1866] 71 
sclocfcion." Ir saying, that if we support this theory, we must suppose that a certain 
Bpecios was developed in both regions, ho will, I know, pardon me if I state that 
the " developmental " idea is misunderstood. It is not necessary for a moment to 
imagine that a dual development has taken place. On the contrary, may we not 
surmise, that long before that remote period when the bed of the Atlantic had no 
existence as such, and when the diy land was continuous between what we now 
term Europe and America, this species had already spread itself over a vast area ; 
and that, when the outlying boundaries of the region peculiar to it had become 
separated by an immense expanse of ocean, it still continued to preserve its pecu- 
liarities intact ? I think so. Natural selection does not work in a regular manner, 
but is most capricious and uncertain in its eflfects, as is well exemplified in the 
human race ; for do we not find that the Hebrew nation, dispersed as it is from one 
end of the globe to the other, has preserved from remote historic times, and still 
preserves, under all conditions of surrounding circumstances, its physical charac- 
teristics ? whereas the inhabitants of the States of America have already, in very 
few generations, acquired national physical peculiarities of the most marked nature. 
The occurrence, therefore, of an identical form in two widely separated districts, 
does not prove that it was " developed " in both, but rather that it is slow to 
become affected by various changes in surrounding conditions, in contradistinction 
to those forms which, there is every reason to believe, readily adapt themselves to 
organic physical changes, and are highly susceptible of alterations in conditions. 
I must protest against the assertion that " it is the business of entomologists to 
deal with facts and not with hypotheses." When the matter is purely descriptive 
entomology, the more facts are adhered to, and hypotheses dispensed with, the better ; 
but when on a subject of phaenomena similar to that which we are now consider- 
ing, it is our duty to enquire how these facts became facts, and if we are precluded 
from perfectly satisfying ourselves as to these points, we should lean towards that 
hypothesis which, to our individual inward conviction, seems the most reasonable. 
Above all, we should never become conservatives in science, allowing traditional and 
educational influences to weigh against a comparatively recent idea, because it is 
recent. The days in which naturalists occupied themselves exclusively in mechanical 
descriptive work, or in " facts " only, are fast passing away, and the time has com- 
menced in which facts are no longer considered as valuable for their intrinsic 
merits alone, but as guides to point out the intricate path of philosophical enquiry. 
The physician does not seek to cure a disease through a simple knowledge of the 
symptoms ; he first seeks rather to ascertain the probable cause, as evidenced by 
the symptoms or facts. I know of no more expressive, more trite, language bearing 
on this point, than the following extract from a lecture delivered by the Rev. Charles 
Kingsley at the Royal Institution. He says, " I can conceive few human states 
" more enviable than that of the man to whom, watching for his life under the tropic 
" forest, Isis shall for a moment lift the sacred veil, and show him, once and for 
" ever, the thing he dreamed not of — some law, or even mere hint of a law, explain- 
*' ing one fact ; but explaining it with a thousand more, connecting them all with 
" each other, and with the mighty whole, till order and meaning shoot through 
" some old chaos of scattered observations." — Robert McLachlan, Forest Hill, 
2nd July, 1866. 
