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 oesophagus, 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- 



