BY C. J. POITND, F.R.M.S. ol 



It is a well established fact that if a tuberculous animal has been 

 injected with a large dose or with repeated frequent small doses of 

 tuberculin, it will fail to give a reaction temperature on a subse- 

 ^quent testing, unless a considerable period (many months) is 

 allowed to elapse for the previous dose of tuberculin to be 

 eliminated from the system. 



The following examples serve to illustrate how simple a 

 matter it is for animals to be fixeti up. and sold, in such a man- 

 ner that the purchaser is perfectly satisfied that they are abso- 

 lutely free from tubercolosis. 



Case I, — Mr. A has a well bred Ayrshire bull for sale. 



Mr. B , an intending purshaser, comes along and says 



to ^Ir. A , "I like the appearance of that bull, in fact I have 



taken a great fancy to him." 



Mr. A says, " Well, you can have him for a ten-pound 



note." 



" Alright," says Mr. B , " but now-a-days I get a l)it 



particular ; I will take the bull on condition that you test him 

 with tuberculin and he shows no reaction." 



This is agreed to by Mr. A , who invites Mr. B to 



come round in two or three days' time and witness the test being 

 /carried out. 



Now comes the opportunity for Mr. A- , for as soon as 



ihis premises are vacated by Mr. B he injects a large dose of 



tuberculin into the bull, which he has previously proved, to his 

 ■own satisfaction, has got tuberculosis in an incipient stage. The 

 next day, of course, the bull reacts to the tuberculin, but the fact 

 is only known to its present owner. 



On the following day Mr. B comes back with the stan- 

 dard dose of tuberculin, which iMr. A very courteously allows 



to be injected into his bull ; this is followed by a very careful 

 and accurate record of the animal's temperature from the twelfth 

 to the twenty-fourth hour after injection, with the result that 

 there is no perceptible alteration from the normal liefoi-e the in- 

 jection. 



Both seller and buyer shake hands and compliment one 

 another on the success of the test, and Mr. B- , after paying 



