THEORY OF GENERATION. 137 
being eight inches higher than the withers of a horse of sixteen hands. 
Something more than this has however been done, and I myself once saw 
a horse clear a stone wall two or three inches above six feet high, with 
the slightest possible touch of one stone with a hind foot, but sufficient to 
dislodge it. Very few horses, however, can be relied on to cover more 
than twenty-five feet in width, and four feet, or four feet six inches in 
height, and an average hunter will not often do so much, especially if at 
all tired by a long run, or if without the excitement attendant on the 
chase. 
CHAPTER X. 
THE PRINCIPLES OF BREEDING APPLICABLE TO THE HORSE. 
THEORY OF GENERATION—IN-AND-IN BREEDING—CROSSING, ADVANTAGES AND DISAD- 
VANTAGES ATTENDING ON EACH PLAN—CAUSES OF A “‘HIT’’—IMPORTANCE OF HEALTH 
OR SOUNDNESS IN BOTH SIRE AND DAM—BEST AGE TO BREED FROM—TIME OF YEAR 
BEST SUITED TO EACH VARIETY OF THE HORSE—INFLUENCE OF SIRE AND DAM 
RESPECTIVELY—CHOICE OF SIRE AND DAM—SELECTION OF BLOOD IN EACH CLASS— 
THE KIND OF HORSE MOST LIKELY TO BE PROFITABLE TO THE BREEDER—CON- 
CLUDING REMARKS ON BREEDING. 
THEORY OF GENERATION. 
THE IMPORTANCE of understanding the principles upon which the 
breeding of the horse should be conducted is so great that every one who 
superintends a stud, however small, should study them carefully. To do 
this with advantage, he must investigate the changes which take place 
after the union between the sexes, and must endeavour to ascertain the 
influence which the sire and dam respectively exert upon their offspring. 
In the year 1855, while engaged in preparing the article on the breeding 
of the horse in “ British Rural Sports,” I carefully drew up the following 
epitome of the laws which govern the generation of the mammalia. Since 
then, the subject has constantly been before me; but, in spite of the 
numerous investigations carried on by other observers, I have seen no 
reason to modify, in any material degree, what I then wrote; and I shall, 
therefore, to prevent confusion, insert it entire, what slight additions may 
be necessary being included within parentheses. 
1. THe unton of the sexes is, in all the higher animals, necessary for 
reproduction; the male and femaie each taking their respective share. 
2. THE OFFICE OF THE Mate is to secrete the semen in the testes, and 
emit it into the wterus of the female, (in or near which organ) it comes in 
contact with the ovwm of the female—which remains sterile without it. 
3. THe Fremace forms the ovwm in the ovary, and at regular times, vary- 
ing in different animals, this descends into the uterus, for the purpose of 
fructification, on receiving the stimulus and addition of the sperm-cell of 
the semen. 
4, Tar Semen consists of two portions—the spermatozoa, which have 
an automatic power of moving from place to place, by which quality it is 
believed that the semen is carried to the ovum; and the sperm-cells, which 
are intended to co-operate with the germ-cell of the ovum in forming the 
embryo. 
