118 ANNUAL REPORT OF THE Off. Doc. 



many cases, the lesions of tnberculosis consist in a local focus or 

 tubercle in some one of the internal organs, often in a lymphatic 

 gland, and there is no evidence or reason to believe that in such 

 cases the influence of the local infection extends beyond the tissues 

 actually involved. A considerable percentage of cattle, especially 

 those raised in dairy herds of eastern states is infected with tuber- 

 culosis in some degree, unless special measures have been taken to 

 free the herds from infection. Some animals containing local les- 

 ions of tuberculosis are in first class physical condition; they are fat, 

 sleek, all of their functions are normal and there is no evidence of 

 ill health unless tested with tuberculin when they will give the char- 

 acteristic reaction, and soon return to an aj^parently normal con- 

 ditions. 



The question may sometimes be asked: Why should such an ani- 

 mal be condemned and ordered to be killed when, upon post-mortem 

 examination, it was found by the meat inspector that the flesh may 

 safely be used as food? In reply, it should be said that strictly speak- 

 ing, such animals are not condemned by the State and ordered to be 

 killed. It is only required that they shall be cared for in such a 

 M^ay that they may not be able to spread infection. Every animal 

 that reacts to the tuberculin test in a characteristic way is believ- 

 ed to be afflicted with tuberculosis and every animal that is afflicted 

 with tuberculosis is a possi])le distributing center of infection. Of 

 course, all animals with tuberculosis do not, in all stages of the 

 disease and at all times, eliminate and distribute the germs of tuber- 

 culosis, but even if an animal is not spreading tuberculosis at a 

 given moment, if it is infected with tuberculosis there is the proba- 

 bility that it will, within a shorter or longer time, develop disease 

 to such a point that tubercle bacilli will be excreted. Consequently, 

 if the disease is to be eradicated from a herd it is absolutely nece«- 

 sarv that everv animal with tuberculosis, even those that have it 

 in the slightest extent, must be removed from contract with cattle 

 that are healthy, unless these healthy cattle have been immunized 

 from tuberculosis by vaccination. The condition may be compared 

 to a fire in the cargo in the hold of a ship. A fire may smoulder in 

 a bale of cotton for days and weeks, and make little progress. The 

 efficiency and safety of the ship are not impaired, but there is always 

 the danger that the fire may extend and cause much damage, pos- 

 sibly the destruction of the ship. So it is with tuberculosis in the 

 body of an animal. The smouldering ember may be minute; it may 

 not extend materially for a long time; it may, in some cases, become 

 extinguished from the operation of natural causes, but so long as it 

 is there it is a constant source of danger and the animal that car- 

 ries it should not be placed in contact with sound, unimmunized ani- 

 mals, nor should the milk of a cow so afflicted be used in the raw 

 state for food. On the other hand, if an animal is killed a postmor- 

 em examination will show the precise location, extent and character 

 of the lesion. Unfortunately, this information cannot be had during 

 the life of the animal. If it is found that the conditions are such as 

 to show that the lesion has not progressed beyond what is known 

 as local tuberculosis, the infected parts of the body may be destroyed 

 and the flesh may safely be used as food. If such an animal can 

 profitably be kept apart from healthy cattle and its milk can profit- 

 ably be used, after adequate pasteurization, there is no reason why 

 it should be destroyed and it is not required by the State that it 



