200 
[April, 
The “ Species ” War Reopened. 
of the West Indies. There we have a marked insular fauna, 
almost no mammals that are indigenous (although cattle and 
goats have flourished and become feral under European 
auspices), but an enormous profusion of land-shells, surely 
as difficult to transport as mammals. It would seem that 
there must be some cause tending to extinguish mammals 
on islands after a certain lapse of time, though they do well 
enough for a short period.” Tree-frogs and land-shells, 
though they possess but limited powers of locomotion, are 
very liable to be introduced by drift timber, and when once 
housed in localities such as, e.g., the Antilles, where they 
have few enemies, they may be expected to multiply not 
merely in individuals, but in species. To refute the notion 
of a cause tending to extirpate mammals in islands, we need 
only look at the Eastern Archipelago. Java and Sumatra do 
not differ greatly in area from Cuba and Haiti. In climate 
and productions there is great similarity. Yet Java has 
ninety species of indigenous mammals. Compare this with 
Cuba ! Yet the probability of extirpation by human agency 
must be much greater in Java. It has throughout good 
roads, a more ancient civilisation, a denser population, and 
a more energetic Government. Surely, then, if in addition 
to these varied agencies there were some general and un- 
known cause tending to extinguish mammals on islands, its 
fauna ought to be at least equally poor with that of Cuba. 
We fully agree with Mr. Pusey’s advice that we should 
find out by aCtual experiment what changes can be produced 
in a pure strain, and how, and that we should further seek 
to obtain a “ knowledge of the mode of action, if not of the 
nature of the forces by which the formation and precise 
arrangement of the several parts of the mechanism of an 
organism are determined, as well as of those laws under the 
influence of which one creature, say, is caused to be of one 
colour, while another — in other respeCts very closely allied — 
has a different colour imposed upon its corresponding tex- 
tures, and so with regard to other characters.” At the same 
time, whilst admitting the necessity of such researches, we 
must remind Mr. Pusey that work of this kind is being care- 
fully executed by not a few naturalists of merit. 
We are very far from considering that every point of the 
new Natural History has been fully demonstrated. We are 
only too conscious that with many enquirers zeal has out- 
run knowledge, and that conjectures have been accepted for 
established truth. But for this unsatisfactory state of things 
the best remedy is, we submit, to test the Evolution hypo- 
thesis in actual work. 
