1876.] Biological Controversy and its Laws. 211 
continually discovered which are altogether new to Science. 
But such discoveries are most plentiful — 
a. In countries imperfectly explored, becoming rarer and 
rarer as any region has been more fully explored by 
naturalists. 
b. In the lower forms of animal life, and especially in very 
minute species. 
In England the discovery of a new beetle an inch in 
length, or of a butterfly the size of Vanessa Io, and not ob- 
viously imported from some other part of the world, causes 
no little sensation. On the Continent the occurrence of a 
nondescript bird or reptile would certainly not be passed 
over as an every-day affair. Even in India, a buffalo, a deer, 
or a cat, unknown alike to native and British sportsmen, 
would excite astonishment. But if such sudden modifications 
ever have taken place, is it not likely that they would—oc- 
casionally at least — still occur, and that they would not be 
exclusively confined to imperfectly known countries, to mi- 
croscopic species, and to the lower groups of the animal 
kingdom ? Perhaps Mr. Mivart may say that the “ internal 
forces or tendencies ” of species and the external circum- 
stances under which they are placed, have already readied 
upon each other, and that no further changes are now 
possible. We reply that external circumstances continue to 
alter, and that, consequently, if a perfect equilibrium was 
at one time attained, the conditions under which it exists 
being no longer the same, it is liable to be disturbed, thus 
necessitating on his hypothesis fresh changes. The produc- 
tion of some authenticated case of a new animal or vege- 
table form evolved out of an old or known one, unessential 
for Mr. Darwin, is for Mr. Mivart an absolute necessity. 
The illustration in which the new hypothesis is conveyed 
makes, after all, very little room for inward tendencies. 
The sand, or other powder in which the sound-figures are 
embodied, lends itself with the same facility to one kind of 
vibrations as another. The plate, its supports, and the 
violin-bow are all outward circumstances adting upon the 
sand. Thus the entire illustration is one which might have 
been very appropriately used by Lamarck, and in so far forth 
as it is fully and fairly herein expressed “ Mivartism ” is 
merely Lamarckism under a new terminology. Lamarck 
makes, indeed, no explicit reference to the internal nature of 
animals; but he must have implicitly assumed it, otherwise 
there would have been nothing upon which outward circum- 
stances or forces might readl. One distindlion is, however, 
that Lamarck, like Darwin, supposed the variation of species 
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