10 



MASS. EXPERIMENT STATION BULLETIN 323 



.04, .02, .01, .005, and .001 cc. The tests were made at a temperature of 78° to 

 80° F., and readings were recorded after a 3-minute incubation period. Table 3 

 shows the results of testing 10 samples with the whole blood test. The results 

 with the tube test represent the serum titre of the birds four days prior to the 

 time the samples were collected for the whole blood test. Six of the ten samples 

 were tested twice. On second test the reaction did not appear as strong as the 

 first. It may be seen that the degree of reaction with the whole blood test corre- 

 lates in a measure with the degree of reaction and titre observed with the tube 

 method. While a reaction was obtained in all samples tested, it was extremely 

 weak in two cases and might have been overlooked under field conditions. It 

 is of interest to note that an amount of blood as small as .001 cc. is able to produce 

 a reaction. 



Table 3. --Influence of blood-antigen dilution 

 on decree of agglutination. 



Whole Blood Test Serum Agelutination Titre 



(Tube Method) 



Bird Trial Amounts of Citrated Blood (cc.) ■ 



No. .04 .02 .01 .00.5 .001 10 20 40 SO 160 320 640 12S0 2560 



Legend 

 Tube Method: 4 — complete agglutination 

 3 — incomplete agglutinati* in 

 2 — partial agglutination 

 1 — slieht agglutination 

 — no agglutination 



\\ !■■ Blood: 4 — numerous and large clumps developing rapidly 



3 — numerous and medium clumps developing quite rapidly 

 2 — fine clumps and less numerous developing rapidly or slowly 

 1 — very fine clumps and few in number 

 — no agglutination 



Iii a second trial, five positive birds were tested with both the whole blood and 

 the tube methods, as shown in Table 4. Each sample was tested twice with the 

 whole blood test with practically the same results. The citrated as well as the 

 uncit rated blood serum was tested with the tube method, with no significant 

 differences in titre. Three birds in this group (91040, 91963, and 90993) were 



