INFLUENCE OF DISEASE UPON MILK 91 
physical examination in addition to a tuberculin test is 
necessary because the tuberculin test alone will not detect 
all cases of tuberculosis. Ostertag, for instance, tested 
with tuberculin nine cows affected with udder tubercu- 
losis and two failed to react. The adoption of such a 
plan, however, immediately upon the introduction of 
dairy inspection in districts in which tuberculosis is com- 
mon will meet with many practical difficulties. Few 
dairymen in such districts are able to bear the expense 
of disposing of non-clinical reactors as well as clinical 
cases and of replacing them with healthy cows, even 
with state assistance; and the state would not have suffici- 
ent funds to render the assistance provided by present 
laws if such a plan was generally adopted. Difficulty 
would also be experienced in replacing the reacting cattle 
with animals free from tuberculosis, and this would in- 
crease with the number of herds included in the inspection. 
The opposition of the dairymen concerned would be 
very generally incurred and there would not exist that 
friendly codperation between the inspector and dairy- 
man which is necessary to insure the most satisfactory 
results. .A careful and thorough physical examination 
repeated at intervals is next in the order of effectiveness. 
By this method those cows can be discovered which are 
the most concerned in the contamination of milk with 
tubercle bacilli. Such an examination should include a 
careful inspection and palpation of the udder and supra- 
mammary lymph glands; inspection of the milk in each 
quarter; palpation of the other superficial lymph glands; 
examination of the general condition of the animal; in- 
spection for nasal discharge; examination for cough; 
examination of the respiration; auscultation of the lungs; 
examination of the digestive tract, especially for chronic 
