INTRODUCTION. 



The "rule of thumb" butter making days are gone by. 

 No one at the present time can hold any important posi- 

 tion in the profession of butter making unless thoroughly 

 grounded in the principles that underlie it. It is true 

 many obscure problems yet remain to be solved, but by 

 the aid of the bacteriologist and chemist butter making 

 has now been fairly placed upon a scientific basis. 



Bacteriology has shed no less light upon the various 

 processes involved in the manufacture of butter than it 

 has upon the nature and causes of the diseases v^ith which 

 mankind is afflicted. The souring of milk, the ripening 

 of cream, the causes of the various taints common to milk 

 and cream are now quite thoroughly understood. Along 

 with this understanding have come many radical changes 

 in the handling of milk and cream and their manufacture 

 into butter as well as in the handling of butter itself. 



The best butter makers at the present time are the men 

 who are the most diligent students of bacteria and their 

 relation to butter making processes. Above their doors 

 is written in emblazoned letters ''Cleanliness is next to 

 Godliness." For cleanliness is the foundation of success 

 in butter making. 



