142 FINE WOOL SHEEP MUSBANDRY. 
spring. Some of its important principles have already 
been alluded to under preceding heads. The frst 
great rule of breeding is that like produces like. But 
this must be held to extend to blood as well as indi- 
vidual characteristics, or else it is a rule which will 
mislead the inexperienced. Let two mongrel animals 
of the closest resemblance be coupled together, and 
there is not the least certainty that they will repro- 
duce themselves in their offspring, or that their off- 
spring, of different years, will be like each other. I 
have already spoken of the cropping out of base blood. 
In selecting animals for coupling, especial pains 
should be taken not to interbreed those possessing the 
same defect, because in that case observation proves 
that the offspring inherit something like the aggregate 
of the defect of both parents—that is to say, if the ram 
is defective in the crops (in proper fulness back of the 
shoulders), to an extent expressed by 2, and the ewe 
to an extent expressed by 3, their offspring will pos- 
sess the defect to something like the extent of 5. Of 
course, this rule is not invariable, and would not con- 
tinue to apply to its full extent if breeding between 
the produce of these similarly defective animals was 
continued, for in that case they would soon have no 
crops at all. I like the arithmetical form of the state- 
ment, however, because it holds up before the mind 
in a tangible and impressive form the consequences 
of one of the worst errors of bad breeding.* 
* Tt would be strictly accurate to say thatif animals possessing the 
same defect are imterbred with each other, the offspring should be 
expected to inherit that defect to a greater extent than either parent, 
and that continuing such a course of breeding would goon increase 
the defect to the greatest practicable extent, and in the case of defects 
affecting the constitution of the animal, to a fatal extent. 
