March 2, 1871] 
NATURE 
347 

The red line, which was so brilliant in the auroral displays of 
last October, is very rarely visible, and does not coincide with 
any line which I have observed. The first red line of the tube 
spectrum is Ho, due to a trace of residual moisture. 
I think it best to publish these imperfect results without more 
delay, in the hope that they may be corrected or confirmed 
by other observers, as I am unable at present to continue the 
research, Henry R. Procrer 
Royal College of Chemistry, Feb. 7 

Resemblances of Plants inter se 
Mr. BENNETT, in his very interesting review of Mr. Mivart’s 
**Genesis of Species” (NATURE, No. 66), refers to the close 
resemblance of an African Euphorbia and a South American 
Cactus” as an instance of ‘‘imitation,” and to ‘‘ the extraordi- 
nary resemblance of certain Conifers to flowerless plants” as 
“opposed to the theory of Natural Selection.” 
Neither example seems to be well chosen. In every case 
of supposed ‘‘mimicry” or ‘‘ imitation,” the question first 
arises, whether the resemblance between different organisms be 
or be not referable to similar conlitions of life. Nobody will 
think a dolphin ‘‘imitates”” a fish, nor does a climbing Tamus 
“imitate” a Humulus. These are cases of similar adapta- 
tions, but wholly unconnected with anything like mimicry in 
its true sense. An aquatic mode of life, or climbing habits, 
will necessitate certain peculiarities of structure, and the in- 
fluence of an epidermis precluding evaporation will be the same 
in a Euphorbia as in a Cactus. The consecutive similarities of 
detail may without straining be referred to Mr. Darwin’s ‘‘ Cor- 
relations of Development.” 
There is still less cause for wonder in the resemblance of 
Conifers to flowerless plants, since it has been long ago shown 
by Hofmeister (‘‘ Vergleichende Untersuchungen,” 1851, cf. 
Sachs, Lehrbuch der Botanik, 1868, pp. 310 and 384) that there 
is a close affinity between Lycopodiacez and Conifers, in spite of 
the chief boundary line of our system running between them. 
The resemblances of these respective orders therefore are scarcely 
more ‘‘ extraordinary” than the resemblance of a Juncus to a 
grass, nor can I comprehend their bearing against the theory of 
Natural Selection. 
Mr. Bennett deals rather strongly with botanists in denying to 
them, with rare exceptions, ‘‘a philosophic spirit.” I cannot 
think this severe criticism to be applicable to the labours of Du 
Bary, Hofmeister, Sachs, Nageli, Schwendener, Pringsheim, and 
other contemporaries of ours (confining myself to my own country), 
labours alike distinguished by comprehensiveness of generalisa- 
tion and accuracy of detail. 
Did Mr. Bentham really come over to ‘‘the evolutionists” 
‘fonly within the last twelve months” ? I should consider that 
he expressed his full assent to the ideas of Mr. Darwin already 
in his addresses of 1868 and 1869. DD. W, 
Frankfort-on-the-Main, Feb. 21 
The Genesis of Species 
Ir this note should meet the eye of the writer on Darwinism 
in the Worth British Review for June 1867, I should feel greatly 
obliged if he would explain the following passage, quoted by Mr. 
Mivart in p. 57 of his ‘‘ Genesis of Species” :—‘* The advantage 
is utterly outbalanced by numerical inferiority. A million 
creatures are born; ten thousand survive to produce offspring. 
One of the million has twice as good a chance as any other of 
surviving ; but the chances are fifty to one against the gifted 
individual being one of the hundred survivors.” 
Is it an assumption or the statement of a fact that “one of the 
million has twice as good a chance as any other of surviving ?” 
and how are ‘‘ the hundred survivors” arrived at ? 
STUDENS 
Fertilisation of the Hazel 
In Nature for April 7, 1870 (vol. i. p. 583), Mr. Marcus 
Hartog stated, as the result of his observations, that the male cat- 
kins and female flowers of the hazel are not simultaneously deve- 
loped on the same twig, and that therefore a kind of quasi-cross- 
fertilisation necessarily takes place. Although convinced at the 
time that my observation did not tally with Mr. Hartog’s, it 
was then too late in the season to submit my impression to a 



practical test. During the past week I have closely observed 
the hazel bushes in flower, and have found on every bush which 
has come under my notice, the female and male flowers in a per- 
fect state of development on the same ultimate twigs, in close prox- 
imity to one another, the stigmas being frequently loaded with 
pollen-grains, apparently from the neighbouring catkin ; at all 
events there appears no provision of nature specially to. promote 
fertilisation from other bushes. We see in fact here a confirma- 
tion of the general law suggested in my paper in the first number 
of Narurg, on ‘‘ The Fertilisation of Winter Flowering Plants,” 
that when plants flower in the depth of winter, and at a time when 
no or few insects are about, self-fertilisation is the rule rather 
than the exception, or in the case of unisexual flowers, as near 
an approach to self-fertilisation as is possible under the circum- 
stances. ALFRED W. BENNETT 
Feb. 27 
Sanitary Tests 
Dr. LANKESTER recently pointed out in NATURE that the 
existence and spread of fever were mainly owing to popular 
ignorance and the neglect of physiological laws. Since the 
article referred to was written, a greater plague has followed the 
fever then prevailing ; and we are now told that Ireland is much 
better off than England—vaccination being there almost uni- 
versal. 
This state of things seems to me but a symptom of a more 
deeply-rooted evil, viz., the general neglect of physiological and 
sanitary science among the Azgher orders as well as the lower. 
In how many large schools are the laws affecting the human 
body and the relation of man’s frame to the destructive and con- 
structive elements which surround us systematically taught ? Are 
there any ? 
We talk of the gross ignorance and filthy habits of the poor ; 
but both their ignorance and their filthiness are often a part of 
the very conditions of their existence. Have we been faithful 
stewards in this great matter? 
Allow me to draw attention to the fact that, though Govern- 
ment has greatly facilitated and cheapened the acquisition of 
other branches of science, hygiene seems entirely omitted from 
the programme. But knowledge must descend from the higher 
to the lower levels. Ought not the heads of all public schools to 
undergo a compulsory examination in this subject? I could 
adduce instances where the greatest mischief has resulted from 
ignorance in such high quarters. 
Aigburth, Liverpool, Feb. 25 SAMUEL BARBER 
Morell’s Geometry 
IN my ignorance of the fact that there are two Morells of very 
different calibres in the literary world, I find, to my great regret, 
that I have done serious injustice to the ‘‘ widely-known” writer 
“on philosophy and grammar” and scholarly Mr. J. D. Morell, 
by attributing to him the authorship of the work on the 
‘* Essentials of Geometry,” whose appearance I was compelled 
to notice so unfavourably in last week’s NATURE. Pray give 
immediate publicity to this confession of error on the part of 4 
March 1 THE REVIEWER 

Algaroba 
AT p. 313 of NATURE (February 16) is a paragraph on the 
use of the Algaroba in the province of Catamarca, Argentine 
Republic, in which it appears to me the writer has confounded 
two or more plants. Algaroba is a name applied to Ceratonia 
siliqua, to several species of Prosopis in South America, and to 
Hymenea Courbaril in Panama. In Brazil the last-named plant 
in called Jatai, from which, I presume, the writer of the para- 
gragh in question has obtained his ‘* ymenea Courbaril- 
jetaiba.”’ The sweet fleshy pods of Prosopis dulcis, a tree widely 
spread over Southern and Central America, are used for feeding 
cattle, and several other species are employed for a like purpose in: 
different parts of the tropics ; it is therefore more than probable 
that P. dulcis is meant instead of Hymenea Courbaril. More- 
over, the pods of this latter are very thick and woody, and would’ 
not be easily ‘‘ pounded in a wooden mortar ;” and the tree 
cannot be well described as growing ‘‘to a height of forty feet, 
with wide-spread branches, and a rather slender stem,” when we" 
know that it frequently attains a hundred feet in height, and 
sixty feet in circumference, Joun R. Jackson 
Kew, Feb. 25 
