VARIATION IN DOMESTIC ANIMALS 



455 



the highest possible degree. It is necessary, therefore, to exercise unusual 

 judgment in comparing the records of recent years, whether of race track 

 or dairy, with those which have been made a number of decades ago. 

 With reference to dairy cattle it is possible to make some very interest- 

 ing comparisons, first of old records as compared with those of the present 

 day, and second of records of cows of uncertain breeding at the present 

 time with those of cows of established dairy breeds. Thus Pearl has 

 unearthed the record of a scrub cow owned by Mr. George A. Scott of 

 Nashville, Tennessee, which in 1863 produced about 12,450 pounds of 

 milk. The record of an Old Sussex cow for the 5 years beginning in 1805 

 is given in Table LVIII. In recent years a grade Jersey cow produced 

 in 1 year 16,286 pounds of 



TABLE LVIII. PRODUCTION OF MILK AND BUTTER 



BY A COW OF THE OLD SUSSEX BREED, 1805- 



1810 (After Pearl) 



milk, the butter fat con- 

 tent of which, 844. 8 pounds, 

 was equivalent to 1056 

 pounds of 80 per cent, 

 butter. At the time this 

 record was made, it had 

 been exceeded by only 

 four cows within the Jersey 

 breed itself. Scrub cow 

 No. 131 in the government 

 herd at Washington, an 

 old cow between 15 and 

 20 years of age, was in 

 milk continuously from 

 October 6, 1909 to August 



1, 1913, during which time she produced 33,066 pounds of milk. It 

 appears, therefore, clearly to be established that so far as milk yield goes 

 much of the improvement of late decades may have depended upon 

 better methods of care and feeding; for over a century ago cows of very 

 great excellence in this respect were produced occasionally, and at the 

 present time cows of mongrel breeding may sometimes exhibit high 

 performing ability. Undoubtedly, however, there has been an enormous 

 multiplication of the best yielding families during recent years, even 

 if there may not have been any actual in'crease in dairy potentialities. 

 Obviously modifiability may act in a variety of ways. An interesting 

 specific instance in dairy cattle is reported by Kildee and McCandlish. 

 At the Iowa Station a comparison was made between seven cows of 

 mongrel breeding, and reared under unfavorable environmental condi- 

 tions, with seven calves, their offspring, of the same type of breeding 

 reared under favorable conditions since birth. The seven developed 

 scrubs, that is, those which had been reared under favorable conditions 



