162 

whole inquiry, and which I have overlooked in Mr. Darwin's 
books if it is to be found there, is a discussion of the causes 
which produce sterility and those which favour fertility in races. 
He no doubt discusses with ingenuity the problem of the sterility 
of mules and of crosses between different races, but I have nowhere 
met with the deeper and more important discussion of the gene- 
ral causes that induce or check the increase of races. The facts 
upon which I rely are very common-place, and are furnished by 
the smallest plot of garden or the narrowest experience in breed- 
ing domestic animals. The gardener who wants his plants to 
blossom and fruit takes care that they shall avoid a vigorous 
growth. He knows that this will inevitably make them sterile ; 
that either his trees will only bear distorted flowers, that they will 
have no seed, or bear no blossoms at all, In order to induce 
flowers and fruit, the gardener checks the growth and vigour of 
the plant by pruning its roots or its branches, depriving it of 
food, &c., and if he havea stubborn pear or peach tree which has 
long refused to bear fruit, he adopts the hazardous, but often 
most successful, plan of ringing its bark. The large fleshy 
melons or oranges have few seeds in them. The shrivelled starve- 
lings that grow on decaying branches are full of seed. And the 
rule is universally recegnised among gardeners as applying to all 
kinds of cultivated plants, that to make them fruitful it is neces- 
sary to check their growth and to weaken them. ‘The Jaw is no 
less general among plants in a state of nature, where the indivi- 
duals growing in rich soil, and which are well-conditioned and 
growing vigorously, have no flowers, while the starved and dying 
on the sandy sterile soil are scattering seed everywhere. 
On turing to the animal kingdom, we find the law no less 
true. ‘Fat hens won’t lay,” is anold fragment of philosophy. 
The breeder of sheep and pigs and cattle knows very well that if 
his ewes and sows and cows are not kept lean they will not 
breed ; and as a startling example I am told that to induce 
Alderney cows, which are bad breeders, to be fertile they are 
actually bled, and so reduced in condition. Mr. Doubleday, 
who wrote an admirable work in answer to Malthus, to which I 
am very much indebted, has adduced overwhelming evidence to 
show that what is commonly known to be true of plants and 
animals is especially true of man. He has shown how indi- 
viduals are affected by generous diet and good living, and also 
how classes are so affected. For the first time, so far as I know, 
he showed why population is thin and the increase small in 
countries where flesh and strong food is the ordinary diet, and 
large and increasing rapidly where fish or vegetable or other weak 
food is in use; that everywhere the rich, luxurious, and well- 
fed classes are rather diminishing in numbers or stationary ; while 
the poor, under-fed, and hard-worked are very fertile. The facts 
are excceedingly numerous in support of this view, and shall be 
quoted in your pages if the result is disputed. This was the 
cause of the decay of the luxurious power of Rome, and of the 
cities of Mesopotamia. These powers succumbed not to the 
exceptional vigour of the barbarians, but to the fact that their 
populations had diminished, and were rapidly being extinguished 
from internal causes, of which the chief was the growing 
sterility of their inhabitants. 
The same cause operated to extinguish the Tasmanians and 
other savage tribes which have decayed and died out, when 
brought into contact with the luxuries of civilisation, notwith- 
standing every effort having been made to preserve them. Ina 
few cases only have the weak tribes been supplanted by the 
strong, or weaker individuals by stronger ; the decay has been 
internal, and of remoter origin. It has been luxury and not 
want ; too much vigour and not too little, that has eviscerated and 
destroyed the race. If this law then be universal both in the 
vegetable and animal kingdoms, a law too, which does not 
operate on individuals and in isolated cases only, but universally, 
it is surely incumbent upon the supporters of the doctrine of 
Natural Selection, as propounded by Mr. Darwin, to meet and to 
explain it, for it seems to me to cut very deeply into the founda- 
tions of their system. If it be true that, far from the strong sur- 
viving the weak, the tendency among the strong, the well fed, 
and highly favoured, is to decay, become sterile, and die out, 
while the weak, the under-fed, and the sickly are increasing at 
a proportionate rate, and that the fight is going on everywhere 
among the individuals of every race, it seems to me that the 
theory of Natural Selection, that is, of the persistence of the 
stronger, is false, asa general law, and true only of very limited 
and exceptional cases. This paper deals with one difficulty only, 
others may follow if this is acceptable, 
Deiby House, Eccles Henry H. Howorrn 


NATURE 

| Fane 29, 1871 

Ocean Currents 
Mr. Proctor concludes his letter on Ocean Currents, in 
Nature for June 15, with tle remark that in theories respecting 
oceanic circulation ‘*the vast distance separating the Polar from 
the Equatorial regions must not be overlooked.” Will you 
allow me to point out to him that in the experiment he suggests, 
that vast distance is entirely overlooked ; that, in fact, any such 
experiment, with whatever difference of detail it may be per- 
formed, whether in his cylinder or in Dr. Carpenter’s trough, in 
no way illustrates the natural condition of things, and in no way 
tends to answer that objection to the ‘‘temperature” theory of 
currents which is founded on the infinitesimal nature of the 
thermometric gradients. The difference of temperature between 
Arctic and Equatorial water is about 50° F., or 1° F. in 100 
miles; or, reducing it to smaller units suitable for an experi- 
ment, is godsou Of a degree in one foot; this, if the experi- 
mental trough is five feet long. or if the cylinder is ten feet in 
diameter, gives an extreme difference of yz,5y, Of a degree of 
Fahrenheit’s scale. Can such a difference be represented in any 
experiment? I think not; but no experiment which shows 
a much greater relative difference can be accepted as satisfactory ; 
for it is the infinitesimal nature of the thermometric gradient 
existing in the ocean that constitutes the physical objection to the 
temperature theory. There are other objections which I will 
not allude to now; but it is manifestly no answer to this one 
objection to show that under certain other circumstances—which 
bear no resemblance in degree to those of nature—hot water and 
cold will establish a circulation. I, for one, have, for a good 
many years, been perfectly well aware that they will ; but I doubt 
if it has ever been shown that a sensible motion will result from 
a thermometric gradient of gycsou Of a degree ina foot. 
J. K. LaucuTon 
Alpine Floras 
THE fact mentioned in last week’s NATURE of the absence of 
any Alpine flora on the Atlas Mountains, Morocco, though dis- 
appointing, is interesting. It seems to show that, during the 
glacial period, icebergs did not drift to the Atlas. This, how- 
ever, must have been from local causes only. Mr. Wallace found 
a European flora on a mountain in the Eastern Archipelago—I 
think in Borneo—which, most probably, must have got there 
during the glacial period. JosEPH JOHN MURPHY 
Old Forge, Dunmurry, Co, Antrim, June 19 
A Suggestion 
Is it possible that the following facts may account for the pre- 
sence of Z/astrus dolosus inthe Azores? At all events, I offer 
them as suggestive, and for the information of Messrs. Wallace, 
Godman, Murray, Crotch, &c. 
Lawrence Almeida, son of the first Portuguese Viceroy in 
India, was the first European known to visit the coast of Mada- 
gascar in the year 1506. The Portuguese circumnavigated the 
whole island within two years, and subsequently constantly 
anchored at it in their voyages to the East Indies. They also 
established a settlement on a steep rock on the bank of the river 
Franchere and near the village of Hatore, in the province of 
Anosi (¢.¢., at the south-eastern extremity of the island). The 
valuable timber, as ebony, as well as the rich dye-woods, would 
be well worth taking to Europe, and thus doubtless afforded a 
conveyance for living larval or pupal Elaters, without any rare or 
improbable concurrence of events, to the Portuguese islands in 
the Atlantic. Many of the extremely beautiful and attractive 
flowering shrubs and plants would also not improbably be for- 
warded to Europe by the same route, in which some Elateridze 
might find shelter. Is the lapse of 300 years sufficient to account 
for change of development ? S. P. OLIVER 
Southsea 


HYDROUS SILICATES INFHCTING THE 
POR:S OF FOSSILS 
R. T. STERRY HUNT directed attention some time 
ago* toa remarkable limestone of Silurian age from 
Pole Hill, New Brunswick, in which I had found the 
* Proceedings of the Natural History Society of Montreal, 
