Many physicians who do their own laboratory work, and even many of the smaller clinical laboratories, do not have refrigerator facilities, and it is often a problem to keep certain substances at a low temperature. This problem was solved recently in the Little Rock City Laboratory, when the ice-man failed to fill the refrigerator, by utilizing a vacuum bottle. We wanted to keep some guinea-pig blood at a low temperature over night to collect the serum for the Wassermann reaction. The vacuum bottle was filled about one-half full with ice-water and the test-tube containing the blood was lowered into it and the cork inserted. In the morning the temperature was 10 C., and the serum had completely separated.
This simple expedient may be used as above, for keeping complement, corpuscle suspension, antigen and patients' serum for the Wassermann reaction; for keeping urine, small