), Violacee, Purneracer, Caricacee, ‘Thymelacee, Lythracee, 
=z Mitlegindicas, Cone inate, Warbenenee, Labiate, Sbiandcoe: Barat hulisiaeee 
- Aeanthacee, Rubiacee, Caprifoliacee, Valerianacee and Composite as well as with some 
~ of unknown-botanical origin. Besides, there are several additions, an index of the 
SS NGalants yielding essential oils, classified according to the N.O., and a general index. 
_ The volume contains 51 illustrations in the text, 5 maps and a table of curves. The 
- number of essential oils dealt with has risen in the second edition from 422 to 952, 
‘ As the 8). volume of the collection “Chemie in Hinzeldarstellungen”, edited by 
Prof. Dr. Julius Schmidt, a monography of the coumarins has been written by 
__H. Simonis*), in which the author has compiled everything written on these bodies 
up to the end of 1915. It is self-evident that principally coumarin derivatives are dealt 
with which are of little or no interest for our special domain, but the coumarin itself, — 
_ $0 important for our industry, is discussed in detail too. Many interesting particulars 
referring to the history of coumarin are given. It was discovered by Vogel, in 1820, 
_in the Tonka beans, the seeds of Dypteryx odorata or “cowmarouna”. In the beginning, 
it is true, it was taken for benzoic acid, until Guibourt and later on Boullay and- 
- Boutron-Charlard (1825) recognized the peculiarities of the “Tonka camphor” and 
questioned its identity with benzoic acid. The first publications occupy themselves 
principally with the occurrence in, and the production from, different plants. Some es — 
; - authors gave Ci)H,O2, others CyH;O2, as formula based on the results of their analysis. 
_ The correct composition, Cy,H;O2, was recognized in the middle of last century by 
Gerhard and Bleibtreu und likewise by Dumas. The indications of the m. p. differ = 
= considerably, 40, 50, 120° and other figures being given; the correct value of 67° 
was only found in 1862 by Zwenger and Dronke. At that time, there still existed a as 
_ complete uncertainty as to the chemical constitution of coumarin, and even after Perkin © 
had carried out its synthesis, in 1868, 7. e. nearly half a century after Vogel’s discovery, 
'- the explanation of the structure was at first incorrect. Perkin was able to state already & Efi 
at the time that coumarin is only a link in a series of homologous bodies that may 
-- be prepared from the sodium compound of salicylaldehyde and the homologous acid 
anhydrides. He obtained in this way such a series of homologous coumarins, which 
he designated according to the anhydride used, and investigated the propionic, butyric, 
and valeric coumarins. Perkin first took the coumarin synthesized by himself for a 
mixture of acid radicals, consisting in acetylo-“diptyl”, CH;CO-C,H;0. The correct 
formula was established by Fittig about 1870 as that of an hydroxy-cinnamic anhydride, 
which view has been confirmed by later investigations. Perkin’s coumarin homologues 
_ could then be explained as methyl, ethyl, §., coumarins. In the section “Characteristics 
of coumarin” it is put forth that several of the coumarin derivatives are of general 
or scientific interest and partly occur in nature, such as umbelliferone (7-hydroxy- 
coumarin), citropten or limettin (5,7-dihydroxy-coumarin monoethyl ether), bergaptene 
ee tzans methyl ether), $c. The occurrence of coumarin in nature, 
_ the various synthesis and the physical and chemical properties are discussed in detail. 
Besides, the monography contains a comprehensive review of the coumarin derivatives, 
the number of which is so considerable that one might speak of a coumarine series 
the same as of a benzene series. Taking into consideration that coumarin consists 
- 
41) Prof. Dr. H. Simonis, Die Cumarine, eee 1916, 298 pages. Price -—# 12.— in paste, -% 13.— 
bound in linen. 
