126 



])isro,srs of Poiilfri/ 



ments witli tul)er('uliii prepared from the avian bacilli. 



These authors injected this tubercuUn witliin the layers of 



the skin (intracutaneous) in the comb and 



T wattles. The results indicate that this 

 method is reasonably satisfactory. Sum- 

 marizing the results of their tests on 601 

 birds, these authors found that 98 per cent 

 of the birds showing tuberculous lesions 

 reacted to the test. Only 8 per cent of the 

 non-reacting birds showed lesions. Numer- 

 ous previous investigators had obtained 

 negative results with the subcutaneous, 

 ophthalmic and cutaneous' method of ap- 

 plication. It appears that for birds the 

 intracutaneous method is the only one to 

 be considered of value. 



Technique of making the injection is very 

 important according to Van Es and Schalk. 

 Care must be taken that the injection is 

 neither too deep nor too superficial. A small 

 caliber syringe with a very fine needle (No. 

 26 or 27) is used. 



Owing to the denseness of the tissues, 

 especially the comb, it is often difficult to 

 inject even a small quantity, and consider- 

 able pressure is required to force the tu- 

 berculin into the tissues. The amount 

 injected into each bird was not carefully 

 measured but varied between 3V and 2V of a 

 cubic centimeter of a 50 per cent avian tuber- 

 culin. This tuberculin was prepared in the 

 usual way. 



Owing to its looser texture the wattle proved to be the 

 best place for the injection. The results of the tests were 



Fig. 17. — Syringe 

 used in the tu- 

 berculin test for 

 chickens. (Af- 

 ter Van Es and 

 Schalk.) 



