20 MODERN DAIRY PRACTICE. 



mentioned concerning this point, as well as all details in 

 bacteriological technic. 



Before concluding this short explanation of bacteriologi- 

 cal methods of investigation I will state that a large num- 

 ber of bacteriological studies at least in their beginning 

 do not necessarily require for their execution a complete 

 laboratory, equipped with expensive and delicate apparatus. 

 A number of simple pieces of apparatus fit for sterilizing 

 material for bacterial cultures at a high temperature, etc., 

 may be found in almost any modern kitchen. This is of 

 great importance, since the field of investigation cannot 

 always be near laboratories. A large portion of the bac- 

 teriological studies upon which this book is founded could 

 not, in the nature of things, be made in a city laboratory, 

 but were only made possible because a small so-called 

 bacteriological hand-laboratory was amply sufficient for 

 their pursuit. Thanks to this fact I have been able to 

 conduct my investigations in the midst of the industries 

 whose conditions I intended to study from a bacteriologi- 

 cal point of view. 



As an illustration of the importance of bacteria in the 

 dairy industry, I will report an event which strikingly 

 shows how the dairy products on a farm may for a long 

 time be entirely spoiled on account of infection from a 

 single harmful species of bacteria. On the estate Duelund 

 in Denmark, belonging to Hofjagerrwster Friis, who is 

 so well known in the Danish dairy world, the principles 

 of rational dairying have been followed since the introduc- 

 tion of the dairy movement into Denmark. High-grade 

 outter to which premiums were often awarded has lon 

 been made on the estate. But about a year ago it suddenly 



