MILK INSPECTION. 
695 
idly so that as few of them may be allowed to germinate as pos¬ 
sible. It thus appears that pasteurization as at present operated 
does not succeed in conserving the natural assimilative proper¬ 
ties of raw milk, because the high temperature used imparts a 
cooked taste and coagulates the albumen. It also fails to pro¬ 
duce sterilization. The difficulty is to find a temperature low 
enough to avoid these chemical changes and yet high enough 
to produce sterilization. The microbes which present the most 
difficulty on account of their vitality are the bacilli and spores 
of tuberculosis and the spores of the microbes producing sour¬ 
ing in milk. Mr. Russel, of the Wisconsin Agricultural Experi¬ 
ment Station, strikes the key-note of the new treatment in his 
milk Bulletin No. 44. 
He writes : “ It is possible, however, by the titterniittent ap¬ 
plication of heat at successive intervals either at a compara¬ 
tively low temperature, say 140 Fahr., or higher, to kill out 
completely all living germs either in a latent or in a growing 
condition. This method can be used with milk, but it would 
enhance the cost of preparation so much that it is not applica¬ 
ble to its preservation under ordinary conditions.” 
The first of these successive heatings would kill all the 
vegetative germs, leaving only the spores. If the milk be 
allowed gradually to cool, these spores will find a temperature 
at which they will germinate and assume the vegetative stage. 
The spores would be then turned into bacilli, and a second 
heating will kill them. To make sure that no spores remain 
after this treatment, a third heating is made, which leaves the 
milk absolutely sterile. Of the two offending bacilli that of 
tuberculosis is by far the most important. Mr. Russel further 
states that it is killed by exposing it to 149 Fahr. for thirty min¬ 
utes, so it is easy to determine a thermo death point below that 
at which the chemical changes take place. This‘method of 
treating milk is the most perfect yet discovered,’but it is unfor¬ 
tunate that it is so costly. Still, the application of it is a mat¬ 
ter of such supreme ' importance to the public health that if 
the highest mechanical skill were employed the expense of 
