174 TUBERCULOSIS 
forms of pneumonia, and parasitic nodules. In each of these the 
diagnosis is made, either microscopically or by guinea pig inoculation. 
The use of tuberculin is of great value in the living animal. 
Tuberculosis in swine must be differentiated from parasitic lesions 
and certain forms of broncho-pneumonia. The histological study of 
the tissues and a bacteriological examination for tubercle bacteria will 
determine the nature of the lesion. 
Tuberculosis in fowls is to be differentiated from leukeemia lympha- 
denoma, sarcoma of the liver, asthenia, nodular teeniasis of the intes- 
tine, and excessive infestation with the air sac mite (Cytodites nudus). 
The diagnosis in these cases can be made largely from a histological 
study of the tissues. In asthenia the obvious lesion is emaciation. 
The same is true in case of the air sac mite.* The nodular teeniasis 
can be determined by serial sections of the smaller nodules in which 
will be found the heads of the flat worm causing the trouble. The 
nodular teniasis in fowls was described in Circular No. 3, Bureau of 
Animal Industry, 1895. It has been mistaken for tuberculosis a 
number of times. It is caused by a small flat worm described by 
Piana (1881) as Taenia bathrioplitis which is probably synonymous 
with Dovainea Tetragona Molin, 1858. In fowls, tuberculin does not 
give satisfactory results. 
Tuberculosis in sheep is to be differentiated from the nodular 
intestinal disease caused by Oesophagostoma columbianum Curtice. It 
is very rare in this species. 
Tuberculosis in horses is to be distinguished from glanders and 
parasitic lesions. 
The control of tuberculosis in cattle. Several methods have been 
proposed to eliminate tuberculosis from cattle. The preventing of 
the spread of the virus from the diseased to healthy animals is the 
most important precaution. The feeding of calves with infected milk 
and the introduction of tuberculous animals into a herd are two of the 
most important means of spreading the disease and therefore two that 
should be most carefully avoided. The system introduced by Prof. 
Bang of Copenhagen, Denmark, and generally known as the Bang 
method, has proven to be very successful in certain herds. It con- 
sists in the slaughter of the advanced cases and the isolation of the 
*In 1903 the writer examined a number of fowls with Dr. Powers, Health Officer of 
Los Angeles, that were thought to be tuberculous because of the extreme emaciation. 
The examination showed an excessive invasion of air sac mites with no lesions in the 
visceral organs. 
