FIRST CENTURY OF DAIRYING IN NEW SOUTH WALES. 



diseased, are transmitted to their offspring. " Like produces likei" 

 But while experience teaches the constancy of hereditary tiansnus- 

 sion, it teaches just as plainly that the constancy is not absolute and 

 perfect, and this introduces us to another law, namely, that o>i varia- 

 tion. All beings possess a certain flexibility of organisation. In a 

 state of nature variations are comparatively slow and infrequent, but 

 under domestication they occur much, more often. Climatic condi 

 tions and food also affect the matter. 



If all breeders had exercised a tithe of the shrewdness possessed 

 by the patriarch Jacob we would have a much better state of things 

 to-day, and there would be less need to trouble over the next law, 

 that of atavism of ancestral influence. We say " trouble" advisedly, 

 because, as a rule, not the best qualities of our dairy cattle are re- 

 produced in this way. This is borne out by the proverbial remark? 

 that however good a cow may be, there is no telling beforehand what 

 sort of a cal-i she will have. Obviously, therefore, certain peculiarities 

 may be dormant for a generation or two, and then reappear in the 

 progeny. This pertinacity with which hereditary traits cling to the 

 animal for generations, in a latent, masked, or undeveloped condition 

 is remarkable. 



The next law deals with heredity, with the relative influence of the 

 parents on the offspring. Some writers maintain that only the male 

 parent is capable of improving the breed ; others that the offspring 

 bears the greatest resemblance to that parent, ruo.le or female, which 

 has exerted the greater generative influence, and that the only certain 

 agents are the best powers of both sexes. Others assert that eaeh 

 parent contributes to the formation of certain structures and the 

 development of certain qualities. Further, they hold that the male 

 parent chiefly determines the external characters, the 'framework, bone 

 and aiuscle, organs of sense and skin and locomotive powers ; while 

 the female is responsible for internal structure, the vital organs and 

 functions of secretion and nutrition. On this point Dr. Carpenter 

 says : " Although no universal rule can be laid down, yet independent 

 observations seem to establish that such a tendency has real existence." 

 Much confusion is often shown in arriving at any definite understand- 

 ing on this law owing to instances, sufficiently common among the 

 lower animals where the offspring exhibit more or less distinctly over 

 and beyond the characters of the male by which they were begotten, 

 the peculiarities also of the male by which their mother at some for- 

 mer period had been begotten. 



The next law is that of in-and-in breeding, a system by which the 

 best or worst characteristics of a breed may be intensified according 

 to the wisdom or otherwise of those who are intrusted with such a 

 two-edged implement. It has long been a disputed point whether the 

 system of breeding in-and-in or the opposite one of frequent crossing 

 has the greater tendency to maintain or improve the character of 

 stock. The term in-and-in is often very loosely used, and is variously 

 understood ; some confine the phrase to the coupling of those of 

 exactly the same blood, namely, brothers and sisters ; while others 

 include in it breeding from parents and offspring ; and others simply 

 employ the term to embrace those of more distant relationship. l' ( >r 

 the latter the term breeding in, or close breeding, is deemed more tit 

 ting and advantageous, it is certainly Nature's plan of fixing type, 

 for among gregarious ruminating animals in a state of nature it. is 

 largely practised with no apparent ill effect- in-m generation to gene- 

 tion, probably for centuries. 



The practice of crossing, like that of close breeding, has its Mnnig 

 and its weak side. Substantial arguments can be brought both tor 

 and against it. Judiciously practised, it offers a means of procuring 

 animals superior to and more profitable than those of any pure breed. 

 Crossing is generally understood to refer to the alliance between ani- 



202. 



