No. 4.] CATTLE COMMISSIONERS' REPORT. 229 



the examination. All lung sounds are made either during inspira- 

 tion or expiration of the breath ; never during either cf the 

 intervals. 



Diagnosis. 



To give such special directions as are possible, that will point 

 out clearly and distinctly the presence of tuberculosis, will be 

 but to repeat what has already been said while speaking of the 

 symptoms. 



It is a well-known fact that there are many instances in which 

 active, healthy-looking, fat cattle, after having been butchered for 

 their beef, are found to show limited, but nevertheless strongly- 

 marked effects of the disorder in their lungs, livers, bowels, etc. 

 These animals, so far as can be ascertained,, have never shown any 

 symptoms of disease whatever and certainly it would be difficult to 

 find finer or healthier looking cattle than many of them are at the 

 time they are slaughtered. If an animal shows no symptoms what- 

 ever of being diseased it certainly will he impossible to lay doiun any 

 rules that tvill detect disease in him. 



On the other hand there are many cows that cough frequently, 

 have a rough, unthrifty looking coat of hair, are thin in flesh, and 

 have perhaps, in addition, some one or more of the other symptoms 

 of tuberculosis, which, upon examination of the chest, show no 

 symptoms of disease of the lung, and which upon being killed and 

 carefully examined present no evidence whatever of tuberculosis. 

 In these instances, unless we place sole reliance upon the symptoms 

 furnished by a physical examination of the chest, we shall kill 

 many animals as tuberculous which a post-mortem examination ivill 

 shoio to be free from the disorder. 



As has already been pointed out, there are a line of cases, and 

 they are very far from being infrequent, in which, with the other 

 general symptoms, rales are present in the bronchial tubes. Such 

 an animal being examined at one time may show these plentifully ; 

 the same animal examined again will show no evidence whatever 

 of a rale either at the spot where the sound was formerly heard or 

 at any other part of either lung. We must always remember that 

 moist rales or rattles are due to the presence of more or less fluid 

 in the bronchial tubes ; and that while this fluid may be due to 

 the effects of tuberculosis, it may also be due to bronchitis, local 

 or general, from some other cause ; or that even there may be a 

 rattle of a transitory sort that is not due to any appreciable dis- 

 eased condition. Therefore, if we allow ourselves to destroy an 

 animal upon this sym))tom, without first having taken care to see 

 that the rale is peimstently shown in the same place, we shall often 

 destroy one that the post-mortem examination will show to have 



