1 Jan., 1899.] QUEENSLAND AGRICULTURAL JOURNAL. 29 
Milk may acquire a taint some time after milking, and still it may be due 
to direct absorption. If it should happen to be placed in a room with odour- 
yielding substances, it can easily acquire it in a cold condition. Such belated 
absorption might be considered as due to germ origin, unless the conditions 
were carefully determined. 
ABSORPTION OF ODOURS FROM COWSHEDS. 
It is a current belief that milk does not take up odours so long as it is 
warmer than the surrounding air, and on this ground the practice of leaving 
_ the milk in the cowshed for a longer or shorter period of time is sometimes 
defended, more especially if the cans are arranged so as to preclude the possi- 
bility of the introduction of dust and dirt. ‘This belief is not infrequently 
formulated in this way :—Milk evolves odours when warmer, and absorbs them 
when colder, than the surrounding air. 
Recent experiments made by the writer seem to indicate that such a 
general conclusion cannot be experimentally verified. Exposure of hot and 
cold milk to an atmosphere charged with various vapours and odours, such as 
manure, urine, ensilage, and different volatile substances, showed that almost 
without exception both hot and cold milk absorbed distinctive odours in the 
course of a few hours to such an extent that they could readily be detected. 
Moreover, the intensity of the odour was almost invariably more pronounced 
in the warm than the cold sample, although precautions were taken to have 
the temperature of both samples alike at time of judging. 
This belief, that warm milk does not readily absorb odours, is contrary to 
the housewife’s experience who allows warm milk or warm food to cool before 
putting it into the refrigerator. Being warmer than the surrounding air, it 
absorbs more readily the odours arising from fruit, vegetables, or other food 
substances, than would be the caseif it was first cooled down. Suchacondition 
is not due to the retention of the ‘animal odours,’’ but direct absorption from 
without. : 
The practical bearing of this is that milk should not be kept in contact 
with air that is saturated with undesirable or marked odours. Even an 
exposure for a half-hour has sometimes been found sufficient to impregnate 
the milk with the odour of decomposing manure. The straining of the milk in 
the cowshed, and then its immediate removal, may not give time for the 
absorption of odours in a marked degree, but it should be borne in mind that 
the conditions at that time are the most favourable for the rapid absorption of 
any odours, and that in milk that is being produced in the best possible manner 
even such an exposure is not to be recommended. 
MILK AS RELATED TO PUBLIC HEALTH. 
The presence of bacteria interferes not only with the keeping quality of 
the milk, but affects the sanitary conditions of the same. Bacteria are also 
intimately connected with the production of disease that the mere mention of 
the word calls up to the minds of many dread visions of epidemics. That all 
bacteria should thus be considered as enemies of man is entirely erroneous, 
for, in many cases, they are decidedly beneficial, and particularly is this true 
with reference to those forms found in the milk. The mere fact that milk 
invariably contains hundreds of thousands, if not millions, of bacteria per ce. 
need not in itself cause alarm. Mere numbers of bacteria are no just criterion 
ag to the hygienic value of milk. Of course, just to the extent that bacterial 
life can be reduced in milk, just to that extent are the decomposition 
changes retarded, but milk or its by-products, skim milk or buttermilk, may 
contain scores of millions of germs and stili be perfectly wholesome from a 
hygienic point of view. 
The bacteria that exert a deleterious influence on human health are not 
necessarily those that are distinctively disease-producing—i.e., pathogenic 
bacteria; for, in many cases, sickness is caused by the ingestion of milk that 
is contaminated by putrefactive organisms.- 
