EL 
77 
August 12, 1886] 
clearly explained in Mr. Pendlebury’s book on lenses, 
but that does not include other parts of the subject, and 
is somewhat needlessly long. 
The book concludes with an account of some simple 
optical instruments, dispersion and achromatism, and the 
geometrical theory of the rainbow. 
OUR BOOK SHELF 
New Commercial Plants and Drugs. By T. Christy, 
F.L.S., &c. No. 9. (London: Christy and Co., 
1886.) 
THIS pamphlet of 73 pages treats for the most part of 
medicinal products, though some consideration is also 
given to fodder and food-plants, essential oils, india- 
rubber, and various others. The first article is devoted 
to the Doundake (Sarcocephalus esculentus), a West 
African Rubiaceous plant, which has attracted some atten- 
tion of late in cases of nervous paralysis. The root has 
been analysed by Messrs. Heckel and Schlagdenhauffen, 
and their analysis is given together with a reproduction 
of the two plates which accompanied their paper. Two 
new perfume oils come under consideration, namely, from 
Eucalyptus staigeriana and Backhousia citriodora. The 
first is a Queensland tree, and is known as the lemon- 
scented iron bark. The odour of the leaves is said to be 
exactly like that of the lemon-scented verbena, and the 
oil yielded by them is identical in fragrance with that 
from Andropogon citratus, or lemon-grass oil, which is 
imported into this country both from Ceylon and Singa- 
pore, where the plants are very extensively cultivated. 
Mr. Christy says that “the odour of the oil of this tree 
is quite different from that of Eucalyptus citriodora, 
which resembles, and might be substituted for, citronella 
oil, so extensively used for perfuming soap.” The Back- 
housta oil is described as being like that of Lucalyptus 
staigeriana, and upon being tested for scenting soaps 
it was found to answer well, and would probably find 
a ready market in this country if it could be imported 
at a price to compete with ordinary verbena oil. It might 
realise Is. 4d. to 2s. per pound. 
The Kava root (Piper methysticunt) of the Fiji Islands, 
which is so well known for the disgusting ceremonies 
which, in former times perhaps more than the present, 
accompanied its preparation, has of late years been intro- 
duced amongst us for its medicinal properties. The active 
principle of the Kava root appears to reside in a resinous 
substance extracted with alcohol. Froma series of experi- 
ments it seems that this principle is a substance of very 
great importance as a local anzesthetic, but that in larger 
doses it produces a scaly affection of the skin. From the 
Kava root a spirit or liqueur has been distilled, and this 
under the name of Yagona is on sale at the refreshment 
bars of the present Colonial and Indian Exhibition. 
Another new drug which probably has a future before 
it is the Kombe of Central Africa (Strophanthus hispida 
or S. Komébe) which has been proved to be of consider- 
able value in affections of the heart. The first communi- 
cation relating to the physiological action of this drug was 
made by Prof. Fraser to the Royal Society of Edinburgh 
in 1870, which was followed in 1885 by a more elaborate 
paper at the Cardiff Meeting of the British Medical Asso- 
ciation. There seems, however, even after this lapse of 
time to be a difficulty in obtaining the seeds in quantity, 
or even the right species, several forms having been 
introduced from the Gold Coast, Sierra Leone, and 
other parts of Africa ; the chief difference lies in the seed, 
some forms of which are covered with long, fine silky 
hairs. 
Mr. Christy’s pamphlet, like its predecessors, is a 
useful record of newly introduced and useful plants. 
NATURE 235 
Heidelberg gefeirt von Dichtern und Denkern seit fiinf 
Fahrhundesten. Herausgegeben von Albert Mays. 
(Heidelberg, 1886.) 
Iv was a happy thought of the compiler of this volume 
to collect and publish on the five hundredth anniversary 
of the foundation of the University of Heidelberg a 
selection of what has been written about the city and the 
University by eminent men of various nations at different 
periods of time. A collection of all that has been written 
about the ancient city and its lovely situation would, 
Herr Mays says, fill a respectable library, for besides 
histories in verse of the Palatinate and its capital there are 
innumerable tales, novels, and the like based on incidents 
in its history,and lyrical and historical poems on Heidelberg 
by the hundred. In making a selection from this vast mass 
of matter, the compiler has only retained poems or de- 
scriptions which are of special poetical or literary value, 
or those which are of special interest on account of the 
author, or, finally, those which exhibit some special 
originality or peculiarity. But even when thus winnowed 
a handy volume is left. Needless to say, the vast majority 
of the writers are German;.there are a few English, and 
one American (Longfellow) The list commences with an 
extract from the Bull of Pope Urban VI. of October 23, 
1385, authorising Prince Rupert to found the University. 
This is followed by extracts from over sixty authors 
arranged chronologically. Herr Mays notices as a 
curiosity that not one of these is French. The English 
authors naturally dwell on the castle, “next to the 
Alhambra of Granada the most magnificent ruin of the 
Middle Ages,” rather more than on the University ; but 
indeed the German writers do the same. The book will 
show the good people of Heidelberg, if they lack such 
knowledge at this festive season, that they are citizens of 
no mean city. It should also prove an interesting 
memento to many in Europe and America who have 
passed a few years at the most impressionable period of 
their lives at the old University, which, with its sister at 
Bonn, has of late years drawn the British student away 
from Gottingen. 
LETTERS TO THE EDITOR 
[Zhe Editor does not hold himself responsible for opinions ex- 
pressed by his correspondents. Neither can he undertake to 
return, or to correspond with the writers of, rejected manu- 
scripts. No notice is taken of anonymous communications. 
[The Editor urgently requests correspondents to keep their letters 
as short as possible. The pressure on his space is so great 
that it is impossible otherwise to insure the appearance even 
of communications containing interesting and novel facts.) 
Organic Evolution 
For some time I have much desired to direct the attention of 
your readers all over the world to the two very remarkable 
articles on Organic Evolution, by Mr. Herbert Spencer, which 
appeared in the April and May numbers of the Nineteenth 
Century. hope they will be separately published. They mark 
in my opinion a new departure in the Philosophy which has been 
built up by a certain school of writers on the Darwinian Theory. 
Let me explain what I mean. 
From the first discussions which arose on this subject I have 
ventured to maintain that the successors of Darwin have run 
quite wild from the teaching of their master—that his Hypothesis, 
even if completely true so far as it went, offered no adequate ex- 
planation whatever of the multiform and complicated facts of 
Organic Eyolution—that the phrase ‘natural selection” repre- 
sented no true physical cause, still less the complete set of causes 
requisite to account for the orderly procession of organic forms 
in Nature; that in so far as it assumed variations to arise by 
accident it was not only essentially faulty and incomplete, but 
fundamentally erroneous ; in short, that its only value lay in the 
convenience with which it groups under one form of words, 
highly charged with metaphor, an immense variely of causes, 
some purely mental, some purely vital, and others purely physical 
or mechanical. 
