========================+============================================== | ANTISERA ANTIGENS +-----+-----+-----+-----+-----+-----+-----+---- | A | B | C | D | E | F | G | H ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Passer domesticus_ | 75 | 74 | 73 | 66 | 81 | 72 | ... | 81 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Estrilda amandava_ | 100 | 88 | 75 | ... | 79 | 72 | 53 | ... ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Poephila guttata_ | 95 | 100 | 77 | 67 | 87 | 81 | ... | ... ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Molothrus ater_ | 66 | 54 | 69 | 65 | 86 | 75 | 69 | 75 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Piranga rubra_ | ... | ... | 100 | ... | ... | ... | ... | 89 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Richmondena cardinalis_| 75 | 80 | 91 | 100 | 98 | 65 | 88 | 91 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Spiza americana_ | 65 | 68 | ... | 71 | 100 | 64 | 67 | 80 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Carpodacus purpureus_ | 70 | 71 | 71 | 61 | 89 | 93 | 53 | 70 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Spinus tristis_ | 72 | 74 | 73 | 60 | 89 | 100 | 60 | ... ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Junco hyemalis_ | 64 | 56 | 74 | 65 | 87 | 68 | 100 | ... ------------------------+-----+-----+-----+-----+-----+-----+-----+---- _Zonotrichia querula_ | 65 | 71 | ... | 67 | 89 | 75 | ... | 100 ------------------------+-----+-----+-----+-----+-----+-----+-----+---- Antigens were diluted with 0.9 per cent phosphate-buffered saline solution. Tests were run in standard Kolmer test-tube racks, each test consisting of 12 tubes. Each dilution was made on the basis of the known protein concentration of the antigen. The first tube contained an initial dilution of 1 part protein in 250 parts saline and each successive tube contained a protein dilution one-half the concentration of the preceding tube, ranging up to 1:512,000. Saline controls, antiserum controls, and antigen controls were maintained with each test to determine the turbidities inherent in these solutions. These control-turbidities were deducted from the total turbidity developed in each reaction-tube, the resultant turbidity then being considered as that which was caused by the interaction of antigens and antibodies. The turbidities were allowed to develop over a 24-hour period. In the early stages of this investigation the reactions were allowed to take place at 2°C. in order to inhibit bacterial growth.