484 THE HORSE'S POSITION IN THE ANIMAL AVORLD 



by 403,200 changes, a simple sum which gives in its quotient a period of 

 nearly 250 years as the interval available for an amount of change equal to 

 that wliich the foetus undergoes in a minute. If, instead of the human 

 ovum, the ovum of a rabbit had been taken for comparison, the contrast 

 in point of time would have been of necessity more striking, as similar 

 changes to those which occur in the human ovum during nine mouths take 

 place in that of the rabbit in a few weeks. 



It will be observed that the argument is not directed to the proof that 

 man was evolved from a jelly-fish or other primitive protozoon, but rather 

 to the fact of there having been according to the lowest estimate ample 

 time for the process, seeing that in the ordinary course of things a child 

 is evolved from a mass of protoplasm in a few months, and advances to the 

 condition of a man in the course of some twenty years. 



Enoucfh has been said to leave no room for reasonable doubt that what- 

 ever may be its limitation, evolution is a natural process, the successive 

 steps of which may be observed and recognized, as in the examples which 

 have been given. 



It is, of course, open to anyone to oppose the proposition that every 

 existing oi'ganism, animal and plant, was developed from some original and 

 undifferentiated protoplasmic matter, just as the foetus is developed from a 

 microscopic speck of protoplasm. Nor is it required for the present purpose 

 that the proposition should be accepted. It cannot be denied, on the other 

 hand, that under the influence of changes in the environment certain 

 important alterations of form and function do happen, and are indicated 

 by the presence among existing beings of organs and parts which are so 

 placed as to be devoid of any functional value, while a comparison of them 

 with similar and more developed parts in extinct races necessarily leads to 

 the presumption that they may be, and most probably are, rudimentary or 

 vestigial remains modified by the laws of heredity and the influence of 

 natural and artificial selection. 



Leaving now the general for the particular, the question which presents 

 itself relates to the facts which are offered by the anatomist and the palteon- 

 tologist, in regard to structure and conformation, bearing upon the state- 

 ment that the horse may be traced through a long line of extinct mammals 

 back to the earliest mammals of the Tertiary period. 



SPECIAL FEATURES IN STRUCTURE 



The horse is generally described as a remarkable animal, at once ex- 

 hibiting perfection of mechanism, complete balance of form, as well as 

 beauty of outline. Professor Sir W. Flower lays great stress on the 



