— 99 — 
The importance of this synthesis lies in the fact that of the many 
camphor formulae proposed in the course of time, the one drawn up 
by Bredt in 1893, whose correctness was borne out by many im- 
portant facts, now appears to be finally established. As, according to 
Haller, camphoric acid can be converted into camphor, the com- 
plete synthesis of camphor has now been rendered possible by 
Komppa's work. 
In 1899, J. Klimont^) made an attempt to draw up aromato- 
phorous groups for the artificial and natural perfumes, and to discover 
the relationship between the chemical constitution and the odorous 
action. A. Bo lis 2) has inquired into the same subject. He expresses 
in the first place the opinion, that after the development which the 
chemistry of artificial perfumes has experienced during the last few 
years, a displacement of the natural products by those produced syn- 
thetically will follow, as has already been largely the case in the 
chemistry of colouring matters. The views laid down by the author 
on certain laws prevailing within the group of odorous substances, 
have in part already been expressed by Klimont. On the whole it 
must be said that the examples quoted are not by any means suf- 
ficient to deduce therefrom a definite relationship between the odour- 
intensity and the behaviour on boiling or the entrance of certain 
groups. The assumption that in nature only the aliphatic compounds 
of the iso-series occur, and never those of the normal - series , is in- 
correct; for, in addition to citral, citronellal, geraniol, bodies of the 
normal aliphatic series have often been discovered as intensive odorous 
matters in essential oils, — e. g., the normal octylic, nonylic, and 
decylic aldehydes, the normal octyl and nonyl alcohols, and also the 
normal amyl, heptyl, and nonyl methylketones. 
It is well known that by esterification of the alcohols and ether- 
formation of the phenols, important perfumes are formed, frequently 
of greater value than the individual components; but we must point 
out that this rule is also not without exceptions. With regard to the 
example quoted by the author, that salicylic aldehyde, which already 
possesses a good odour, has a much lower odour-intensity than its 
methyl ether, anisic aldehyde, it should be said that anisic aldehyde 
is not the ether of salicylic aldehyde, but of p - oxybenzaldehyde. 
A distinct relationship is further found in homologous series, where 
the similarity of odour is striking, especially between the members which 
stand closer to each other. 
^) J. Klimont, The synthetic and isolated aromatics. Vienna 1899. 
^ A. Bo lis, On the odour of organic compounds. Chemiker - Zeitung 28 
(1904), 61. 
7* 
