Trans. Chem. Soc., 1905, Ixxxvii, 1373. 
83 1. von Ostromisslensky, Ber., 1908, xli, 3035. 
64 E. Erlenmeyer, Biochem Zeitsch , 1913, lil, 439. 
8 Cf J. Wislicenus, ‘*Ueber die riumliche Anordnung der Atome 
in organischen Molekulen” (Leipzig bei S. Hirkel, 1889), 28; K. Auwers 
and V. Meyer, Ber., 1888, xxi, 791. 
66 J. H. Aberson, Ber., 1898, xxxi, 1432; P. Walden, Ber, r£99, 32, 
2720. 
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