12 MASS. EXPERIMENT STATION BULLETIN 148. 



the contaminating factor so outgrow or obscure the colony of Bacterium 

 pullorum but that it was possible to recover it from some of the tubes. 

 At this point it is sufficient to say that the sjanptoms ■ — pre-mortem and 

 post-mortem findings of chicks dead of the disease — correspond with 

 those previously studied by the author.^ 



After twenty-five days the tests were considered completed, and Strains 

 Nos. 1, 2, 3, 5, 6 and 7 were all in perfect condition to continue the work 

 with the agglutinations. Pen No. 7, the control lot, never showed any 

 signs of disease, and until a few weeks ago (Dec. 1, 1913) 20 of the 22 

 were hving, healthy, vigorous birds. Only two deaths occurred among 

 the 22 control chicks; one was accidental and the other was killed on ac- 

 count of lameness. 



Making the Test Fluid. 

 Slant agar tubes were inoculated with Bact. pullorum, and grown in 

 incubator at 38° C. for one or two days. The growth was then washed 

 with carbolated salt solution (0.85 per cent, salt solution containing 0.5 per 

 cent, carbolic acid). The whole volume of washed material should have a 

 very definite cloudy appearance. This was put in the shaking machine 

 and shaken for one-half hour and then passed through sterile absorbent 

 cotton to strain out any clumps of bacteria which might remain. Care 

 should always be observed not to prepare the suspension too thin. A 

 good test fluid should be uniformly turbid. This should be retained on 

 ice or in lower part of refrigerator. 



Method of obtaining Blood Serum. 

 At first the method of cutting a spike of the comb was employed, but 

 since the bird's blood coagulates so quickly if in contact with tissue this 

 was found unsatisfactory. Then the method of cutting the wing vein 

 was employed, and by working carefully with this method it was found 

 to be suitable in every respect for drawing^blood^in 2 to 10 c.c. quantities, 

 causing but little effect upon the bird. At first great care was used in cut- 

 ting through the cutaneous tissue until the vena ulnaris was reached, and 

 the tissue teased away to make a clean cutting surface for making the 

 incision into the vein. By such treatment it was possible to get the blood 

 under quite ideal conditions, but the bird was submitted to considerable 

 discomfort. Finally it was found that the quicker the cut was made the 

 better the results, and less discomfort for the individual. The procedure 

 finally adopted for drawing about 6 c.c. of blood in a very short time, and 

 one which appeared to cause the individual no apparent discomfort, nor 

 disturb the egg laying later on, was carried out as follows: the bird was 

 laid on its side and the wing laid out near the edge of the table and turned 

 downward to afford a grade for the sample of blood to flow into test tube. 



' Gage, Geo. Edward: "Notes on ovarian infection with Bacterium pullorum (Rettger) in 

 the domestic fowl." Journal Medical Research, Vol. XXIV., No. 3; N. S. Vol. XIX., No. 3; 

 June, 1911, pp. 491-496. 



