Abstract
Sera obtained from routine Wassermann test were tested for agglutinins, for B. melitensis and B. abortus in the average outdoor dispensary population in Chicago. Brucella melitensis variety Melitensis (A) No. 428, and variety abortus No. 456 were sent to us by Alice C. Evans and were used as our antigen. The technic recommended by Evans 1 was rigidly carried out. Up to the present, 200 sera have been tested; dilutions have been 1:10, 1:20, 1:40, 1:80, and 1:160. Fourteen sera have been positive within this range of dilutions. All positives were retested and found in each case to check with the previous tests.
Table I gives our results.
Evans 2 has reviewed the literature. She found 58 sera in 500 from patients suffering with a variety of diseases to be positive in dilutions of 1:5 to 1:40, and suggests that these were produced as a specific response to Br. melitensis ingested in cow's milk, although such an infection may not necessarily have caused a notable illness. Three of our positives in 1:40 dilution were normal pregnant women. The others were in a variety of non-febrile cases. A milk-drinking history can always be ascertained from a patient. If the explanation of the occurrence of these agglutinins in the serum offered by Evans is correct, we have found so far 7.0 per cent of the average dispensary population have a specific response to B. melitensis and B. abortus.
This is a preliminary report.
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