THEORY OF GENERATION. 139 
regulate the temperament, bodily or mental power, colour or conformation, 
of the resulting offspring. 
12. AcquIRED QUALITIES are transmitted, whether they belong to the 
sire or dam, and also both bodily and mental. As bad qualities are quite 
as easily transmitted as good ones, if not more so, it is necessary to take 
care that in selecting a male to improve the stock he is free from bad 
points, as well as furnished with good ones. It is known by experience 
that the good or bad points of the progenitors of the sire or dam are 
almost as likely to appear again in the offspring as those of the immediate 
parents in whom they are dormant. Hence, in breeding, the rule is, that 
like produces like, or the likeness of some ancestor. 
13. THE PURER OR LESS MIXED the breed the more likely it is to be 
transmitted unaltered to the offspring. Hence, whichever parent is of the 
purest blood will be generally more represented in the offspring; but as 
the male is usually more carefully selected and of purer blood than the 
female, it generally follows that he exerts more influence than she does; 
the reverse being the case when she is of more unmixed blood than the 
sire. 
14. Breepine “Iy-anp-1n” is injurious to mankind, and has always 
been forbidden by the Divine law, as well as by most human lawgivers. 
On the other hand, it prevails extensively in a state of nature with all 
gregarious animals (such as the horse), among whom the strongest male 
retains his daughters and grand-daughters until deprived of his harem by 
younger and stronger rivals. Hence, in those of our domestic animals 
which are naturally gregarious, it is reasonable to conclude that breeding 
“in-and-in” is not prejudicial, because it is in conformity with their 
natural instincts, if not carried farther by art than nature teaches by 
her example. Now, in nature, we find about two consecutive crosses of 
the same blood is the usual extent to which it is carried, as the life of the 
animal is the limit; and it is a remarkable fact that, in practice, a conclu- 
sion has been arrived at which exactly coincides with these natural laws. 
“ Once in and once out” is the rule for breeding given by Mr. Smith in 
his work on the breeding for the turf; but twice in will be found to be 
more in accordance with the practice of our most successful (early) 
breeders. 
15. THE INFLUENCE OF THE FIRST IMPREGNATION seems to extend to the 
subsequent ones; this has been proved by several experiments, and is 
especially marked in the equine genus. In the series of examples 
preserved in the museum of the College of Surgeons, the markings of the 
male quagga, when united with the ordinary mare, are continued clearly 
for three generations beyond the one in which the quagga was the actual 
sire; and they are so clear as to leave the question settled without a 
doubt. 
16. WHEN SOME OF THE ELEMENTS of which an individual sire 1s com- 
posed are in accordance with others making up those of the dam, they 
coalesce in such a kindred way as to make what is called a “hit.” On 
the other hand, when they are too incongruous, an animal is the result 
wholly unfitted for the task he is intended to perform. 
THESE PRINCIPLES, together with the observations following upon them, 
have been quoted verbatim, at great length, by the late Mr. Herbert, in 
his elaborate quarto work on “The Horse of America,” with the very 
flattering testimony that he had done so “not for the purpose of avoiding 
trouble, or sparing time, but because he conceives the principles laid down 
to be correct throughout, the reasoning logical and cogent, the examples 
