Feb. 2, 1871] 
NATURE : 
271 
{ . 
Along with this theory, these two writers introduced | the last few i i i 
another, of the modus ead by which this evolution | Ae in GO oe ee oaeaction 
is mainly or entirely effected, that of a process of Natural 
Selection from spontaneous variations. This doctrine was 
supported by an enormous array of facts, and by a 
brilliancy of argument which caused it at first to be as 
During 
eagerly and generally adopted as the other. 
has been setting in in an opposite direction, and attention 
has been widely called to difficulties in the way of the full 
adoption of the theory of Natural Selection, at first over- 
looked, the force of some of which has been admitted, 
with his usual candour, by Mr. Darwin himself. Some of 
these objections were pointed out by Mr. J. J. Murphy in 




























Fic. 2.—Upper Figure—Antechinus minatissimus (iplacentad). 
Lower Figure—Mus delicatulus (A/acenta/). 

Fic. 3.—Cuttle-fish. Ventral and Dorsal Aspect, 
his elaborate essays, entitled “ Habit and Intelligence,” 
published in 1869; on others Mr. Mivart dwells in the 
volume now before us, the most recent contribution to 
this department of literature. 
A theory may be true, and yet may not be ade- 
quate. To take an illustration from the realm of mind. 
The believer in the doctrine of innate ideas will 
admit that the greater number of our conceptions 

|are the result of habit, imitation, and training; he 
| believes, however, that there are others which canuot thus 
| be adequately accounted for, and which are innate and 
independent of subsequent education. In the same 
manner Mr. Mivart and those who think with him freely 
admit the potency of Natural Selection to have produced 
the greater number of the specific forms and organic 
structures we see around us ; for the production of others 
