92 PRINCIPLES AND PRACTICE OF MILK HYGIENE 
tympanites and diarrhoea, and inspection for vaginal 
discharge. In some cases it will also be necessary to take 
the temperature and pulse and to examine the lungs and 
pleura by percussion as well as auscultation, and in suspi- 
cious cases, when a definite decision cannot be made, it 
may be necessary to apply the tuberculin test to the ani- 
mal under examination or to collect sputum from the 
trachea or cesophagus, secretions from the vagina, scrap- 
ings from the rectum, and milk, and submit them to a 
microscopic examination and inoculation test (see p. 
275). In tuberculin-testing such animals, a large dose 
of tuberculin must be used, from two and one-half to five 
times the ordinary dose. When the microscopic examina- 
tion of material from an animal of this kind gives a nega- 
tive result it cannot be accepted as final, but guinea pigs 
must be inoculated. If death does not occur earlier, the 
guinea pigs must be held for two months after inoculation 
before they can be killed for post-mortem examination. 
Most owners would prefer to dispose of an ordinary cow 
on suspicion rather than feed it for this length of time 
and keep it isolated and not be permitted to use the milk 
without heating it. It is usually more satisfactory to 
apply the tuberculin test in such cases. Clinical cases 
of tuberculosis are usually unthrifty and are generally 
not good milkers and the owner can usually be convinced 
that such animals are unprofitable. Another reason for 
disposing of such cows, which will appeal to the owner, 
is that they are sources of infection for the other cattle 
in the herd. As a rule, the removal of animals of this 
kind, advice and assistance in securing healthy cows to 
replace them, and proper attention to the other features 
of dairy inspection will gain the confidence of the owner 
rather than his opposition, and after a system of inspec- 
