246 MASS. EXPERIMENT STATION BULLETIN 257 



difficult to brush the vaccine into them. Frequently it was necessary to vac- 

 cinate slightly higher up on the leg tlian usual, where the follicles were some- 

 what more mature and open to< a greater extent. 



In connection' with the tentative standardization of the cutaneous vac- 

 cine (3), it wasi noted that when less than 200 m,gm. of virus were used in 

 the vaccine, it failed to produce local reactions ("takes") in all trials. When 

 mtore than this anioimt of virus was used a more pronounced generalized 

 reaction was the result, Tliese conclusions were based on the results obtained 

 after working with birds from five to six months of age or older. In this 

 and the following experiment the 100 mgin. vaccine produced clear-cut "takes" 

 in every instance. The birds) used in these experinients were yoimger and 

 ha,d not developed the degree of natural cutaneous resistance to the vaccine 

 that older birds had developeu. 



Group 3. 



Eighteen Rhode Island Red pullets of the same hatch and strain were 

 used, and six were left unvaccinated as controls. They were 68 days old on 

 the day of vaccination. Here a,gain three vaccines were used, containing 300, 

 200 (standard), and 100 nigm. of virus, respectively. The immaturity of the 

 follicles in these birds) necessitated more careful vaccination than in the pre- 

 vious expermient. 



Interpretation. — The normal temperature of the domestic fowl varies 

 considerably. The records in Table 1 show a slightly higher normal range of 

 temperature in the White Leghorn cockerels than in the Rhode Island Red 

 pullets and cockerels. This perhaps can be attributed to the greater activity 

 of the former breed. They were older than the Rhode Island Reds, but this 

 should not have influenced the temperature in this case. 



A careful anaJys'is of the temperatures taken during the stage of infec- 

 tion in all the experiments shows a slight increase over those taken during the 

 preliminiary stage. The increase averages less than 1° F. and is but slightly 

 more noticeable in the vaccinated than in the unvaccinated control groups. 

 The average temperature of both groups in all experiments during the stage 

 of recovery is lower than that recorded during the stage of infection. 



It is difficult to draw any definite conclusion from these data on rectal 

 temperatures. The slight increase in temperature during the stage of infec- 

 tion was of little importance. 



Table 2 shows the minimiun, maxmium, and average gain in weight at- 

 tained by each group, as a whi>le, during the stage of infection in the three 

 experiments. It presents the weight records of Table 1 in a fonn suitable 

 for more ready interpretation. The figures for each group were obtained by 

 determining the diflFerence between the minimum and maximum weight for 

 each bird during the stage of infection in the three experiments. The smallest 

 of the^ differences is the group minimiun and the largest the group maximum. 

 The sum of these differences for each bird, divided by the number of birds 

 represents the average gain of the group. 



