576 Tuberculosis, 



.J 



■ Simultaneously with the elevation of temperature the pulse 

 and respiration often become accelerated, but not infrequently 

 they remain practically normal. Great depression and loss 

 of appetite are ecpially frequent and, in addition, usually from 

 the 6th to 8th hour, muscular tremors are observed (organic 

 reaction). The milk secretion is usually somewhat diminished 

 during the periqd of reaction and on the following few days, 

 o^ving to the fever and the diminished appetite. 



The decrease in the quantity of milk in reacting cows varies according to 

 Zschokke from 3.2 to 8%, according to Eber 3.4 to 6.1%, according to Bohni the 

 average is 9.2%, according to Eber & Fehsenmeier the maximum is 15%, according 

 to Martel 3.1%. According to the investigations of Tiraboschi the milk secretion 

 decreases during the first 24 hours after injection and again becomes normal on 

 the third day. Non-ineacting cows, however, also show a slight decrease (average 

 1 kg. as compared with 2 kg. [15%] in reactors). 



The intensity of the reaction and the extent of the lesions 

 bear no relation to each other unless this is an inverse one in 

 the sense that extensively tuberculous cows, hence emaciated 

 and weak animals, usually react with less intensity than robust 

 individuals in which the tuberculous' process is in its first stages, 

 or more or less localized. In greatly advanced cases reactions 

 may not take place at all. 



As a rule the tuberculin test does not perceptibly influence 

 the course of the disease or the health of the animal. In ad- 

 vanced tuberculosis the elevated temperature (fever) may per- 

 sist, though to a slight degree only, and this may, to a certain 

 extent, excite the tuberculous process to greater activity and 

 hasten a fatal termination. Virchow explained the unfavorable 

 action of tuberculin by the supposition that the thermal process 

 mobilized or stimulated the bacilli to greater activity, causing 

 them to multiply faster in the congested areas surrounding the 

 tuberculous foci. = In the lungs the increased bronchial secre- 

 tions were supposed to play an especially important part in 

 the dissemination of these organisms. 



As a matter of fact tuberculin exerts a peculiar action on tuberculous tissues 

 without destroying the bacilli which manifests itself, in some cases, in hyperemia 

 and increased juiciness of the tissues as seen in post-mortem examinations. This 

 local effect explains to a certain extent why tuberculin injections oc(;asionally 

 result in the development of acute inflammations in areas surrounding old tuberculous 

 foci, sometimes causing cicatrization and "healing" of the lesion. In other 

 eases, however, fresh tubercles will develop in this area and the tuberculous process 

 is fanned into renewea activity. 



Healthy animals are not aifected by as large or larger 

 doses as will produce violent reactions in tuberculous animals 5 

 there may occasionally be ait increase in temperature not ex- 

 ceeding 2° F. but general febrile s^nnptoms are still less com- 

 mon. According to Malm intravenous injections of 25.0 gm. 

 of tuberculin produce no toxic s\anptoms. The same indiffer- 

 ence to the action of tuberculin is observed in animals affected 

 with other disease than tuberculosis, reports to the contrary 

 are for the most part based upon incorrect interpretation of 



