LIMITS AND STANDARDS. 



165 



to raise the cry that the standard adopted by the Society is 

 too high ; on the contrary; I think it is very judiciously fixed, 

 but, in upholding the standard of purity, it should not be for- 

 gotten that the cows have never been asked for, nor have given 

 their assent to it, and that they will at times produce Inilk below 

 standard. A bad season for hay-making is, in my experience, 

 almost invariably followed by a particularly low depression in 

 the quality of the milk towards the end of the winter. Should 

 the winter be of unusual severity and length, the depression 

 will be still more marked. Long spells of cold and wet, as well 

 as of heat and drought, during the time when cows are kept 

 on pasture, also unfavourably influence the quality and, I may 

 add, quantity of milk." 



Table XXXIV. will show the probable number of samples 

 per 100,000 examined which may be expected to be found between 

 the percentages named. 



TABLE XXXIV.— Percentage of Fat and Solids not Fat 

 IN Mixed Milk. 



Table XXXV., p. 166, shows the percentage of samples which 

 have fallen below the Government Standard for fat in morning 

 milk during May and .June since 1900 ; it is practically only in 

 these months that any serious number of low samples occurs. 



In au extended series of analyses of milk, the author has found 

 that the number of samples yielding any given percentage of fat 

 is in agreement with that calculated by the usual methods from 

 the theory of probabilities, provided that morning and evening 

 milks are treated as separate series. This shows that standards 

 can be calculated by actuarial methods from the actual 

 results. 



iiy a formula based on the theory of probabilities, the author 

 has calculated standards for each month below which milk 

 should not reasonably be expected to fall for both fat and sohds 

 not fat, and in the case of fat has confirmed them by taking the 



