Issued August 31, 1916. 



U. S. DEPARTMENT OF AGRICULTURE^ 



BUREAU OF ANIMAL INDUSTRY. 

 A. D. MELVIN, Chief of Bureau. 



SPECIAL REPORT 



ON 



DISEASES OF CATTLE. 



delayed reactions have been noted which did 

 not appear until the 19th hour. In order to 

 be certain of every case observations must 

 be taken at least twice preferably about the 

 36th and 72nd hours. If only one observa- 

 tion can be made it sliould be on the 72nd 

 liour. Small iiiduration.s at the point of in- 

 oculation about tbe size of tlie head of a 

 parlor niati-Ii frequently occur in normal 

 non-reacting cattle, l>ut anytliing larger 

 than this ^vhich persists to the 72n<l hour 

 .should be considere*! a positive reaction." 



Cattle recently injected with tuberculin 

 frequently do not respond to tliis test. 



It is well to keep in mind the fact that 

 some tuberculous animals will react to the 

 subcutaneous test and not to the intrader- 

 mal, and some to the intradermal and not 

 to the subcutaneous test. By alternating 

 or combining these two tests and always 

 making a thorough physical examination the 

 maximum number of infected animals should 

 be detected. 



GH, HICKMAN, LAW, 

 , PEARSON, 

 ;OWER. 



N, 1916. 



•as* 



The Cutter Laboratory 



Berkeley, California Chicago, Illinois 



V. S. Veterinary License Xo. ."li 



\jyj V nt iv-LN -vi rj j. 



1916. 



.xx'^G OFFICE. 



