128 Report or THE BactTEeRIoLoGiIst oF TH 
mined with a thoroughness that allows of safe generalization from 
the data obtained. 
In order that the reader may see the relation of this piece of 
work to the problem that is being studied, let the following facts 
be borne in mind. 
THE DANISH SITUATION. 
Dairying is one of the principal industries of Denmark and 
during the past two decades the government has fostered it both 
by the equipment of experts to study its problems and by pro- 
tective legislation. 
In 1890 Dr. Storch announced that, by changing the kind of 
bacteria that grow in ripening cream, he was able to change the 
flavor of the butter. 
Dr. Bang, after studying the conditions under which tubereu- 
losis was distributed among cattle, perfected a system of separating 
the diseased animals from the healthy ones and gradually replac- 
ing the former. In carrying out his plan, the feeding of calves 
upon the skim milk brought from the creamery was found to be 
a source of danger, but this could be removed by heating the milk 
momentarily to 85°C. (185°F.). 
As the result of these and other investigations, there has spread 
over Denmark a peculiar method of making butter —a method 
so successful that, to-day, Danish butter is a standard of excellence 
wherever it is known. 
Cleanliness in all details and an intelligent appreciation of the 
relation of bacteria to butter-making are widespread, but the key- 
note of their system is preparation of the starter itself and the 
cream to receive the starter. 
By a starter they rarely mean the mixture of bacteria, desirable 
and undesirable, which commonly receives that title in New York. 
They mean a mixture of known kinds, each of which has been 
found desirable in itself. This united action of several species 
gives a better flavor to the butter than could be obtained from 
any single species. 
