552 
between bull and pug-dogs. These changes, as seen in 
the pigs, are due to changed conditions and habits of life, 
to abundance of food, to the cessation of those activities 
on which the wild pig depends for its preservation— 
perhaps the phenomenon is enhanced by the principle of 
correlated growth and other influences. We have instances 
of similar modifications which take place in nature, as for 
example, the bull-dog codfish and the “ monstrous breed” 
of cattle known as niatas or natas. If we argue from the 
case of the improved pig, we may infer that an abundant 
source of food in the shape of luxuriant pasturage was 
the cause of this transformation in nature, as it is one of 
the conditions of such change in art. But if this is so, 
we can go a step further, for in the Sivatherium giganteum 
of the Pliocene Sivalik Hills of North-eastern India we 
have an animal with a similar configuration of facial bones. 
In one case, at any rate, we have evidence which goes 
to show that the change could not be brought about by 
Natural Selection. One of the strongest arguments in 
favour of Organic Evolution is based upon the evolution 
of the horse, as revealed in successive strata of the earth’s 
surface. The change from a five-fingered to a one-fingered 
manus is generally selected for special observation. I am 
not quite sure that it would be possible to show that the 
change, made gradually, would have been a matter of life 
and death to the differently endowed individuals ; but un 
less we can prove this, or give good reasons for supposing 
that this has been so, we have no right to attribute the 
change to Natural Selection. It may, however, be observed 
that concurrently with this modification of the manus, 
there has been a development of the teeth. On this latter 
point, Mr. Henry Fairfild Osborn says :— 
i! The teeth . . . furnish not only the most intricate correlations 
and readjustments, but the complete history of the addition of a